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DanDaMan 03-01-2013 10:14 PM

Need help on how to test the numerous thermostats in house
 
We recently bought a ~25 year old house, which is rather odd in its heat system.

It has 3 levels above ground plus a crawl space. Crawl space has a gas furnace which heats the main ground level, and then the 2nd and 3rd level are heated from a hot water heating boiler connected to hot water vents throughout the 2nd and 3rd floors. In the room with the water boiler, there are numerous (~12) what seems electronic relays from the pipes leaving the boiler.

In the 2nd and 3rd floors, I have ~ 8 different thermostats in various rooms. I assume each is connected to those relays so I can control the heat in individual rooms. But I find that in some rooms the heat vents along the wall are not warm yet the thermo in that room was turned up almost all the way. Then in other rooms the vents are warm but the thermo is not very high (almost off).

I want to know how I can test if each thermo is working (has power and connected to the water boiler), and how to know which heating vents each thermo actually controls.

Anyone have any tricks to test. I do have a multimeter, so I assume it should be easy with some instructions.

Oh, when I remove the existing thermo to test, do I need to kill power to them? I assume power is low voltage to these, so I doubt it. If I should kill power, how would I do that? Do I need to turn the pilot light off at the water boiler?

Lastly, I bought some digital thermos to replace the ancient manual dial ones. I assume there is no difference connecting these to a hot water heating system vs a typical gas furnace.

Thanks

TarheelTerp 03-01-2013 10:35 PM

Quote:

Originally Posted by DanDaMan (Post 1127861)
It has 3 levels above ground plus a crawl space.
Crawl space has a gas furnace which heats the main ground level,

the 2nd and 3rd level are heated from a hot water heating boiler connected to hot water vents throughout the 2nd and 3rd floors.

In the room with the water boiler, there are numerous (~12) what seems electronic relays from the pipes leaving the boiler.

In the 2nd and 3rd floors, I have ~ 8 different thermostats in various rooms. I assume each is connected to those relays so I can control the heat in individual rooms.

Wow! do you ever have your hands full!

Quote:

Lastly, I bought some digital thermos to replace the ancient manual dial ones. I assume...
Lastly first... do NOT add to or change anything. ANYTHING.
Don't assume you'll need to or that ANYTHING you might add will be better in any way than what you currently have... even after a) you know what you have and b) you REALLY know what you have.

Quote:

I want to know how I can test if each thermo is working...
I do have a multimeter, so I assume it should be easy with some instructions.
Oh, when I remove the existing thermo to test, do I need to kill power to them?
I assume power is low voltage to these, so I doubt it.
If I should kill power, how would I do that?
Do I need to turn the pilot light off at the water boiler?
Start by creating a paper and ink wiring diagram and operational schematic of what wiring and piping and controls are existing and presumably is/was working.

You should already have this somewhere...
Don't be shy about getting a pro in to do this for you if you don't.

Really. If you don't have a schematic (wiring diagram) to work off
this MUST be done first. Getting the controls right is an art.

Then... once you have something to check... you can check it.
Most of that will be about continuity (without power).

And most of that checking can probably be done by the controls guy you hired as he goes along to create the operational schematic and wiring diagram.

hth

beenthere 03-02-2013 06:08 AM

Might have an actuator or a couple of them that are bad/worn out. The thermostats may not directly wire to the boiler. They may wire to a zone control panel, which controls the valves and the boiler. Need to trace where the wires go to/come from that are connected to the actuators.

danpik 03-02-2013 07:52 AM

The "relays" you spoke of are zone valves. Each zone valve is controlled by a thermostat. When the stat calls for heat the zone valve is supposed to open and allow hot water to circulate. The opening of the zone valve also triggers the boiler pump to start and the burners to fire if needed. These zone valves, as Beenthere has mentioned, do go bad and stop working. They also have, on most models, a bypass setting to manually keep the zone opened. I would suggest finding the model of the zone valve you have, research how they are wired, and then troubleshoot to see if they are working.

av-geek 03-02-2013 09:48 PM

To check which zone valves are working, it's not a hard process, but you will most likely need 2 people to test, and a pair of 2-way radios, or cell phones to use to communicate back and forth. Have a partner in a room at the thermostat. Place either a test light or a multimeter on the connection to a zone valve. You may need to unplug the zone valve in question first and stick the meter probes in the plug to it. Have your partner then switch the thermostat on and of, and you should see action on your meter or test light corresponding to the operation of the thermostat. If nothing, go to the next zone valve and check it in the same way. Once you find which zone valve goes to which room, label the wires with a sticker or tag.

If you find some valves are "unidentified" or that you are not getting any voltage readings with the thermostats are switched on and off, you may have a problem with a thermostat, but this is unlikely.

If all the zone valves are identified, switch them each on one at a time. You should be able to feel if the zone valve actually activated or not by feeling the water pipe before and after the zone valves. When the valve is activated, the pipe leading out of it should get hot. If it's not, you may have a bad zone valve.

Once you have determined that the hot water is flowing through the zone valve, go to the room you activated the thermostat in and see if it's got heat going to it. If it isn't, go to other rooms and see if they are getting heat. Once you have determined the room that's getting heat, use a sharpie or a sticky label and write on the PIPE which room that received the heat. Do this for all the other rooms. Now, all that you gotta do is re-arrange the labeled plugs on the zone valves to match the labels on the pipes!


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