1 or 2 cycles per hour for 1 pipe steam

ChrisJ

Jamie Hall said:

Well, not the only thing. Cedric manages to keep upstairs and downstairs very even in all temperatures, although wind can make some exposed rooms cold. And I have a simple stat (don't laugh, @ChrisJ !) doing the calling... no other gadgets or whizbangs. Keep it simple!

It's ok Jamie.
My exposed rooms don't get cold on windy days because the TRVs open up more. And, they close more on sunny days. And the Ecosteam makes the cycles longer on cold days and shorter on warmer days.




I was running 3" WC the other night due to many TRVs holding radiators back when it was 2 degrees out.

PMJ

Lacking lots of digital data from all rooms in many different conditions how even the heat is is a judgement we all make. @Jamie Hall your position is consistently that whatever improvements can be made by any new tech devices is not worth the cost or the fuss. I respect your right to assume that position. At the same time I submit that few including you have ever actually experienced the improvements possible with natural vacuum assisted steam heat over a long period of time in a residential setting. I have, and as a mechanical engineer have been quite surprised by the both total amount of improvement possible and also that the industry was never interested in that technology after the switch to intermittent fire. The improvements include efficiency, evenness of the heat, far less water consumption, and corrosion reduction. The improvements are so significant that I would not possibly consider returning to the original T87 stat and vaporstat where I originally started 25 years ago. That you are perfectly satisfied with that control system is really fine with me. I do know, however, that it cannot do what I now need done.

Residential steam heat is dying, and in no small part because no significant control improvements have been made for a very long time. This I find disappointing. These systems were never intended to run with radiators oscillating between mostly full and hot then back to room temperature. That is heat swings from a radiant perspective at a minimum that are really not necessary, at least not nearly to the degree they do in most steam heated homes. It needed to be better to have a chance at all to survive.

PMJ

ChrisJ said:

Jamie Hall said:

Well, not the only thing. Cedric manages to keep upstairs and downstairs very even in all temperatures, although wind can make some exposed rooms cold. And I have a simple stat (don't laugh, @ChrisJ !) doing the calling... no other gadgets or whizbangs. Keep it simple!

It's ok Jamie.
My exposed rooms don't get cold on windy days because the TRVs open up more. And, they close more on sunny days. And the Ecosteam makes the cycles longer on cold days and shorter on warmer days.




I was running 3" WC the other night due to many TRVs holding radiators back when it was 2 degrees out.

Sorry, I left out Ecosteam which was a significant control improvement. The market didn't support it apparently which is my point. I think it would have taken considerable pushing by the pros to get owners to try it. It would have been worth it all around. Great control, everyone would have been happier with a lot of them out there. Maybe too complicated/expensive? I don't know. But something more than tstat/vaporstat was needed a long time ago.

Canucker

I love the fact that we explore many different paths to the same goal here, when it comes to hydronic heating. I love the simplicity of the system @Jamie Hall has and the balanced control that @ChrisJ and @PMJ have attained through different paths. They're like little steam experiments that fascinate me and give light to solutions based on different circumstances. Keep it coming gentlemen.

PMJ

Curious_J said:

@PMJ What type of control system do you have?

2 pipe originally Mouat system. I do my own custom control. Started with simple delay timers, now a Teco PLC - the same one that is in Ecosteam. It is about $100. Software free. Once installed you are free to develop your own logic. I just keep tinkering with it. Still learning things. Steam is really cool stuff.

mroberts5

Is anyone doing pressure control via a pressure transducer and a modulating gas valve? Run a PID loop with a few simple limits. Seems simple enough...why isn't this a thing?

KC_Jones

mroberts5 said:

Is anyone doing pressure control via a pressure transducer and a modulating gas valve? Run a PID loop with a few simple limits. Seems simple enough...why isn't this a thing?

@MarkS would you like to answer?

Jamie Hall

Trick is to keep the air/fuel ratio correct while you're varying the gas pressure. Not quite that simple...

mroberts5

After a week or so running on 3CPH, I have noticed balance issues. The radiators nearest the boiler are heating up much more than those farthest. And yes, I have what I think is ample main venting (big mounth on 40' of 3" main).

> @mroberts5 said:
> On an oversized boiler I'm cutting in and out on pressure at the end of my cycles (running Vaporstat). Reading this got me thinking.
>
> I tried switching from 1 cph to 3. Now the boiler never makes it to pressure. Overall the system is much quieter and the temperatures seem more even. Whats interesting is the radiators never even heat all the way across now - so the vents don't even see steam. Seems like a win?
>
> What are all your thoughts on how this affects efficiency: running once per hour then cycling on pressure, vs running 3 times per hour, for a single run.

Jamie Hall

"After a week or so running on 3CPH, I have noticed balance issues. The radiators nearest the boiler are heating up much more than those farthest. And yes, I have what I think is ample main venting (big mounth on 40' of 3" main)."

Not surprised. Even with ample main venting, steam does not get to all radiators at once -- much as we might like it to -- and the cycle is too short to allow adequate steam to the farthest ones. Lengthen the cycle.

PMJ

This is where vacuum absolutely steals the show and evens out the delivery times to all rads. Trying to move all that air just the "right" way every cycle will never be close. Overfill every burn becomes the only choice. Oh well. No point in working on that either I suppose.

ChrisJ

All of mine still heat evenly regardless of how short the cycles are.

Slow the venting on the closer radiators and speed up the further ones. It's that simple.

If need be, vent the runouts to the radiators. Mains aren't the only pipes that need to get air out.


Thermostats do not cause balance issues. Balance issues do.

PMJ

ChrisJ said:

All of mine still heat evenly regardless of how short the cycles are.



Slow the venting on the closer radiators and speed up the further ones. It's that simple.



If need be, vent the runouts to the radiators. Mains aren't the only pipes that need to get air out.





Thermostats do not cause balance issues. Balance issues do.

I have to agree with you here in principle @chrisj. Shorter cycles will also force one to do a better balancing job. Lots of moving parts in one pipe but once there a quite good result as you have shown. No pressure required either as you demonstrate.

Mark N

@ChrisJ, what determines how long your boiler runs when the thermostat calls for heat? I would think it’s the Ecosteam. If that’s the case, your thermostat can turn off but your boiler keeps ruining until the Ecosteam is satisfied. If you have only a thermostat set to 3 cph, the boiler will turn off.

ChrisJ

> @Mark N said:
> @ChrisJ, what determines how long your boiler runs when the thermostat calls for heat? I would think it’s the Ecosteam. If that’s the case, your thermostat can turn off but your boiler keeps ruining until the Ecosteam is satisfied. If you have only a thermostat set to 3 cph, the boiler will turn off.

The opposite. The Ecosteam can interrupt the Thermostat but if the thermostat turns off the boiler shuts off.

99% of the time the Ecosteam shuts the boiler off and the thermostat stops calling 5-10 minutes later.

Mark N

@ChrisJ, thanks I had it backwards. What cph setting are currently using?

ChrisJ

> @Mark N said:
> @ChrisJ, thanks I had it backwards. What cph setting are currently using?

I use 2. I've tried just the thermostat with 3 and it worked ok, but it's a lot better with the Ecosteam even set to 2.

Mark N

I've tried 2 CPH with my FocusPro5000. The results were less than satisfactory.

mikeg2015

PMJ said:

Residential steam heat is dying, and in no small part because no significant control improvements have been made for a very long time. This I find disappointing. These systems were never intended to run with radiators oscillating between mostly full and hot then back to room temperature. That is heat swings from a radiant perspective at a minimum that are really not necessary, at least not nearly to the degree they do in most steam heated homes. It needed to be better to have a chance at all to survive.

No it’s dying because most homes add central air, and you can drop in a furnace for a relatively small increase in cost and poorly maintained systems have pipe leaks, valves need repacked, traps, vents, etc. They need to be repitched... you all know the drill. Steam boilers are expensive and contractors often fear them too. Better to make as much profit selling 3-4 furnaces than one boiler. Both take the same labor.

For installed cost, under and in floor radiant are cheaper than hot water wall mount radiators in new homes.

Jamie Hall

I realise that this is likely to be taken as heresy, and I'll be drummed out of the corps, but... first, for new construction there really is no good excuse not to use semi-active solar principles, which can achieve very close to 100% solar heating for a residence pretty much anywhere south of Edmonton. Second, If you don't want to go to the difficulty of the engineering and architectural solutions for that, there is much to be said for a quality forced air system, using heat pumps as the primary heat and cooling source. Not to say that there's an awful lot of pretty horrible forced air out there, but if truly done right...

It's when one gets into upgrading older buildings -- or even maintaining them -- that we get interested in the best or most feasible way, consistent with expense, historic preservation, and all that, to do the job.

gfrbrookline

Update on original post.

I recently had 40' of asbestos replace on 10' of main and 30' of returns with 1" insulation. I also replaced about 30' of 1/2" insulation with 1" insulation on the mains and insulated my header and joints.

This of course totally screwed up the balance in the building so I moved vents around on the mains and then re-balanced the radiators. I can now run on 2cph with the vaporstat set to run between 12oz and 6oz without cycling and the heat is much more even with temps in the teens. The pipes stay warm and the on to steam time is much reduced. Yes the rads do not always heat through but they provide enough heat to keep the room heat at the correct temp.

Inliner311

Another setting that should be adjusted with CPH if you have it is minimum on time. I know some Honeywell thermostats have this. It will basically give you the option to only turn on the boiler if the thermostat calculates you need a certain amount of minutes of heat. So if you have it set to 5 minutes the boiler will only turn on if the thermostat calls for 5 minutes or more of heat.

I think this is important especially for steam because if your boiler takes 3-5 minutes to even make steam then there is no point to have it turn on to make 2 or 3 minutes of heat.

ChrisJ

Inliner311 said:

Another setting that should be adjusted with CPH if you have it is minimum on time. I know some Honeywell thermostats have this. It will basically give you the option to only turn on the boiler if the thermostat calculates you need a certain amount of minutes of heat. So if you have it set to 5 minutes the boiler will only turn on if the thermostat calls for 5 minutes or more of heat.



I think this is important especially for steam because if your boiler takes 3-5 minutes to even make steam then there is no point to have it turn on to make 2 or 3 minutes of heat.

An older meme of mine....

Zipper13

another consideration is that I've also found that my honeywell stat set to "steam" which I believe aims for 1 CPH appears to lie to me. I'm mostly OK with it as I'm comfortable and have found savings since the swap out, but if set it to "65" it will show 65 as the room temp, but my collection of older stats and in the same room will show sometimes as high as 69 a the end of a burn. and the opposite thing on the low side... it will show the room at temperature if it hasn't decided to call for heat yet, even if the other thermometers in the room are showing 63 or 62. I'm fine with these swings, though since the net effect of moving to 1 cph was more even distribution throughout the whole house since ALL the rads now get heat as opposed to before when only the front half of the house heated for the whole cycle and the back of the hose got half the cycle (since the stat is in the same room as the first three radiator in the [uninsulated] loop).

Perhaps 2CPH would reduce the temperature swing and the degree to which the stat "lies to me"

mroberts5

To give some feedback after running 3cph for two months: I'm still quite happy with how this has quieted down my oversized systems (mostly quieted down vent noise). It *feels* like it's running too often and for too short of of a time, and I'd like to try 2 cph but still have to find a thermostat that'll do that. Only thing I've noticed is my basement is quite a bit warmer than it used to be. Running more regularly is probably keeping the boiler and pipes near operating temp for longer. I live in a one story house so it's not all lost, but probably is slight less efficient. The gas usage was up, but only a few cf so it's not much. Worth it for the noise reduction.

ImYoungxD

This thermostat at Homedepot is $10 with free pick up from store. It has 2 CPH but no 1 CPH

https://www.homedepot.com/p/Honeywell-5-2-Day-Programmable-Thermostat-RTHL2310B/308033062

mroberts5

Awesome. Out of stock , but on ebay. I'll report back.

PMJ

mroberts5 said:

To give some feedback after running 3cph for two months: I'm still quite happy with how this has quieted down my oversized systems (mostly quieted down vent noise). It *feels* like it's running too often and for too short of of a time, and I'd like to try 2 cph but still have to find a thermostat that'll do that. Only thing I've noticed is my basement is quite a bit warmer than it used to be. Running more regularly is probably keeping the boiler and pipes near operating temp for longer. I live in a one story house so it's not all lost, but probably is slight less efficient. The gas usage was up, but only a few cf so it's not much. Worth it for the noise reduction.

Wouldn't you like more options than 1,2,or 3 CPH? With a simple duty cycle delay off/delay on timer you can have unlimited choices 1.3 CPH, 2.7CPH...... anything you want.

Great to see someone observing the benefits of spreading out the firings into smaller pieces - especially when you are oversized.

Also, my experience has been that the time to steam reduction with more cycles on a boiler with an automatic damper is so significant that it ends up being more efficient.

mroberts5

If I didn't have other hobbies I'd get a micrologix plc and an rtd.

PMJ

mroberts5 said:

If I didn't have other hobbies I'd get a micrologix plc and an rtd.

Understood. It has been my hobby for a while and I do use a PLC. I hope you can work it in sometime. Adjusting the performance from the computer. Your latest idea is just a few keystrokes away. All previous ideas stored as programs that can be returned to at any time. Fun stuff.