Steam Valve Radiator Thermostat - Any Good?

ElmerJay

Hello all,

I want to use a thermostat connected to the steam valve release that shuts off the valve when the temperature is reached, thereby turning the radiator off.

Rather than using a thermostatic steam valves that connect to the steam pipes coming into the radiator, like the one I looked up one on the web such as the Danfoss Non-Electric Actuator Zone Valve Dc1040.



So I have basically two questions:

1. Is setting each room by itself just a dumb consumer band-aid and the

real problem of the steam system should be fixed if the house can't be heated properly?

2. Is there a problem with using the release valve instead of the intake valve?



Thank you very much

ElmerJay

nicholas bonham-carter

thermostatic radiator controls

if your system is well maintained, these valves [trv's] can even out the hot spots in your system. they must not be installed on a radiator next to the thermostat. they will not do a good job of compensating for inadequate main [not rad] venting.

is your system 1-pipe or 2-pipe, as the valves used vary depending on application.

if your system was installed/sized correctly in the beginning, simple corrections may restore it to more even operation, however, if changes to the structure/room layout have been made, then trv's may be a help where an over-sized radiator now exists in a now-smaller room.--nbc

Rod

TRVs

Hi- You didn’t mention whether you have a one pipe or a two pipe steam system.  The type of system is determined by the number of pipes connected to each radiator (ie 1 pipe = a 1 pipe system,  2 pipes = a 2 pipe system)   TRVs (Thermostatic Radiator Valves) can be very useful.  I use TRVs on about half of the radiators in my home. They are really handy in the bedrooms and also allow me to shut the heat off in unused rooms to save fuel. (The minimum setting is 42 degrees so this makes sure the room doesn’t freeze)

If you system has some issues you probably want to get those resolved first before using TRVs. If you are having problems let us know what they are and maybe we can advise you as to how to deal with them.  If you don’t have them already, you might want to take a look in the SHOP area on this website as there are some great books on steam heating which will be a big help to you. They have saved me thousands of dollars by enabling me to make my steam system run more efficiently and economically.  I’d start with “We Got Steam Heat!”-

http://www.heatinghelp.com/products/Books/5/61/We-Got-Steam-Heat-A-Homeowners-Guide-to-Peaceful-Coexistence

Below is a little “burb” on TRVs and I have attached a Danfoss sheet on the 1 pipe model TRV which might be of help to you.

- Rod



TRVs

TRVs stand for Thermostatic Radiator Valves.  They are used on hot water and steam systems to regulate the heat output of the radiator.  



2 Pipe TRV -On a two pipe steam system, the TRV is installed on the inlet pipe and shuts of the incoming steam when the temperature reaches the adjusted setting on the TRV.



1 Pipe TRV - On a one pipe steam system the TRV works on a different principle. The TRV is installed between  the radiator and the steam vent.  A one pipe steam TRV also needs a vacuum breaker to allow air back into the radiator when the boiler shuts off.  (Note - On the TRVs mentioned below , the Macon TRV, the vacuum breaker is external and on the Danfoss TRV, it is internal (built in).

It is important to get the proper model TRV to match the type (1 pipe or 2 pipe) of system you have.  



How a 1 Pipe TRV Operates - As mentioned above, the one pipe TRV is mounted on the radiator vent hole, ,between the radiator and the radiator vent.  When steam enters the radiator, if the room temperature is below the setting on the TRV, the escaping air goes thru the TRV and out the air vent, when steam reached the air vent it closes just as it would without the TRV. When the boiler shuts off, the vacuum breaker allows air to re enter the radiator.  This cycle continues until the room temperature reaches the setting on the TRV. The TRV valve now closes and prevents air from escaping out the vent. With the air trapped in the radiator, steam is now prevented from entering  until the TRV drops below the set temperature and reopens, allowing air to escape and steam to now fill the radiator again.





Here's some links to several different models.

 Macon - The Macon model for one pipe steam -   http://www.maconcontrol.com/opsk1204.html



Danfoss TRVs: http://na.heating.danfoss.com/Content/c3841968-5947-489a-a1f1-702664881446_MNU17392439_SIT209.html



Danfoss Animation

Note: These animations show TRVs for hot water systems however the mechanism is basically the same on the one pipe steam model. - Click on the following link:

http://na.heating.danfoss.com/Content/161a8b0f-a195-42b2-9487-7ee4083398cf_MNU17483715_SIT209.html

This will take you to a Danfoss page which will say “The page can not be found” Go to the menu at the top of this page and click on “Knowledge Center”. On the Knowledge Center page, click on “Operation of the RA 2000- Thermostatic Operator ‘and that will take you to the animation page.  For some reason the direct link isn’t working at the moment.

 

You can install 1 pipe TRVs yourself.  You should be able to get these units from your local heating supply or on the internet. (Try Pex Supply - http://www.pexsupply.com/ Type in the word  “Danfoss”in the Search/Find window and that should get you to them.



Note: The Macon TRV comes with a radiator vent included. On the Danfoss your must supply the vent. It needs to be a straight vent rather than the normal angled radiator vent.  You can use a 1/8 inch 90 degree street elbow between the TRV and then use a regular angled vent,

       

moneypitfeeder

what's the real problem?

If the real problem is that you have oversized rads (due to new insulation, windows, etc) and if you have a 2 pipe system, I would be looking into orifice plates for the inlet side of the problem rads. They don't need electricity, don't need new packings, or guts, they are simply a hole in a plate that allows a certain regulated amount of steam to enter the rad. It won't work if you have a one pipe sys. (please anyone correct me if I'm wrong) because while its limiting the steam entering, it doesn't allow for a large enough path for condensate to leave. But if your trying to create "zones" that you can constantly change to suit your needs all this is irrelevant.

moneypitfeeder

what's the real problem?

If the real problem is that you have oversized rads (due to new insulation, windows, etc) and if you have a 2 pipe system, I would be looking into orifice plates for the inlet side of the problem rads. They don't need electricity, don't need new packings, or guts, they are simply a hole in a plate that allows a certain regulated amount of steam to enter the rad. It won't work if you have a one pipe sys. (please anyone correct me if I'm wrong) because while its limiting the steam entering, it doesn't allow for a large enough path for condensate to leave. But if your trying to create "zones" that you can constantly change to suit your needs all this is irrelevant.