View Full Version : No heat upstairs

10-10-2005, 12:04 AM
I have hot water baseboard heating and for some reason the upstairs thermostat seems to be opening the zone valve but not turning on the circulating pump. The downstaris zones appear to work fine and when they engage the circulating pump, I get heat upstairs.

What is supposed to turn on the circulating pump? Does the thermostat have two output control lines or is there some other relay that turns it on? A schematic or wiring diagram would be nice.

10-10-2005, 06:19 AM
WE are the ones who would need a schematic of your control system. If you have the wrong controllers, or they are wired wrong that could happen. It could also be a failing control or a broken, or loose, wire.

10-10-2005, 09:58 AM
You should have Taco control valves or similar.
If you have common circulator pump and control valve for each zone
then zone thermostats are turning ON and OFF correspondent zone valve
and valve’s contacts are turning ON and OFF circulator pump.
Assuming your system was working before, you should check failing
valve itself (contacts) or wiring around this valve.

- Vitaliy (not a profession plumber)

10-11-2005, 11:56 AM
If you have a zone valve that is opening check if there is an end switch ( a set of contacts that close when the zone valve is wide open ) There will be 2 wires off this end switch back to the pump control. Some systems are set up this way.

10-11-2005, 12:43 PM
Is there a manual off/on lever that you could open when the pump is running?
What name is on the zone valve?

10-11-2005, 01:43 PM
I get heat upstairs whenever the upstairs zone valve is closed and the circulation pump is running. The upstairs thermostat is properly opening the valve but I guess the end switch in the upstairs zone valve is not working. The circulation pump turns on when any of the other zone valves are opened. So... as a work-around I just leave the heat on downstairs set to a higher temp than the upstairs and that helps.

The zone valves are Honeywell 9101's

P.S. I would have normally already tested the end switches with my meter by now but someone ran into our van saturday and I have a broker collar bone. That has slowed me down a bit.

10-29-2005, 02:06 PM
Well my shoulder has gotten good enough (sort of) to go and use my meter. I measured 24VAC across the end switch then tripped it manually - no change. The microswitch is definitely toast.

Can just the end switch be replaced or do I have to replace the entire valve assembly? If so, where can I buy one?

OK, now I got to go rest my shouler. It's starting to cramp up.