Hello:

I have a 2-zone (upstairs & basement) hot water baseboard system (oil-fired boiler) and I am having trouble with the basement zone.

It seems as though the zone valve for the basement is stuck in the on position. The basement thermostat does not seem to control the valve anymore (just started this week); the heat is always on high in the basement, even when the thermostat is turned off. The upstairs zone if functioning fine, thermostat controls the temperature.

I don’t know if I have a problem with the thermostat downstairs or the zone valve (or perhaps something else?). If anyone can offer some advice on troubleshooting this problem it would be greatly appreciated.

 

It sounds like your zone valves, but I'm not familiar enough with them to advise you further. Someone should be offering advice soon.

 

An easy way to test is to disconnect one of the thermostat wires going to the zone valve. If the valve stays open, the problem is with the zone valve.
Honeywell zone valves are particularly notorious for sticking either open or closed. This is due, 99% of the time. to a bad motor. The motor is far less expensive than a whole powerhead or zone valve. Replacing one takes me about 5 minutes. Shouldn't take you more than 15 minutes.

 

What type of zone valve and thermostat do you have? Does the basement zone run only when the other zone runs, or all the time? Try turning both thermostats all the way down, then see if the circulator is running. If you have honeywell zone valves, they seldom get stuck in the open position, but Automags, if not powered, will stay open. If you have automags, check to see if you have power going to them, or put a screwdriver at the post end. If it is powered closed, the screw driver will be pulled towards it by the electromagnet in the coil. Could also be a thermostat that failed closed. Do you have a multimeter & know how to use it?

 

I have eerie zone valves. I tried turning off both thermostats, the furnace continued to run, but only the basement zone was heated. I removed the motor from the valve, it closed (I was able to turn on/off the heat in the basement with the latch underneath the box). I am going to pick up a new motor today to replace the one I removed, hopefully that will solve the problem. Thanks to everyone for the feedback.

 

The lever under the valve should only open it not close it. If it was latched open and you unlatched it, there may not be a problem at all. If someone latched it open, it would stay that way until a call for heat or unlatched. The motors are the same between Honeywell and Erie. Hope you got it solved.

Ken

 

Hi ; problem seems to be solved.

I purchased a new motor (honeywell motor; as noted above it looks identical to the eerie one I removed).

When I opened the latch manually, I was getting heat in the basement only when the upstairs thermo called for heat; everything functions as it did before with the new motor on.

Thanks to everyone for lending your expertise, it is greatly appreciated.