2 staging, LGB 7 - for those who are looking for more info.

MilanD

After some time and discussion here on the wall, here's the set-up in its final and finished state. Link to original discussion is at the bottom for who ever wants to read through the 99 posts.

On 2 stages, the boiler pressures for low-fire can be dialed in and adjusted further, and I'll do it as needed. For each person's circumstances, this can be adjusted to fit your own set-up. Right now, I have the high limit set-up at 10 oz, which triggers low-stage. It stays low to about 2oz at which pressure the valve goes back to full fire. As the temps dip this winter, I'm going to see if I can get good heat everywhere at under 10 oz. All this depends on how well the system is vented and balanced and the heat loss.

My experience today, on a 55 degree day, is that the boiler fires and makes steam quite quickly. After it reaches the 10 oz, it will stay in low for about a minute, then drop out and back to high for a minute or so, and so on about 3 times (links to videos are below). At 4th drop to low, it will stay there for a few minutes longer, even with the feed pump bringing water from the condensate return tank. Then the tstat ends the call and that's that. So burners always fire, between high and low.

My set-up has a water feeder on a return condensate tank. As such, this pumping of water quickly reduces the boiler pressure. However, as the system gets to full pressure, and after a few modulations (High-Low-High-Low), it will stay and hover around 0.2-0.3 psi until the final water feed drops it out of low fire. This is on a 55 degree day.

A few notes on the system.

Our LGB 7 is set up on a 1-pipe system with approx. 2000 edr (it was measured when installed and I have doublechecked to almost all the rads, so we are about right). Set-up follows the practice of 1.33 pick-up. We also do have a zone that closes for one large auditorium that's not used a whole lot. When this happens, we are essentially, oversized. It is my supposition that lowering the input BTU through low-staging will prevent boiler from cycling on high pressure even more than what it was doing so far - I have 3 big mouths on one of the 3 loops, one at the end of the main, and 1 each at the end of a very long sub-branch and a long rad riser.

This 1-pipe system I was running this winter on about 12 oz of pressure after all the venting was installed and corrected. Last yar we ran it at about 1.5-2 psi. We have vented the 3 main loops. 2 of the mains are 3'' out of the boiler room and each is vented with a Hoffman 75 each, and the 2.5'' on a 3rd loop is vented with BJ Big Mouth, with some idiosyncratic rad risers branching off 2.5 loop with each having its own Big Mouth. Each of the 3 main loops is approx 180ft from boiler room to the vent. We don't have wet returns, but FT and Warren Webster 78 traps, with a 50 gal condensate return tank.

Here's the link to 3 videos and the tree of the 2 stage set-up.
https://www.amazon.com/photos/share/FAVB0VOgPYfQHRZj3UTDdurzaymuLDEcEIlBugT31xI

Discussion that came before this post, with how we arrived to this point and with other boiler room pics, for those who are interested, is here:
http://forum.heatinghelp.com/discussion/160248/how-to-delay-boiler-from-firing-again-right-away-after-max-op-pressure-is-reached

I will update this post as the winter rolls on.

A big thank you to @Hatterasguy and to @Gordo for pointing me in the right direction, and to all who chimed in on the other posts.

MilanD

Thanks Hatt! I'm all gitty!

MilanD

Ha! Yes, that too. No, I was def grateful for the fast and good work. These guys are 1st class. When it comes to both fixing and installing, these guys are the best. No bs is right and no job too small nor blowing smoke. Bob is always phone call away (I have his cell #!!) and always answers. And I listen, most of the time.

I knew they do big jobs, but only today that it is industrial boilers with catwalks around them, steel tube, breweries, prisons... You name it, and then they squeeze me in. Some guys working there have been there for decades. Sign of a good business treating the techs and the customers right.

On the am after I confirmed the boiler leak, 5 people came by: the owner (Tom), controlls/sales/chemist guy (Bob, who's like an uncle to me), 2 boiler installers and, when the section had to come out, their 2nd installer. I worked along them too, but mostly stayed out of the way, except for egging out that one 2" nipple. The guys were nice, said it was rotted out.

They can pipe in to spec, anything. They can set up controlls, make sure what their end is runs as it should. What they don't do is ins and ours of systems like ours, you know, like providing answers to questions people come here to find out, or suggest simple improvements to systems like mine. Big ones, sure. These, nope. Lost art...

But again, people mostly don't know how good steam can be, and that old dead guys who came up with thease systems were smarter then than 95% of people today. Even guys who do residential only, as painfully evident with a massive number of people, like myself, searching for answers they can't find from their "techs". Technology evolves, sure, but we all are here bc we are standing on their shoulders. There had to be Pupin, so there could be Bell's long distance telephony. There head to be long distance telephony for there to be dial up, and adsl, etc...

And we have to know to ask.

Thanks again Hatt! You and Gordo have a beer, lunch, beer and lunch, or whatever you want (some Camp Washington Chilly comes to mind), if you ever come down to Cincy.

Cheers!

MilanD

1/26/17
Update on the op of the system.
Overnight set back was at 66 F, outdoor temp 35-36F over night.

Outdoor temp 38 in the am. 66F inside tstat setting. One zone (large auditorium) closed off, total reduction of EDR due to zone close, 504 EDR.

8:30 - ~9:30 am 66F to 69F rise out of overnight setback.

Next first cycle after the setback rise:

10:51 1st call on 69 tstat hold cycle. Header too hot to hold in less than 2 min. (water sat in boiler for 1h20min after last cycle)

10:54 psi needle rise, vents venting
10:57 water pump press drop from 0.4 to 0 psi, quickly back up to 0.4psi
10:58 op steady at 0.45 psi
10:59 water pump press drop to 0.2 psi, back to 0.45 in 30 sec
11:00 op pres 0.5psi
11:01 water pump, op press drop to 0.3psi, up to 0.5 in 20 sec
11:01 pres up to 0.55psi
11:03 water pump, op press to 0.35 and up to 0.55 in 20 sec
11:03 op press climbing 0.65 at 11:04 low fire stage engages
11:04 water pump on low stage, op press down to 0.25psi and slowly falling, slowly slowly
11:05 op pres 0.2, water pump, exits low stage .15pi, press down to 0
11:06 pres climbs on high fire
11:07 0.65 psi, enters low fire, op press slowly falls
11:08 water pump, press down to 0, high fire
11:10 0.65 psi, low fire, water pump, op press to 0.15, back to high fire (45 sec total)
11:11 low fire, water pump
11:13 high fire 0.15 psi
11:13 tstat satisfied 30 sec into high burn
11:14 water pump and done.

Total run time ~23 min.

All rads warm/hot. All spaces comfortable temp.

Gas meter reading start 2322.32 CCFU
Gas meter reading end 2324.78 CCFU

Total fuel 2.46 ccfus = 246 cfus

At $.65 per ccfu nat gass, this heating cycle cost us ~$1.60 in fuel.

Gordo

@MilanD : You are most welcome, Sir! I appreciate the kind words and the sentiments behind them.

LionA29

Thank you for sharing @MilanD.

MilanD

@LionA29 - my pleasure.

@Hatterasguy shared another link on the other thread, and got me thinking how to slow down the system for even more eaven heating and fuel economies by taking advantage of 2 stages now available, without tekmar or ecosteam...reading that article I realized I came to a similar conclusion independently. My question is though, what controller is used to anticipate and fire the boiler on simmer for a long time? Can't be done on tstat alone, or maybe it can!

Link to this post is here:
http://forum.heatinghelp.com/discussion/comment/1462009#Comment_1462009

Now the next step.

We have the Honeywell TH8320WF tstat. I have observed it, for the first time today, cycle the boiler while the display temp stood at 69F (and then again 71F). Time it took between 2 firings at 69F indoor (and 35-37 outdoor) was 90 min with nice 2 staging when one of my zones (discussed prior) closed the total 1975 edr boiler and dropped the attached edr to about 1475. Heating call ran a nice 23 min cycle, as shared above.

After I had the pm bump from 69 to 71F (outdoor temp 37F), now with the zone open and all but 2 rads calling (have a leak somewhere so this riser is off line), we got from 69 to 71 at the tstat in about 63 min. Although I didn't sit by the boiler to observe the whole cycle (not that nerdy, but almost), I did see: a) low stage engage on the full load, and b) tstat cut the burners out 2 min before tstat showed 71. For a moment there I thought the boiler quit working...

After we got to 71, boiler was off for 110 min before firing again to maintain 71F in the building. Outside temp was still at 35-37 range, 1-2 mph westerly wind... Old bldng, all original windows but for the 6 bigger ones on 2nd floor south and west I had replaced (2 outside walls in each space, could not keep warm, and now I added some radiation in there too), brick building, no insulation.

And here's what I'm thinking: and following discussion from this post and getting some clues from @ChrisJ below and other discussions:

http://forum.heatinghelp.com/discussion/160971/2-psi#latest

Without using the tekmar or ecosteam, lower the op pressure to 5 oz, and 2nd stage low burn between 1 and 5 oz, so the system will take time to satisfy the tstat... I will do this tomorrow and the only unknown is how will the tstat react to taking this long to maintain heat... I'll guess we'll see tomorrow.

ChrisJ

The Ecosteam messes with my VisionPro all of the time.

What happens normally is the Ecosteam shuts the boiler down, but the VisionPro keeps calling for heat. In 5 or 10 minutes, the VisionPro is finally satisfied and stops calling for heat.

With it set to any given CPH, you'll find this causes it to call for heat a little earlier, and run it longer, or try anyway.

That's why I always view the Ecosteam as something to keep my VisionPro in line.

MilanD

@ChrisJ and @Hatterasguy

I have a feeling that a proper steam tstat should be able to accurately measure indoor heat loss alone (faster on colder days, slower on warmer), should be able to, alone, measure how long it took to be satisfied against the indoor heat loss and run boiler when needed based on past experience at the given heat loss (within the set temp, small variations in tem swing). Then, we could possibly decide how to set high/low ranges, either crudely with vstat or finely with a Dwyer switch.

Do modern tstats do that? Ecobee perhaps? Chris said his Vision Pro is overzealous and ecosteam keeps it in its place.

This is why @Hatterasguy , I'm thinking that lowering of op pressure and narrowing down of 1st stage (low fire is 1st stage, right?) may give a more even, and slower, heating against the building heat loss.

My particular issue is that I have a basement used for classes and about 1/2 of mains have to be uninsulated to heat the basement, and having tstat that will anticipate the heat loss. Visionpro does have the outdoor sensor if I'm not mistaken, but I'm not sure if it's used to calculate heat loss and temp maintenance.

On a positive side, most of the building gets to heat at the same rate, balancing is almost there. On the negative, heat loss is not even... Rooms with a bigger outside walls and more windows just cool quicker from rooms with smaller outside walls. So for me, cycles that are closer together and greater radiation in rooms with greater heat loss will be the key. 90 min between cycles is a bit too long, but aside from bumping tstat up 1 degree on a tstat program schedule to get the boiler to come on. there is nothing much I can do. This is why I think that if the tstat (as this electronic one we have) also looks at how long it takes to satisfy, perhaps it will also calibrate when it fires up again.

Today, boiler ran before tstat showed 69 drop to 68, and it also stopped at 70, before showing 71 for which it was set on the 69-71 bump. But I think it also has to be measuring how long it took to satisfy, and calculated accordingly. Or maybe I'm just projecting through hoping it did.

MilanD

1/27/17

1st 69F stat call on 69F hold after 66 set-back - update on new set-up.

So, I've commented on another thread and here, after reading some articles sent my way by @Hatterasguy (again, Hatt's the best!), and with notes on @ChrisJ system, I've been thinking about this whole slowing down steam thing... so I tried something a bit different today.

Prelim conclusion: steam speed (aka pressure) may be your enemy even more than you thought before...

Scenario 1/27/2017:

Outside temp today is 31F (as opposed to 38F yesterday)

Slight digression: to put one day's gas use into perspective as we go forward, our total 24 h gas use to heat the building (from after the am burn yesterday to after this am burn out of the set-back) was 39.98 ccfs, per meter that is also temp to volume adjusted (whatever that means - actually, it means they charge you more volume when it's colder), on a 38-31F outside temp drop.

So, same as yesterday's am setting, at 8:30 am the tstat called for 69F indoor after overnight set-back to 66F. It got warm and tstat was satisfied at about ~9:40... give or take, I wasn't here and saw tstat was satisfied around 9:40 - about 10 min longer than yesterday... I then snapped a photo of the gas meter when I got to the building and compared it to yesterday at the same time. After the set-back heat call this am, total use for 24 h is 39.98 cffs. No other gas equipment on the meter.

Here's what I've done this am - although - I didn't catch the start of the tstat call until I felt my office rad was getting air action on the vent and warm (3rd from the boiler and I also use it to test various vents for speed and function as I sit here for about half of the day). I ran to the boiler room (*disclaimer, may have in fact only walked briskly), to see the pressure was already at 0.55 psi. As my low stage was set to 0.65, I went ahead and dialed down the 1st stage on the vstat to trigger the low burn at 0.55 psi (about 8 oz on the vstat), and then dialed down the high-burn differential as far as I could as the pressure dropped, almost to 0 on the psi scale (of note: '0' is marked more on a '1' mark, so when it says '0', it's really a 0.1psi.

What I observed is the following: burners kicked back to 40% of full burn in low-burn (gas pressure on the gas valve goes from 3.5wc to 1.2 wc). For a few cycles, the pressure was dropping slowly, then quickly as the water feed motor engaged, kicking back into high burn. After about 3 or 4 cycles (I didn't write down the count as I was fiddling with the differential on the low-stage vstat), 0.55psi triggered another low burn, and the psi stayed right there at 0.55, quite steadily. There were 2 water feeder calls, pressure dropped after each, but - this time, after getting to about 0.20 psi (I'm calling '0' notch a '1'), pressure climbed slightly and stayed at 0.25 steady until tstat turned off the burners.

Total burn time, 21 min, give or take, compared to 23 yesterday. Today temp was 31F, yesterday was 38F. I can't attest to the wind, but the big American flag that I can see from my window in the park across the road, is flapping about the same as yesterday. I'm going to call that, close enough.

I then ran around the building checking the rads for heat, and rooms for overall comfort, and all rads were warm, some more some less (TRVs on 5 rads on the idiosyncratic 2.5" main I wrote about earlier). 2nd story auditorium was zoned off. Returns from the main house loop (I'll call the 2.5" loop 'main house') were hot in the boiler room, as was the Ballroom loop. I checked the last rad in the Ballroom, it was warm, as was the last rad on the main house loop.

In conclusion, it took about 2 minutes less to heat the same spaces on 7 degree colder day, with low burn being triggered at 0.55psi (as opposed to 0.65), and with lowered high burn cut-in pressure to '0' per gauge (as opposed to 0.15 psi yesterday).

So, by today's measure, it looks like slow is better, low is better...

I am only surprised that I observed the psi go UP on low stage after the load seemed to be at capacity. My supposition was that the pressure would eventually drop back to 0 as the load would ask for more heat than the boiler supply would give out on low burn, thus reducing the pressure and not hold on low burn. I was wrong... it held steady.

The only thing it didn't do is add more water on that low 0.25 burn. If I can dial it in with the control I have, to keep low burn after that 0.25psi water feed and then allow it to build back up to 0.25psi, I think we'll be golden.

Next step will be to check this set-up with all zones opened. Yesterday I had the 2nd story Auditorium call for heat too, and the highest psi build on the full load (minus the 2 rads that are off line) I observed was 0.55 psi. So, perhaps, this 0.55 psi will be the sweet spot for the low burn trigger.

I'll fiddle some more with it being at 0.5 (8 oz), to take the most advantage of the 2-stage set-up, and the lowest optimal high-burn cut in.

Cool.

EDIT: This am burn was a total of 2.69 ccfs (2.46 yesterday). I have a feeling it's bc of the temp volume adjusting, but what I am not understanding is how it burned more, on 2 min less run time, and on clearly longer low-stage burns. We'll see - I may have to sit by the boiler some more.

2nd 69F call just happened, my rad is warm at 12:45. 2nd burn on 69F tstat call yesterday happened at 13:58. So we are a full hour early on this burn, per temp drop and what ever the tstat is now doing... Burn ended at 12:58.

12:45-12:58 pm. Dialed down high-burn low psi trigger by another 1/4 turn down on a differential and 3/4 turn on the upper oz pressure limit on the 2-stage vstat controller. This time, I again got the burners to stay on low fire after 3 water fills, AND again BUILD pressure on low burn to about 0.25psi on the gauge where it kept steady until the tstat was satisfied. All rads warm, and not all the way across, and all rooms comfortable temps. We might be getting somewhere...

I think, the key is to get the tstat room to warm slowest, or in balance with the coldest room. I mentioned in another thread of wanting to install a TRV on it, but that's a bad idea as it will turn off the rad at set temp. I installed instead a old Hoffman 1A I had sitting here, and dialed it down, way down. BTW, if you have them Hoffman #1As, take off the cap screw and see where the vent hole is compared to the cap - the dial stamped on the cap was way off on my vent... my stamped '1' was covering the went about 1/2 way and not all the way.

ratio

The pros may have an opinion, but perhaps you could throttle the pump to the point where you don't knock down the steam, & therefor stay at low fire? In theory, as long as you pumped somewhat faster than you boiled you shouldn't get into too much trouble unless your returns are really slow.

ChrisJ

If you wanted to, using the setup I have you can easily control pressure down to around 1/4 or even an 1/8 of an ounce, accurately.

You'll need to plumb in an air gap rather than a pigtail for the switches, and you'll need a 0.015" snubber from Mcmaster.

http://www.dwyer-inst.com/Product/Pressure/DifferentialPressure/Switches/Series1800

You have to be careful, as the last number is what pressure it maxes out at, in inches of water.

I currently have a 1823-2 plumbed in, which is set to trip at 2" of water and it tells the Ecosteam to keep the boiler off for 10 minutes.

A 1823-20 is likely more what you want as it does 3" to 22" +-.

You can create a Vaporstat using these in a way, but I don't remember how.

Does anyone have Mark's schematic for the Dwyerstat? @Hatterasguy ?


Check Ebay for these switches as you'll often find them brand new for around $20-30.

MilanD

@ChrisJ @Hatterasguy

Thanks guys! I will definitely look in this direction next.

First, I didn't get to post after another afternoon fiddle with the system. Long day... As I'm still working only off a tstat and now 2 stage on vstat (not yet 2 days old), I wanted to see how the system would react to lower overall op pressure now that there is low fire stage. What I observed yesterday was super-encouraging.

One of the articles Hatt shared with me yesterday (it was on the thread we highjacked on 2psi op pressure) talked about low, low being the way to go. Of this, Chris is one living proof, plus his system would be considered undersized by known standards, and it still functions as it should. Further, the article touched on venting rates of modern rad vents nowadays having to be higher, sometimes by a factor of 10 vs old systems' vents, pointing to Garry Gill's charts etc... So, due to using modern fuels and all on/all off burning and the lack of simmer, and the psi being in 1-2 range on most systems using h-well off-the-shelf trols, people need to compensate by venting... (I now ask myself, how did ptrols get to be the go-to tool for pressure control, when they are, clearly, still too high for the residential application?!) Another comment somewhere today, as well as one of Dan's books I read, talk about steam actually slowing down higher the pressure is...

Dan has this article (I read it 3 times - slow learner):

https://heatinghelp.com/systems-help-center/what-ive-learned-about-steam-pressure/

END OF PART 1

MilanD

PART 2

Soooo, today I thought to my self: 'slow the steam down now that you can fire the boiler down'... let's see how far.

Starting with: I already know that on high fire only, I need 12 oz and a few cycles to get the last rad hot (meaning to get steam to the rad) when one of my zones is off. Despite all the venting, 1975 sq. ft. steam from the boiler is too much for piping/venting/rads when 500 EDR of rads are off-line. With pick-up factor, this makes the boiler 2x the attached load. I vented the best I can, and at 12 oz I've got pretty good results.

I also know that when all rads are calling (including the zone that's usually off), despite the high limit being 12 oz, my system runs at about 0.55 psi (per gauge) on the full demand, and stays there until all rads are hot and the tstat is still calling. That's about 8-9 oz... So, I've had to compensate with the pressure when one zone was off.

Secondly, we all know the majority of systems get hot quickly and then overshoot. Some instances, you do need them to get hot quickly, like my auditorium or churches (same scenario in both cases), but for the most part, slow and steady should be dialed in. Only to input BTUs that are lost to building heat-loss is ideal. BUT, majority of systems don't have the ability to modulate, low-fire, or use anything but tstat and h-well trol (both of which are not suited for today's steam - especially the trol!), and many are not vented or balanced well, so this is close to impossible on common systems with one stage burn, trol and tstat set-up.

Due to the Auditorium scenario, I like the get-hot quickly thing, not bad if it can be used to get heat going, and then percolate. 2 stage burners do just that - give you a turbo, then lay off.

Hereby we get back to Chris and other common knowledge about rads not needing to heat all the way through but on the coldest day. Coal systems used to do it. @Jamie Hall wrote in one of the threads here about the coal fire being modulated with the use of pressure via supply air buffers. I've seen this in old books but didn't get what it did until he explained it. As the pressure rises, air supply is cut back throgh chains and pullies, coal fire is choked, until the boiler pressure drops and opens up the air supply, and on like that, all day long.

However, I've not seen this rads half way warm happen on our old system, so I first installed the TRVs. They worked fairly well - kept things comfy in the rooms close to the boiler, but also, threw the system into a spin by even further undersizing it each time trvs would close. I had installed 5 on 5 rads on the main house 2.5" main. The ones closer to the boiler work great. The one later in line, not so much, and the farthest radiators from the boiler, without the trv heated poorly. I also have a weird branching at the end of the main house main which I mentioned before, so with trvs closed, pressure would rise even quicker on the oversized boiler, and last rads wouldn't get warm enough to heat the space... vaporstat at 12 oz made sure of it. I would need to increase the run time, and by raising the pressure. This I didn't want to do as it wastes fuel. But, I noticed that the only time these last rads would heat would be after the pull out of an overnight set-back as there would be some cycling on steam (and this is one clue to keep in mind - long system run). Not much, but some and long enough that some steam would make it back there.

So, to alleviate this venting issue, I added the big mouths to 2 end rads. This helped get the steam to the main and to those rads, but now made it first steal steam from TRVd rads earlier in line so they wouldn't heat until steam got to the end of the big mouths first, and then they would heat, but the rads at the end would still not heat quickly enough... they would, and it was better, but not up to my ocd standard. Etc, etc,... on 12 oz of pressure.

I was running out of tools, so I worked on slowing down earlier rads with TRVs even more... it was on to balancing balancing balancing... And I got there. But, I didn't like the 12 oz. Full system when open runs at 8 oz (0.55 psi per my gauge).

Then I started asking question about delaying the boiler - to let latent heat work before boiler would fire up again. Then, Hatt and Gordo pointed me to 2-staging.

We installed that 2nd stage vstat controller, and it seems like the whole new world opened up.

END OF PART 2

MilanD

PART 3

So, now, back to last test done today. You guys say how vstat is just not accurate enough... well, I got it to do just this by the end of the day.

Tstat calls for heat (weather on hold or on temp bump from 69 to 70 - I did both scenarios). I lowered the low-stage cut in to 0.5 psi on gauge (slightly under 8 oz on the vstat) and furthered dialed the differential, testing it after each pressure rise on low stage by another 1/2 screw turn. It finally did what I was suggesting to do in earlier post...

Heat calls, high burn. After a few minutes main is hot, steam is making, and pressure is working its way up. It takes some time to get it to build up to 0.5 psi. At this point, low-stage kicks in, psi drops, water feeder feeds, and lo and behold, burners keep on low. Huh? Yep. Pressure starts to slowly climb on low burn, to about 0.25 psi per gauge and hangs there... for a while... then water pump engages, and same scenario repeats again, and again, each time pressure drops and then goes up to 0.25. Then, the tstat stops calling and it's done. All in low fire. 31-35 F outside temp.

After this, I touch my returns, too hot to hold. I run around the building and check the rads and rooms for comfort. Nice and toasty, rads some more some less warm, mostly not all the way across, except for a few in cold spaces, as they should. (I'll post notes on fuel use separately).

Remember that last rad from the above story - way more hot than before. That room was never warm in the past. I added the rad there and tripled the EDR for the room (it was undersized, there's a post about that on the wall). In fact, now, this rad and all rads heated more than before. My downstairs big auditorium - all rads hot... All on 0.25 psi, which is btw, 6.93 in/H2O.

I'm thinking I am now getting the best of 2 worlds: rapid steam build and distribution with the high burn, and low dissipation and even heating with low-stage burn.

One thing I am not sure is if I may be losing efficiency as I may be heating the system too slowly. It is definitely better balanced than before. I've been taking gas meter readings after each heat cycle, so I'll go back to high-low-high-low as the first day, and measure it (wish I remembered to do it the first day -- was too gitty )

As to tstat location, actually, just slow down the rad in the room with the tstat so it follows the rest of the space, and no need to move it, imho. Hoffman A1 is great for this. I am now thinking about using them instead of the TRVs. They won't be closing and with low fire now available, it may actually be better. Watch me sell them off on ebay next fall!

In conclusion, I think I've done what I can to push the steam into that farthest room and do it well. It is now actually getting warm quicker than before, but most importantly and counter-intuitively, with low fire. More of the rads get hot than was a case with high burn only, and not all the way across. So building gets warmer more evenly on low fire low pressure (low stage) burn cycle. And remember the mention of last rads heating only on long cycle after the set-back? Yep, that is also no longer the case on low burn.

I really don't know what to say. Chris is on it - no pickup and undersize burners.

Last thing left is to see how this performs with all the zones open and how it performs with temps in the 20s or teens...

I have a small suspicion this may not work and I'll have to turn up the low-burn cut-in, but maybe not. Perhaps the load being bigger it will allow the vstat to sense greater drop in pressure after the low burn, to engage the high burn in this scenario, as the steam demand will be greater and hopefully it will register the pressure drop at the boiler that's sufficient enough for this to work.

I have a feeling that with this, and perhaps with the addition of EcoSteam or some such control may give us exact efficiencies I was after, while raising comfort too.

(I'll contact Mark back after all this testing has been done, we already exchanged a few emails and he's given me the Dwyer schematics - too bad it's like reading Norwegian. I may have to take-up some electrical and electronics training in more depth.)

One last thought, completely impractical: the most efficient system is the one that's off. Move to a warmer climate.

Bio

Well I think you practically made a one pipe vapor system, with a one pipe system, achieving efficiency and comfort at the same time may be a challenge in that big of a system, but not impossible, nice work

MilanD

Thanks @Bio!

MilanD

ChrisJ said:

If you wanted to, using the setup I have you can easily control pressure down to around 1/4 or even an 1/8 of an ounce, accurately.

You'll need to plumb in an air gap rather than a pigtail for the switches, and you'll need a 0.015" snubber from Mcmaster.

http://www.dwyer-inst.com/Product/Pressure/DifferentialPressure/Switches/Series1800

You have to be careful, as the last number is what pressure it maxes out at, in inches of water.

I currently have a 1823-2 plumbed in, which is set to trip at 2" of water and it tells the Ecosteam to keep the boiler off for 10 minutes.

A 1823-20 is likely more what you want as it does 3" to 22" +-.

You can create a Vaporstat using these in a way, but I don't remember how.

Does anyone have Mark's schematic for the Dwyerstat? @Hatterasguy ?


Check Ebay for these switches as you'll often find them brand new for around $20-30.

Thanks again @ChrisJ I am now re-reading the thread for all the input. Your suggestion to 3-22" snubber was right on. With the size of our system this is exactly the setting I think I got to with the vstat on the zoned off load. My 3psi gauge is showing 0.25 on the simmer, and the boiler stays there until satisfied. This is a tad under 7" in/H2o (same as w.c?)

Next question is how the system will act with all the rads calling for heat, but after some more thinking about it last night and this am, I think I'm pretty much there.

I was also thinking about the efficiencies with this set-up. I think the only next step left will be to further time burns against tekmar or ecosteam-like controls, and perhaps dial in on burners and stack vent with a barometric damper. This is, however, more in the realm of science fiction for my current abilities and it may have to wait. I also don't want to create a "monster" that noone in town will know how to work on should I ever move on to a next thing with my job.

With the burn going from 780MBTU to about half that, for the boiler to use more fuel, it would have to run twice as long. In my current observed operations, that's not the case. It's actually about the same run-time, give or take a few minutes for wind conditions.

A question on a side: when the 2-stage gas valve dials down gas pressure from 3.5 wc to 1.2 wc, is the given btu input then also proportionally reduced, as in this example own to 34.28% of the full burn btu imput?

MilanD

There are 2 valves. The 2 stage valve label shows 2 factory preset pressure settings: 3.5 and 1.2. The other one shows nothing, and is model no one number off the 2 stage valve. Pic of both valves is in my amazon album shared in the first post on this thread (sorry, can't figure out how to get it again on my phone). The paperwork online also shows these can be changed from factory preset.

Given there are 2 valves (master and secondary), it's possible combined output is 2.4 on lower stage. By the same logic though, combined high stage is 7. Makes for the same ratio, unless one stays put at 3.5 or some other preset. This may well be the case.

To my ear and eye, the sound and look of fire really dials down to simmer. I'll post video of this on Monday. It's remarkable how low it's firing and how it slowly simmers the water. That's why I asked if the valve preasure reduction ratio relates proportionally also to the btu reduction. Sure sounds and looks like it to me.

Lgb 7 sticker shows min btu at 540 mbtu and max 780mbtu. That's some 33% downfire per sticker. Given one valve is fixed pressure, the other at 1.2 low fire would indicate proportional relationship and downfire to 67%.

MilanD

Yes. I believe the sticker too. And one valve being fixes also makes sense.

I just did some back of napkin calculations. On 67% of full btu, it gives 1,300 edr output. If we call hot pipes hot after high burn and remove 1.33 pickup factor, low stage edr goes up to 1,742. I have a feeling when all zones call, low burn will do them too, or it will be awfully close. If not, high stage will kick it up on pressure drop.

I'll call duke on monday to see the btu rating of our gas.

BobC

Have you checked the combustion numbers at low fire? Make sure the flue temperature has not dropped too low at low fire.

Bob

MilanD

@BobC

The fire down is 67% of 780 mbtu. It's factory enabled setup. We didn't do the stack temp, but at 522 mbtu I'm pretty sure we're ok.

BobC

Check that flue temperature just to be safe, is this chimney in the center of the house or is it on an outside wall?

Bob

MilanD

Outside wall. What should the min temp be?

BobC

If it were much less than 350 degrees I would be concerned. If that chimney is exposed on 3 sides and does not have an insulated liner the flue gasses could condense before escaping. Without a liner that could destroy the chimney over time.

Bob

MilanD

Sorry, wrong chimney desceiption - chimmey is on the ouyside, but exposes only on 1 side on the outside wall. 3 sides are inside the building. I'll bring by my remote thermometer and stick it in up the flue to make sure.

MilanD

Here's another 2-week update on what the 2 stage burner is doing and how it's looking.

My conclusion:

2-stage can turn any setup into a one pipe vapor system, under the right venting, from what I'm seeing - finally. Oversized or rightly sized, all the same, based on what I'm seeing with our particular set-up that's right sized for full edr load, but oversized most of the time, with one zone off (2000 edr vs 1500 edr). I have a zone that's closed on all but 6 hours a week, which in essence makes my boiler oversized most of the time.

So, high burn is used to get to the nominal op pressure, which will be, by the way, lower than the op pressure needed using only one trol or vstat as a pressure controller (more on that below). High burn gets the system to fill to capacity. The low stage then percolates while system dissipates the btu available in the rads into the room, then high burn will again engage as the pressure drops, etc.

THE only thing is to check the stack temps, but I think if modulation is between 100% and 67% of BTU input (as what LGB boilers are designed to do), this should be fine on LGB as well as any other similar boiler with a draft hood, imho.

FUEL USE:

Modulating system in this way, fwiw, will save on fuel too. My prelim look at the last 2 weeks of 2 staging use, with 20 F outside temp, and comparison of my gas use to the last year on my 'right sized' boiler running off a pressuretrol on the higher pressure but all else equal (with one zone being zoned off or on, at the same rate as this year, and same overnight set-backs), tells me that I am reducing the overall CCF use from about 1,300 to about 900 per month of January/February use. What?! Yes. I had a double take on this too when I looked at our Duke Energy bill from last year. To put this in perspective further, in 2009/10, before we took out the 1,000,000 btu monster (LGB 11), we were at 1,600-1,800 CCF/month use in Jan/Feb and Feb/March! So, how's that looking to you all!?

For the past 2 weeks, I'm getting about 30-31 CCFs use in the 24 hours period (20s-30s outside), with overnight set-back to 66 F, morning rise to 69 F, and another bump to 71 at 3 pm, to back to 66 F overnight at 7:30 pm. I also ran the tstat for one 24 hour period at 69F overnight, as opposed to using the set-back (20s overnight again and similar day temps), and my use went from 30-31 CCFs/day to 41 CCFs for that 24 hour period - with outside temps being similar to the day prior.

Op pressure:

I was also able to lower my op pressure from 12 oz in single-stage to to 8 oz (0.75 to 0.55 psi) in 2-stage. (I also have used 3 big mouths on one quirky main, which I wrote about here and elsewhere, and this 100% improved venting and steam distribution.)

History:

Prior to 2-stage, I started with 8 oz op pressure on the vstat when I got it this fall. Then I went to 10 oz, and then finally had to settle on 12 oz to overcome the oversizing of the boiler with one 500 edr zone off line and to still get steam to the last rad on the other zones when the temps fell into 20s, and while installing 3 big mouths on the main and 2 long risers off that main (mentioned elsewhere).

Using the 2 stage set-up, low-fire stage can now kick in at 8 oz (0.55 psi, as opposed to 12 oz 0.75 psi), and it will kick in at this pressure on both on the full load edr as well as when edr is reduced from 2,000 to 1,500 with only difference being that on the full load (most of 2,000 edrs calling), it takes a long while to get to that 0.55 psi op pressure, while with 500 edr off-line, this happens much much quicker, as is expected.

Operation looks like this:

High-burn, then, this 0.55 psi pressure triggers the low fire. Then the low fire pressure drops to where the high burn engages again (at about 0.1 psi or thereabout - I had to skim the boiler and am still tuning this in, but am happy with high-low-high-low...). This happens a few times before finally, the pressure remains at about 0.2-0.25 psi and the tstat is satisfied.

There is a condensate receiver and feeder pump motor, and this drastically reduces boiler pressure each time the pump fills the boiler. After a full cook and a few of low-high-lows, the low stage stays engaged for the remainder of the heating call. The pressure keeps at 0.1 psi or so, and low stage burn continues until finally the tstat turns off the boiler. This is even after the pump fill of the boiler.

This very operation dynamics tells me that, all else equal without the 2 stage, the boiler would keep burning at 12 oz until tstat is satisfied. Instead, now it down-fires, then modulates, and towards the end of each call, stays in simmer mode at a steady 0.25 psi. This saves fuel, as evident by comparing gas use over the past 2 weeks and last year.

Our boiler:

We have 1975 EDR boiler, LGB 7 (some of you followed what I was doing over the past few months). Boiler is sized with the 33% pick-up, on about 2000 EDR of rads (now a few less, some moved, some being serviced and off line), and I also have 1/2 of mains exposed and 1/2 insulated in the basement as I need the space heated too for classes in the basement.

BTW, I'm able to, incredibly, get the actual vaporstat to run this low burn low psi set-up, and not the Dwyer switch, which I thought I'll have to use.

It would be interesting to see if anyone else out there plays with 2-stage on a regularly sized boiler. I have a feeling they too will see some reduction in energy use to no negative effect on the heating performance.

On the oversized boiler, I have no doubts this is the best scenario to use: 2 stage and percolate, with massive venting on mains and good venting on rads. @Koan , I suggest you look into 2-staging your beast if it's not the time to replace it yet. It may not be perfect, but it may get you where you need to be - you may need to add extra vents to each radiator to improve venting and a little fiddling around with it.

This is, actually, quite incredible - and I'm very gitty over these early results.

Koan

@milanD

It is a great thought, but I don't see that working for me.
For clarification, my system is two pipe, so the venting is only the mains and 2 crossovers.

I think the impediment to me doing this is that the burners in my boiler (and the valve) are not designed to fire at a lower rate like yours are. As a result simply swapping the valve to a two stage and significantly underfiring my burners would bring too many potential risks of inefficient combustion, CO, and chimney temps being too low. Your 2-stage is great - While I think having a combustion test at both high and low fire would be a really good idea, your boiler is designed to operate that way, mine is unfortunately not. In addition, from what I can tell, most 2 stage valves are designed to work with larger set-ups than mine.

Even so, as is I can recover from a 5 deg setback on a 40 deg day without cycling (barely!), Its just that my gas meter ticks off the cubic feet a bit quickly!

Fred

Because my boiler is over-sized too, a couple years ago, I considered installing a two stage gas valve. Thinking it through, at least for my boiler/home, I decided I had a solution, looking for a problem. My system pressure never gets above 2 ounces of pressure except when the outside temps get below zero, which is maybe two or three days a year. I have a vaporstat on my system and I control the pressure, on those days to 12 ounces and I might get one short cycle on a heat cycle. A two stage gas valve would do me no good except maybe for a few minutes on those two or three subzero days. Not enough pressure at any other time to cause the valve to switch between stages. Just my own experiences.

MilanD

Fred said:

Because my boiler is over-sized too, a couple years ago, I considered installing a two stage gas valve. Thinking it through, at least for my boiler/home, I decided I had a solution, looking for a problem. My system pressure never gets above 2 ounces of pressure except when the outside temps get below zero, which is maybe two or three days a year. I have a vaporstat on my system and I control the pressure, on those days to 12 ounces and I might get one short cycle on a heat cycle. A two stage gas valve would do me no good except maybe for a few minutes on those two or three subzero days. Not enough pressure at any other time to cause the valve to switch between stages. Just my own experiences.

So Fred, how is it that your oversized boiler is not building excess pressure? Does it have to do with you having exceptional venting on the 2-pipe system? All the BTU input has to go somewhere... or does your system just heat up super-quickly?

If our boiler stayed at 2 oz, I'd think to do nothing either. I got here by essentially, wanting to delay firing once the pressure builds when one zone is off (although I got it vented really well, I wanted to see if we can delay fire in order to allow pressure/heat to dissipate before refiring the burners - I was still getting some, not much but some, cycling on pressure). Only after looking at this I learned we can 2-stage it with the addition of one more vaporstat. With 2-stage I'm able to lower the overall op pressure to 8 oz (from 12) and use the low-high-low burn to get the system to capacity, then stay at 3-4 oz (0.2-.025 psi) until tstat is satisfied. Basically, 8 oz burn fills the mains, then low-high-low fills the rads, then low keeps the rads warm until tstat says it's good enough.

I still don't like the way tstat is calling heat as it often does not call until the temps really get a little chilly. This mostly happens on warmer days (like today), with a 60F February day in Cincinnati...

MilanD

Koan said:

@milanD

It is a great thought, but I don't see that working for me.
For clarification, my system is two pipe, so the venting is only the mains and 2 crossovers.

I think the impediment to me doing this is that the burners in my boiler (and the valve) are not designed to fire at a lower rate like yours are. As a result simply swapping the valve to a two stage and significantly underfiring my burners would bring too many potential risks of inefficient combustion, CO, and chimney temps being too low. Your 2-stage is great - While I think having a combustion test at both high and low fire would be a really good idea, your boiler is designed to operate that way, mine is unfortunately not. In addition, from what I can tell, most 2 stage valves are designed to work with larger set-ups than mine.

Even so, as is I can recover from a 5 deg setback on a 40 deg day without cycling (barely!), Its just that my gas meter ticks off the cubic feet a bit quickly!

I hear you. That gas meter is a real pest. Just take the thing off... I've been contemplating it...

Good luck figuring out what to do. I think you won't make a mistake with a regular edr+33% pick-up with all off the shelf controls. I am not familiar with vapor systems, yet...

Thanks for responding!

MilanD

Hatterasguy said:

MilanD said:

For the past 2 weeks, I'm getting about 30-31 CCFs use in the 24 hours period (20s-30s outside), with overnight set-back to 66 F, morning rise to 69 F, and another bump to 71 at 3 pm, to back to 66 F overnight at 7:30 pm. I also ran the tstat for one 24 hour period at 69F overnight, as opposed to using the set-back (20s overnight again and similar day temps), and my use went from 30-31 CCFs/day to 41 CCFs for that 24 hour period - with outside temps being similar to the day prior.

Tracking fuel usage without degree days is useless.

Do yourself a favor and track CCF on a monthly basis, precisely. Get a gas reading on the first day of each month. Subtract the gas usage from a month without any CH (July or August).

Get the degree days for that month: www.degreedays.net


Divide adjusted BTU for the month by degree days and get KBTU/degree day. Now, you have something to work with and can track for improvements.

Note that you must input a base temperature into the program to get an output. The base temperature is the value where no additional heat is required. 65F is typical. My own building is 59F. You know you have it right when the KBTU/degree day in October matches January.

Thanks @Hatterasguy! This is another great tool!

I was looking at 24h ccf use against any given outside temp (22 vs 32, etc, -- whatever my phone tells me it's outside at the time I take a morning reading, and then then, I look at what the overnight temp was and jot that down too), then compare the use against similar days to average it out and estimate daily use per given temp... On a 22F overnight and 32 daytime, use is about 31ccf for the 24 h period 10 am to 10 am.

This will be way more accurate, for sure. Man, it's good to know what's out there... I'll be comparing last year's data per my bill reading (3rd to 3rd of the month), and this last 2 months to see if anything is standing out... watch me be disappointed...

Fred

@MilanD , I think it's the result of a combination of things. My system is a one pipe system BTW. There are a number of us on HH that have over sized boilers that don't build pressure. @Hatterasguy has a thread on here somewhere that speaks to them. Most have large drop headers, mine does not have a drop header but does have a very high header, risers (2) are over 42" up with a 5" header, longest main has about 15' of 4" main and then 2.5" the rest of the loop. A total of 5 big mouths on two mains and one branch, (previously had a parade of Hoffman 75's) Total of 700 sq.ft of connected EDR, boiler rating is 866 Sq.ft. so it is well over-sized. The boiler water stays very clean and I use only a couple Steamaster tablets at the beginning of the heating season, if I use them at all. I also think that having big radiators (even though the total EDR is less than the boiler rating) most are probably sized larger than the heat loss in their respective rooms so it's only when temps get to zero or below that they heat all the way across and the radiator vents actually close. I also use no set-backs at all. I did use a 4 degree setback for a number of years and that just killed the system as it relates to short cycling.
When I first moved into this house, the boiler short cycled like crazy, oils in the water, only one Hoffman 75 vent on one main and an old Sarco vent (rated about the same as the 75) on the longest main. Pressuretrol way out of calibration, clogged pigtail, the whole unmaintained scenario.
I don';t know if you've read any of @PMJ 's post but he also has an over-sized boiler that he really makes work for him.

MilanD

Thanks @Fred !