Thermostat Emergency!

[Chris112]

I recently bought a condo that has a thermostat in the middle of the living room wall. Its a dial that has numbers 1-5 on it (not degrees). Well I unscrewed it from the wall to try and find out if I can change it and it actually fell off and broke. It was someting I never saw before! It was one solid (looks hollow) hard wire and that was it! IT looks like it goes down the wall to a valve on the end of the heating unit. Thats all there is. It broke on the edge of the thermostat and I do not see a way of putting it back in. If any of this sounds familiar to someone I would greatly appreciate it! Please let me know if where I can find a replacement! There is no namebrand on the valve or the dial. I brought it to a local plumbing shop and they were clueless.

Thanks and I hope you can help!

[geniere]

...It was one solid (looks hollow) hard wire and that was it! IT looks like it goes down the wall to a valve on the end of the heating unit. Please let me know if where I can find a replacement...

I think you have a pneumatic thermostat (works by air pressure) and the "valve on heating unit" may have manufacture info. Other than that I can't help except to say if it were me, I'd replace it and the valve with a modern electric control.

[LazyPup]

I agree with Geniere,, from your description it sounds like you have pneumatic controls.

Pneumatic controls are normally only used on large commercial heating and cooling systems such as those in schools, hospitals or large high rise buildings. You stated that this is a condo so I am guessing it is either a very large condo building or perhaps an older school building that has been converted to condo's. In either case there would be a central boiler room in that building and it should be attended by an operating engineer. Contact the operating engineer or building superintendant and they should have replacement t/stats in thier stock and you could most likely purchase an exact replacement from them and possibly solict assistance to install it.

[Chris112]

Thanks for the response. That information does sound like it makes sense to me. It is a common boiler room. They use to be appartments that were converted to condos.. The heat is included in the codo fees. Now is this system able to be upgrade in just my unit? I mean can I get an electrical setup on an older system like this?

And do I HAVE to replace the valve at the same time as the dial? or is there a way to just add a dial? Is there any websites you recommend I can shop on? and do I need a plumber?
Thanks

[LazyPup]

The only part you really need to change is the defective wall thermostat. There would be no real advantage to converting to an electric thermostat and control valve.

[Chris112]

The only part you really need to change is the defective wall thermostat. There would be no real advantage to converting to an electric thermostat and control valve.

Thank you.. That what I was hoping for. Now do you have any advice on how to change it. The break in the wire was clean. Do you know where I can get a replacment thermostat? How do I actually install the new thermostat? Is there anything that needs to be done to the system? (remove air etc..?) I am just very unfamilar with this setup.

Thanks again!

[LazyPup]

I would suggest you begin by discussing the problem with your building superintendant or operating engineer. They will know exactly what type of system you have.

If is is in fact a pneumatic control there is no wire. It will have an air line to the thermostat which may be very small diameter copper tubing or perhaps a plastic tubing.

Normally all that is required is to connect the tubing to the thermostat and hang the thermostat.

[Chris112]

I would suggest you begin by discussing the problem with your building superintendant or operating engineer. They will know exactly what type of system you have.

If is is in fact a pneumatic control there is no wire. It will have an air line to the thermostat which may be very small diameter copper tubing or perhaps a plastic tubing.

Normally all that is required is to connect the tubing to the thermostat and hang the thermostat.

I did talk to the superintendant and he was clueless. He just recommeneded me to a plumber that does work around the buildings. Again from what you say I believe it is a pnematic control. It isnt a wire in the sense of an electrical wire, it is more of a hollow tube. Very thin! Once the thermostat broke off, a little water or liquid came out when I turned the dial. On the back of the thermostat it doesnt look like the tube can be removed, its under a round disk on the back and I cant see how to remove the remainder of the tube.

What do you think now?

[Chris112]

Someone else I talked to said that "a pneumatic thermostate would have two tubes and would also need an air compressor."
Is that true? Because in that case I only have 1 tube.

[Chris112]

my setup looks VERY much like this

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=6045898131&fromMakeTrack=true

just a different knob..

Do I need all the parts in the picuter? does it come as one unit?

[LazyPup]

Very few plumbers ever really come in contact with pneumatic controls so that would not be a very good source of information. You would need the services of a "commercial HVAC tech" but rather than that, I would suggest you first take all the pieces of your old thermostate to a local commercial HVAC parts supply house and show them to the counter guys. They will probably be able to instantly identify it from sight and match you up with a suitable replacement, if not, they will at least know who in your community works on those systems and could help you.

Perhaps a little general explanation of how your heating system works will help you understand what your working on.

In large buildings such as yours it is far more cost efficient to have a central boiler that produces either low pressure live steam (under 15psi) or hot water that is circulated through pipes in the building. The main headers are kept hot at all times.

From the header pipe a branch pipe is run to your radiator and there is air diaphram control valve on the input side of your radiator that is held closed by an internal spring.

There is also an air supply pipe from the air compressor in the boiler room and they tap off of that and run a small diameter tube to a TEE connection on the control diaphram. A second small diameter tube is then run to your wall thermostat which is simply a tiny air valve controlled by a bi-metal thermostat strip. When the room temp is satisfied there is a tiny hole in the thermostat that allows the air to vent out. (You may have noticed a slight hissing sound coming from the thermostat at times.)

When the room air cools the Bi-metal strip contracts and closes off the vent port trapping the air in the thermostat. This then stops the air flow from the control to the thermostat and the air then enters the diaphram in the valve and lifts the diaphram, which in turn opens the valve allowing the steam or hot water to enter the radiator.

When the room air rises the bi-matal expands, again opening the air bleed port allowing the air pressure to escape from the diaphram and the spring on the opposite side of the diphram pushes the diaphram closed, which in turn closes the valve stopping the steam or hot water flow.

Here is a tip,,if your apt is cold now you should be able to take a spring clip such as used on potato chip bags or a large clothes pin and pinch the end of the air hose closed. Within a few minutes the supply valve on your radiator will open and allow the steam or hot water to enter. When the room is warm remove the clip. This will give you a manual control until you can obtain the parts.

[Chris112]

Ok I am slightly more confused now... I assumed there is only one wire/pipe/tube like showed in that picture on the link. It goes to the valve and the control. I dont see a 2nd tube going to the control that would i would be able to pinch off. Its a hard metal tubing that I would probably need to crimp off. Either way I only have 1 tube that I "assume" runs to the valve on the side of the heater?!? Am I wrong??? If it broke on the end near the control unit do i need to replace the entire thing including the valve? The hard wire on the valve runs up the wall and the control piece is directly above the valve. So I assume they connect. (Just like the picture).

[Chris112]

Here are some pictures of my problem.. The back of the thermostat, wire out of the wall, and the valve on the heater.. I hope this helps. These are actual pictures of what I have!