Is this short cycling?

anthonybsd

Hi there,

Long time lurker, first time poster. We recently bought a really old colonial in Montclair, NJ. The steam heating was in a complete disarray (no maintenance in likely 6-10 years by previous owners). Seized/solidified pigtail, glitchy low water sensors, a mess of wires to the thermostat, leaking valves everywhere, etc.. All of you plus "Art of Steam" ( thank you Dan!) helped me enormously, so thank you!

I just about got it all tuned in and running fairly smoothly. No banging anywhere, near silent heating of radiators, every radiator heating at the same time (a minute roughly from system kicking in), 0.5 cut in 1.5 PSI cut out on the Pressuretrol. However, I was in the basement doing some work today and observed my boiler heating cycle when thermostat activates it and I wonder if what I have is considered short cycling. Going from cold - thermostat activated the boiler, it ran for about 2.5 - 3 minutes, then pressuretrol cut it out. It sat for about 40 seconds then activated again and ran for 1 minutes then cut it out. It then cut in again and ran for about 2 minutes and then cut out and at this point Thermostat was satisfied. In other words:

From activation:
- 3 minutes
- 40 sec pause
- 1 minute
- 40 sec pause
- 2 minutes
- Done, rooms heated

Does this look like a short cycling system? If yes, does that mean I have an issue with air being trapped somewhere?

Jamie Hall

That cycling that close to the beginning of a relatively short heating cycle certainly suggests that the main venting is inadequate (that really isn't trapped air in the same sense as one might say for a hot water system). What, if anything, do you have in the way of vents on the main steam lines?

It could also be a result of a really wildly oversized boiler -- but let's answer the question on main vents first.

Gsmith

Also what type of low water cut off do you have? Picture?

anthonybsd

>What, if anything, do you have in the way of vents on the main steam lines?

Ah, so I suspect that might be my issue. After reading the book I tried to locate my main vents but they simply look like they are not there. I found two locations where I suspect they might have had vents before but they are plugged/sealed now (pictures below).



Does that look like it?

So basically what I likely have is air not able to escape fast enough (because only vents are radiator-ones) pushing back the steam thus resulting in rising pressure?

anthonybsd

Gary Smith said:

Also what type of low water cut off do you have? Picture?

Picture attached:


I think it's a pretty standard one. I know for sure the boiler is shutting down due to pressuretrol and not the water level because the low water cutoff red light doesn't go on (I've tested it in the past).

Fred

In addition to what @Jamie Hall said about needing Main Vents, which you really, really do need, do you have a digital thermostat? If so, is it programmed for steam at 1 cycle per hour? They come from the factory with a default setting for forced air at 5 cycles per hour. It sounds to me that you are cycling on the thermostat rather than pressure (no boiler is going to build enough pressure to trip the pressuretrol in one or two minutes on a cold start, be it over sized or a lack of main venting.

Program the thermostat AND get some main venting on the system. Those two capped/plugged pipes in your pictures look like old radiator run-outs where radiators may have been removed but they will work for vents if they are at the end of the mains.

Gsmith

Is this a 1-pipe system?
If it's a 1-pipe system (only one pipe to each radiator, not two), then look for vents after the radiator supply pipe off the each main that is furthest from the boiler. That's where your main vents should be. (Sometimes they are on the ends of the dry returns near the boiler, but not usually). If no main vents on the steam mains or returns, then that is probably your problem.

anthonybsd

I do have digital thermostat. Ecobee 3. I researched a number of them and consensus here seems to have been that it’s steam heating friendly. I haven’t been able to find cycles per hour though. It certainly seems that it fires no more than that during even the coldest days.

Fred

I don't think the Ecobee has a cycle setting and I don't think the consensus here is that they are the best thermostat for Steam.

JohnNY

It sounds like the boiler is oversized. Those plugged 45° take-offs from the main aren't vent tees, they're branch connections. I'm guessing that removing the branches and their connected load created the oversizing...or something to that effect. That looks like a builder's grade boiler with the ignition controls all mounted exposed outside the jacket which never inspires confidence in the installer.
More pictures, please, or call me for a full system evaluation. I've got a shop in Orange, NJ and one in Manhattan and I deal with steam heating systems all day long, whether I like it or not.

anthonybsd

> @Gary Smith said:
> Is this a 1-pipe system?
> If it's a 1-pipe system (only one pipe to each radiator, not two), then look for vents after the radiator supply pipe off the each main that is furthest from the boiler. That's where your main vents should be. (Sometimes they are on the ends of the dry returns near the boiler, but not usually). If no main vents on the steam mainsta or returns, then that is probably your problem.

Yep it’s a 1 pipe system and as best I can tell vanilla one, ie not a countwrflow one. Pictures above show what I think might have been original vents at 1) wet return and 2) furtherest point of the main that is still in the basement.

Jamie Hall

Fred said:

I don't think the Ecobee has a cycle setting and I don't think the consensus here is that they are the best thermostat for Steam.

At least they're not as bad as a Nest. But on looking through the available literature, they only seem to acknowledge the existence of forced air -- so there may well not be a way to handle any high mass system.

Honeywell makes some really good thermostats -- 8000 and 9000 series -- which do the same sorts of things better; just not as sexy.

EBEBRATT-Ed

@anthonybsd

getting @JohnNY to look at this would be well worth it for you!

could be:
venting or lack of venting
oversized or over fired boiler
unstable water line tripping on low water cutoff

Those are the three most likely culprits

SuperJ

The ecobee does have some min timing options, no cycle per hour, but I doubt this problem is thermostat related. Sounds like it's cycling on a safety, I would be surprised if the heating call was dropping out from the thermostat. I bet it will do the same thing if you crank the ecobee up a couple degrees to guarantee a long run call.

ethicalpaul

Welcome, neighbor! I went through exactly the same thing when I bought my Cedar Grove house in 2017. Your boiler setup and brand also looks very similar to mine (Utica?) and we may have had the same installer (in the early 90s) who apparently was OK with missing main vents. Mine was capped off and easy to restore. See https://forum.heatinghelp.com/discussion/167241/no-main-vents

If Dave is too busy and you want help looking for your main vent locations or you need a hand lifting a radiator or something, let me know!

And @Dave0176 if you want to do two consults in one trip up this way, I can make myself available any time. I need a combustion check, a look at a couple of safety controls and a general lookover.

EzzyT

Most likely the boiler is oversized and lack of main venting as others have mentioned. I also doubt the boiler is piped right.

anthonybsd

Update: did a lot of poking around on Sunday and finally found my main vent. There's only one on the wet return line. It seems to have been painted over heavily and doesn't appear functional. I'll try swapping it for a new one this weekend and see what that yields me. Thanks to everyone who contributed.

ImYoungxD

anthonybsd said:

Update: did a lot of poking around on Sunday and finally found my main vent. There's only one on the wet return line. It seems to have been painted over heavily and doesn't appear functional. I'll try swapping it for a new one this weekend and see what that yields me. Thanks to everyone who contributed.

Most of us would suggest Barnes and Jones Big Mouth. Amazon sell those.
Next would be Gordon #2

Koan

I replaced my Gorton #2 with a Barnes and Jones BM3 to help my short cycling. It worked well for me. The vent should, however , be on the dry return (the part above the boiler water line) not the wet return (the part below the boiler water line).

anthonybsd

Koan said:

The vent should, however , be on the dry return (the part above the boiler water line) not the wet return (the part below the boiler water line).

In that case I think I'm confused. In my case it is the pipe that's above the boiler waterline, but doesn't condensate flow through it back to the boiler? In my case I don't have any pipes that go into the boiler from below the boiler.

ethicalpaul

You are OK—the same return pipe is called the "dry return" where it is above waterline and "wet return" where it drops below. Confusing I agree

You'll see the normal waterline of the boiler is some distance above the lowest return pipe (I would hope--unless it's a counterflow system, but I have a lot less personal knowledge about those).

anthonybsd

Update:

Thanks for all your help. Replaced the old (circa 50s - 60s?) vent with Big Mouth which in itself was a bit of an adventure. Had to saw off the old vent and cut the thread. With BM installed, boiler now stays put for a very long period (15-20 minutes) before the pressure begins to rise, so mission accomplished.

One small issue I've encountered though - it seems that after Big Mouth membrane closes, it intermittently lets out a bit of steam at regular intervals, enough to produce condensate to drip down (picture attached). Is that normal modus operandi, or does it need a few days to break in and to start sealing properly?

Fred

That is not normal. Is the Big Mouth tilted in any way? If it is not level, it may hold a little water that may cool it enough to open it intermittently. It looks like it is on the end of a return, which in and of itself is pitched down. If you can, turn your 45's so that the Big Mouth is perpendicular to the pipe and level it up. That should fix the problem

gfrbrookline

It should close tight once the steam hits it and stay that way until after the system cools down unless it encounters water.

Try turning the new piping so it is parallel to the return add a 90, a 6" nipple and another 90 and mount the big mouth on that. If you have the room I would also add a bit more height off the return as well. Getting it away from the return drop may help protect it from water and running it parallel will let it drain.

anthonybsd

Thanks Fred. It looks fairly perpendicular to the ground overall (see pics) so I don't know if that is the issue. Pics attached. Since I can't stick a full length level there I just duct taped portable one:





If pitch is not the issue could my BM be defective in any way?

Jamie Hall

Probably not -- if it isn't being held closed by steam, but condensate gets in there, it will spit a little.

Ying

@anthonybsd wondering how the main vent is working for you so far. In a situation to add a main vent to my system and looks like a good option for me is also somewhere on the wet return pipes. Will you be able to post a zoom out picture of the pipes that you put the main vent on?

See pictures of my wet return pipes here
https://forum.heatinghelp.com/discussion/comment/1544733#Comment_1544733
And my propose main vent installation idea a few comments down. Wondering how similar or different is it from yours.

Has the "intermittently lets out a bit of steam at regular intervals" issue gone away. That will be my concern too as the wet return pipes gets colder faster then the main pipes and that might cause the main vent to open due to the cooling and then steam gets it hot again to close.

And how are the cycle times so far with the new main vent.

anthonybsd

@Ying The new main vent is working fairly well. Besides the slight aforementioned spitting issue Big Mouth drains the air out of the mains very quickly. After I played with rotation, etc. it is less of a "steam escaping" and more of a "slight spitting" during heating cycle. I think I might add longer piping to it to eventually sort it out - it doesn't really bother me that much except for a slight perceived water loss. I think actually a few of the older remaining radiator vents (the ones that I haven't changed yet to variable Hoffman 1A) contribute more to some steam escaping than the Big Mouth. I'll post a zoomed out picture of the pipe with vent mount when I get home.

Anyhow, onto the original issue - cycle times have become more regular and longer. Before the pressuretrol would kick in within 10 minutes or less of the heating cycle starting from cold. Now the pressure stays less than 0.5 PSI for at least half of the cycle that thermostat is calling for. Heating cycle for a day looks like this:


Since I'm a data geek I'm now trying to tweak my thermostat in terms of when it kicks in (temperature delta) and how long it stays on after activation (currently at 20 minutes) and correlate it with actual boiler run times (wired a timer clock into 24 volt from pressuretrol to the boiler), mean outside temperature for that day, and finally number of therms used (just for good measure). I started plugging this into spreadsheet to see if tweaking any of these variables results in any therms savings for me. It's sort of a longer term project

ChrisJ

I haven't installed the Big Mouth I have yet, sorry Peter. I've been so busy that I never have time for much of anything. I've had it for a few seasons now, so that's pretty bad on my part.

But, with the first one I tested I didn't watch it close enough to know if they open occasionally in normal use.

That said, to me it seems perfectly reasonable for this to happen. Especially if the surrounding air is cold. If steam is condensing in it perhaps pockets of air work their way out of the system and hit it, or cooler condensate trickles down on the capsule and causes it to open.

Ying

@anthonybsd Thank you very much. Really appreciate it. As it will be really cold for the next month, was thinking about waiting till March to do all the replacements.
Going change out many parts on the boiler after I skim and clean everything, so that if I do break anything, weather won't be so bad if say boiler is out for a night.

As for the above the data graph above, it is the cycle for the thermostat correct? When I calls for heat to turn to boiler on and off. Was more interested in the cycle of boiler firing up and then off, how long and how often it takes till the pressure cuts the boiler on and off.

Thanks again for the help.

@ChrisJ what you are saying makes sense to me, as the main will be all the way in the front of the house for me, in the meter room where we don't usually go to, so bare minimal instillation. Average temperature is about 55-58 there. Guessing if I put a main there, it will behave the same way due to the air temperature in the room. Just want to rule out the reason for the opening being condensation returning through the we return