What TRV & Thermostat options do I have with this setup?

bad_habit

Hi folks,

My NYC coop has these steel convector radiators which heat up to impossible temperatures and make living hell in the winter. They are quite old and have manual valves which can be turned by hand to shut down the radiator (only one of them works unfortunately in my apartment). I'd like to know whether I can install a thermostatic radiator valve (TRV) on such a radiator, replacing the manual valve and if yes, could you recommend any brands that I can potentially use with a nest thermostat?

nicholas bonham-carter

What is the temperature in your space, measured with an accurate thermometer?
If that building has always been apartments, and the system is original to the building, then it would have been designed, and installed so that the inside temperature would remain at 70 degrees.
This situation of superheat leads me to believe that the system is unbalanced, and running at too high a pressure. Perhaps 30% of your collective fuel is being wasted. Whatever controls the boiler may be at fault as well.
Ask the management when the last time any general system maintenance was performed, and what pressure the boiler is set to, (should be under 8 ounces). Also ask how the heat is controlled, and post the answers here. There are a number of excellent NYC steam professionals, listed here on the find a contractor button, and they will have more knowledge than regular plumbers, (who supply a different type of comfort).
Judging from one of your pictures, it does not look to have been recently looked at by a true steam expert, with all the blue tape sticking out from the trap cover. The valves could be fitted with new washers, if needed.--NBC

bad_habit

Thanks Nicholas. Here's the thing. The temp is generally 80F in my apartment in the winter. The building will not make changes to the heating system. It's a coop with 400 units. Trying to change their opinion or make them do something is like trying to convince a city official to move an airport. I tried, believe me. My only option is to do something directly at the radiators in my unit. This is why I am looking at options to replace my manual valves with TRVs.

MilanD

This is a 2 pipe system with a trap. Only thing you can do is fix the valve and allow it to regulate amount of steam into the rad. Trvs in steam generally refer to vents, and your system doesn't have a vent. Trap acts as a vent. That said, there may be thermostatic valves that can replace the current manual valve. Perhaps something like regular water radiator valve would work here. See this: http://www.supplyhouse.com/Honeywell-Braukmann-V110E1012-3-4-Angle-Valve-for-High-Capacity-Radiator-10854000-p

Poke around there for "thermostatic radiator valve". There are various brands making this setup. Although this is for water, it may work for the 2 pipe system you have.

You will also need a remote mounted thermostatic actuator to get it outside the convector box. See this: http://www.supplyhouse.com/Honeywell-Braukmann-T104B1038-High-Capacity-Thermostatic-Radiator-Actuator-remote-sensor-10860000-p

I'd venture to guess this would work for you quite well. It's not the Nest or Wi-Fi, but it would work just the same.

Lastly, you need to have a qualified steam person look into the system operation, and that is at its optimum setup. Someone must be maintaining it and you want someone who knows steam. With changes NYC is instituting with heating systems city-wide, you may soon get a qualified tech company. But, someone definitely needs to double check the system is tuned up to its optimal op setup.

Good luck!

Abracadabra

Throw some insulation on those convectors. Will significantly reduce their output. Cheap, quick, easy fix

Fred

I would suggest you get a steam pro into your apartment to either repair or replace those valves so that they work. If they were working properly, given this is a two pipe system, You should be able to adjust those valves down to reduce the amount of steam entering the radiators. The traps should be inspected as well. Not knowing what pressures the system is running, and the fact there is reluctance to make any changes/adjustments to the heating system, I'm not sure TRV's will work. High pressures may be problematic to TRV's working properly.
The only problem with getting those valves repaired/replaced is the heating system needs to be off while that happens so you may have to wait for warmer weather to schedule someone in for that work.

MilanD

Btw, these valves come in 1" too. Your pic looks like it's a 3/4, but I can't tell for sure. It would be quite simple to replace what you have but the system would have to be turned off or someone might be severely burned.

bad_habit

Thank you all, for your feedback. I will of course hire an experienced pro to service all units however I wanted to get some feedback prior to this so I know what I am venturing into. Basically the simplest solution appears is to replace current manual valves with new, working ones so I can adjust as necessary. The more complicated solution would be to get TRVs with a remote actuator as MilanD suggested. Thank you all for the info!

Answerman

Yes you can install a TRV with a remote thermostat and a remote dial (the dial and sensor can be separate or combined). One common brand is Danfoss, the RA2000 model would be suitable. The picture below describes the one-pipe version, but the operator, dial, and sensor for the two-pipe version looks the same (and probably is the same, just the valve itself would be different).

You wouldn't replace the manual valve, you still want to have that for servicing and for adjusting the rate of steam flow, but install the TRV after it. By using an angle valve you may be able to fit in the TRV with minimal re-piping, but I'm not sure about that.

I know electronic TRVs exist for hydronic systems, but I'm not sure about steam- if they exist they're certainly uncommon. So no easy way to connect it to a NEST.

And yeah make sure your steam traps are working. If they haven't been replaced within the past few years, you may as well just have them replaced, it's easier than testing them and they're probably in bad shape anyway.

Answerman

MilanD said:

Trvs in steam generally refer to vents, and your system doesn't have a vent. Trap acts as a vent. That said, there may be thermostatic valves that can replace the current manual valve.

TRVs (thermostatic radiator valves) can be used for one-pipe or two-pipe systems. In one-pipe systems, the valve goes right before the air vent, and in two-pipe systems, the valve goes at the supply before the radiator.

TRVs actually work more reliably in two-pipe systems, since they're not really affected by system pressure: In a one-pipe system, the pressure needs to be pretty low for TRVs to work well, otherwise the pressure can compress the air inside the radiator, and force steam in even with the TRV closed.

I think it's best practice to install the TRV after the manual valve, rather than replace it, so it can still be used to shut off the radiator for maintenance (i.e. trap replacement) or to adjust the steam flow. The TRV is either open or closed, not in between, and I think you'd have to remove the operator to manually close it.

EBEBRATT-Ed

As @Abracadabra mentioned block the air flow in and out of the convector this will probably solve your problem

jumper

Answerman said:

MilanD said:

TRVs actually work more reliably in two-pipe systems,

I hear that thermostatic valves for two pipe steam work better than those for heatinghotwater. As long as traps function.

MilanD

@Answerman

I suppose in "trv", "v" can stand for both "vent" and "valve". Ones I installed on 1 pipe rads went into the 1/8" air VENT port and close the air elimination. On 1 pipe rad you cannot, or rather, should not install a tr VALVE, on the supply side. These rt valves usually have inside oppenings significantly smaller than the manual valves and therefore can waterlog the radiator or cause water hammer on 1 pipe systems, esp ones with cranked up pressures.

In 2 pipe, you have to do valve as there is no radiator vent, and the valve oppening size does not matter as it only supplies the steam. We then have the issue with broken, or rather, failed in open position traps and overall system health with traps on other rads in the system as a whole, but for this op, this doesn't really matter. Looks like someone recently serviced these at the op's unit as they have some blue Teflon tape hanging out. What has happened in other units and how well is the system maintained is anyone's guess (and op here posted it's not easy to get anything done in the building of 400 units. Holy cow - 400 units all individually owned but all on one system. Reminds me a little of post USSR Russia... Anyhow...)

I also suppose you can pipe the tr valve in a series with a regular manual valve, but in that case you can use any ol' 90 degree ball valve, or gate valve for that matter, to be able to manually control steam volume or shut it down completely. These trvs do come with a threaded cap you can use to regulate the opening, if one doesn't purchase the actuator unit (and that's why they are sold separately). So tr valve without an actuator can be used also as an expensive version of a regular manual valve.

As to @bad_habit issue - cover a part of the convector with some rigid insulation Styrofoam and be done for virtually no cost. Or, heck, crack open the window and pretend it's the 1920s, (minus the Spanish Flu).

Cheers, Happy New Year and enjoy your tropical apt! Wish I was there...

Answerman

MilanD said:

I suppose in "trv", "v" can stand for both "vent" and "valve".

No it stands for valve. In a one-pipe system the Thermostatic Radiator VALVE goes between the radiator and the air vent. Danfoss has a standard air vent you can use or use any vent you want.

MilanD

> @Answerman said:
> I suppose in "trv", "v" can stand for both "vent" and "valve".
>
> No it stands for valve. In a one-pipe system the Thermostatic Radiator VALVE goes between the radiator and the air vent. Danfoss has a standard air vent you can use or use any vent you want.

Got it. I call these vents, as they go on the vent side, although technically they are valve plus a vent. On hot water, I call them valves. I see now what you are saying. Thanks for clarification!