TRVs / Boiler Pressure settings

SFbird

Hello again! Yesterday our Homeowners Association finally installed TRVs on all the radiators in our 12 unit, 1929 building and our plumber is coming back in about 10 days to install a new Honeywell boiler control/thermostat on the boiler. We have a one pipe steam system, boiler new in 2011, Peerless 64-08s 399k BTU. Our previous plumber has had the system operating on just a timer that we have adjusted manually when the outside temp changes drastically. Idiotic, yes, but it seems to take forever to get things done over here. After much (very helpful) back and forth in 2011 on this site, I finally got that plumber to lower the boiler pressure to about 1.5-2 psi ( he had been running our previous boiler at like 5!).
I am wondering if we still need to go lower. The radiators in my unit ( furthest from the boiler, three floors up) are still getting warm when the TRV is set to lowest setting/off .They go from just a bit warm to very warm after the boiler runs for a couple of hours. We are using Danfoss 013G8250+013G0140 and hoffman 41 vents. Do you think this can be resolved once we get the proper thermostatic control on the main boiler or should we be drastically lowering the pressure settings as well? Right now the boiler runs twice a day for about 4 hour stretches and that is probably part of the problem.

Abracadabra

On a small building such as yours you shouldn't need much more than 1psi. With TRVs installed, the boiler may now short cycle. You may wish to ensure you have a hi-lo fire setup installed with a vaporstat. Boiler really shouldn't need to run a 4 hour long cycle. I don't think I've really had a boiler fire for more than an hour per cycle. Maybe 1:15-1:30 when recovering from a setback.

New England SteamWorks

SFbird said:

The radiators in my unit ( furthest from the boiler, three floors up) are still getting warm when the TRV is set to lowest setting/off .

What size vents are on your radiators?

Did you get the TRVs with a vacuum breaker?

If yes, the packing on your radiator valve might be leaking steam.

Bill_17

The lack of cycling is the logically the primary problem as one pipe steam TRVs need cool down cycles to bring air back into the system for control reasons and a long on-cycle prevents that. In addition, the pressure is probably still higher than necessary. More information on the control that will be installed plus how it functions and where it is installed will indicate if it is the right approach. A 4 hour run time is extremely long, even in the coldest of weather as these systems tend to be way oversized to the load.

SFbird

RI_Steamworks: the vents are Hoffman 41, The Danfoss TRVs have a 1PS valve (o13G0140) and the Thermostatic Operator (013G8250)


Bill: I hope I don't sound like a complete idiot as I am not a plumber- but when you refer to cycles do you mean the time the boiler is turned on ( in our case with the timer that starts it up at let's say 5pm and keeps it on until 10pm) or when it actually fires up ( burner lights and then goes off again, at intervals)? I would need to go down there and watch it to see how long those intervals are.

Will having an actual thermostatic control on the boiler resolve this if our four hour run time using the crappy basic timer is what's messing with the TRVs? I am going get the pressure down as you advised and also see about a gauge with lower settings than what we have now.

My plumber is suggesting a Honeywell thermostat for the boiler, I need to get the specific model number, all I know is that it's $300 bucks. I've had folks here recommend Tekmar units as well. We haven't bought anything yet so I'm open to suggestions on which model of either brand to use. The installation isn't going to happen for at least 10 days so do we need to shorten our boiler "on " hours until then so we don't mess up the TRVS? Also don't want all the owners here going nuts because their apartments are overheating. It has been in the 50's and 60's here ( SF, CA).

KC_Jones

Did you put TRV's on every single radiator in the whole building? If so I don't see how you can really use a thermostat...ever. You can't put a TRV on a rad in the room with the thermostat as they will fight each other. Also with TRV you need to cycle the boiler regularly so the TRV will work properly. When the TRV closes and the boiler is still firing the rad will continue to heat since the steam will condense cause a small vacuum and pull in more steam. This will happen until the boiler shuts down. Then all the system steam collapses the vacuum breaker on the TRV opens and fills the rad up with air instead of steam. On the next cycle if the TRV is still closed no air gets out so no steam gets in. A thermostat is on or off it turns on until you reach temp then shuts down. IMHO a Tekmar or similar would be a better choice in your situation, BUT you are talking about a lot more money (we don't discuss pricing here). I would be very careful with all of this as it almost sounds like your plumber isn't aware of any of this. If he isn't familiar with controls and how to set them up it would be good to either educate yourself or find someone that knows.

SFbird

KCjones: We haven't decided on a boiler control or thermostat for the boiler and still have time to decide what to do. We put TRVs on all the radiators in the building yesterday except one unit that we didn't gain access to yet ( two radiators in there that we'll get to in a week or so). From my understanding we wouldn't be putting a thermostat in a room where a TRV is; we really need a sensor to read the outside air temperature and have it adjust the boiler time so we could avoid having the boiler come on or stay on too long when it's above a certain temperature outside. We don't want to manually adjust the hours when it dips below 50 for a week at a time either. We don't see very many temperature extremes here ( San Francisco) but there is a sort of damp chill that results in our running the heat year round. It is rarely below 45 degrees in the winter or above 75 in the summertime.

The timer we have on the boiler now can only be set to turn the boiler on 2x a day, I need to know how long it's okay to run the boiler for now with the TRVs in place until we get a better control installed. I only mentioned the price of the Honeywell because I don't have the exact model our plumber was recommending and thought the price range might be an indicator of what model it might be to those of you that are familiar with what they sell. I really appreciate the help; it has been pretty frustrating dealing with some of the plumbers out here ( see my horrifying thread from when we replaced the boiler in 2011)- The only way I resolved a nasty steam hammer problem was by listening to everyone in this forum! I ended up buying one of Dan's books and giving it to the plumber we had been dealing with- the guy who had our boiler operating at 5 PSI.

SFbird

Thanks Hatterasguy! We will look into it. We are not afraid of spending more money if we can just get this system running right! We had looked at a Tekmar ( can't remember the exact model) and the price wasn't scaring us so much as our concerns about ease of operation.

KC_Jones

http://www.twotwelvef.com/
Try this link, similar to what Hat posted. Contact @MarkS and he could help you to decide if it's a good fit for you. I have one in my house and love it.

SFbird

Are we in any danger of damaging the newly installed TRVs before we get a boiler control on there by running the boiler for 4 hrs at a time? Do I need to find another installer who can get this done in less than two weeks?

nicholas bonham-carter

I think that, when the system is properly balanced, with good venting, and proper controls, the apartments with removed radiators will be too cold, rather than too hot.
If the new system control, and main vents had been put on first, and set for constant operation, rather than off and on, then the TRV's would not have been needed.--NBC

Bill_17

I think the majority of your questions have now been answered, but in general a steam reset control (outdoor reset) is superior to a conventional room thermostat in most buildings that are larger than a 1 or 2 family home. Specifically relating to your question about "a cycle", I'll define it as the time from an initial call for heat until the outdoor reset control or conventional room thermostat is satisfied and the boiler is turned off until there is need for additional heating. With a "timer" on a 1 pipe steam system, you do get a cycle. But, because the timer runs for a fixed time it is totally unrelated to the actual need for heat and rooms will eventually overheat, not to mention that you are wasting fuel. Feel free to call us (Danfoss) @ 866.375.4822 if you would like to know more.

SFbird

Thanks so much for all the help! I sent a message to MarkS to see if he can help me identify with appropriate Eco-steam controller to get. I've asked our plumber if he is familiar with them but am waiting on an answer. I don't know where MarkS is located (or if he is a contractor) but I'm open to suggestions for SF Bay area installers. Just want to get this right and so far have had too many confusing messages from various plumbers out here!

JUGHNE

ElisabethinSF found a wallie in SF in her "2-pipe conundrum in SF" posting of 2-18-16. He had even been to Dan's Seminars.

nicholas bonham-carter

Here is the link to that post, so that you may email her directly for his name:
http://forum.heatinghelp.com/discussion/comment/1417862/#Comment_1417862

SFbird

Excellent ! Thanks. I sent her a message.
My husband is having the person who installed the boilers for a property he manages ( 29 story ,1929 landmark building downtown) come out next week to give us his two cents on what we need. He knows about the EcoSteam but suggests that we could get away with some less sophisticated controls. Will keep you posted!

nicholas bonham-carter

The problem is not with the controls, but rather with the whole steam system. No control can accommodate a badly balanced system, so you have to solve that problem first. This solution includes the main venting- is it adequate? One little vent will not work. The air has to escape from all the pipes first, and quickly with no resistance. Following that, the steam will then rise up into the radiators, simultaneously, pushing the last bit of air out of the rad vents. The result should be that all the radiators receive steam at the same time, making everyone comfortable.
The need for TRV's would be useful for one or two over heated rads, at the most, in most systems.
You really need to get this system working right, as the TRV's are not the final solution, and have been a waste of money so far.
When this building was built, with its steam system, the variations of temperature you are experiencing would not have been tolerated, and the installer would have been sent to San Quentin straight away, (along with the later knuckleheads who have worked on this).
Unfortunately, the possibility of sending back the TRV's is not possible, due to the old valves having been disposed of.
What an unfortunate waste of time and money!--NBC

SFbird

Thanks Nicholas, I understand what you are saying. The system isn't the horrible state it was in back in 2011-12 when we had to replace the boiler. With your help and the help of others here, I got our plumber to add Gorton 2's to the mains in three spots that were accessible. They are all at garage level (which is where the boiler is) and the only other place I think we might benefit from adding more would be at the top of the risers (?) but there is no evidence that the system ever had vents at the top floor level and I don't know how we would even access those areas. If you think we should put more in the garage I am open to doing it. We are going to recheck the pressure settings when this new heating guy comes out for a walk-through Monday; the cut-in is set at .5 right now if that means anything, I don't know what to look for when the boiler is actually firing. I found the source of our big steam hammer nightmare in 2013 with little help from the previous plumber; I had to make him open up part of the ceiling near our boiler where we found a rerouted steam pipe that was configured into a flat bottom "U" shape during seismic upgrades to the building by some idiot who didn't realize they were creating a giant water trap.

The system has been quiet since then for the most part. Most temperature imbalances from unit to unit are mainly on the first floor because the mains run under their floors. We had a lot of the piping insulated but those 4 apartments on that level tend to be the warmest. Any noise we get is from when an individual owner improperly uses a service valve to control the heat in their unit. That is why we looked into TRVs in the first place along with getting a real control and possibly some kind of thermostat on the boiler. We don't want to run it for three to four hour long stretches at a time, we are wasting tons of energy.

RJ_4

auto control of 1 pipe steam systems Feb. 2012

SFbird

Thanks RJ. I read the Danfoss info you posted and am understanding this better now. The guy that is coming out Monday is recommending that we run the boiler for maybe 30 minute intervals. He hasn't looked everything over in person yet but is that sounding like it's more reasonable? He is familiar with the EcoSteam system but also said we might be able to accomplish what we need to do with a less sophisticated boiler control. MarkS seems to agree.