Zone receiving heat even though thermostat is not calling for it

Dan_14

Our home has three heating zones. We recently had a plumber install an indirect water heater and we have noticed since then that the baseboards on the lower level are warm and that the thermostat shows a temperature reading of 72F even though we set that zone to call only when the temp drops below 60.

We called the service co with whom we have a contract and they said that the plumber who installed the water heater did not put in a zone valve for it. I'm guessing that was a big No-No. He also found that the flow valve for that zone was stuck in the open position and so he changed the motor. However after he left we still found heat going to that zone. He did mention something about gravity feed.

I'm at my wits end about how to stop this zone from calling for heat as the heat rises and the temp reading on my thermostat upstairs goes up to around 70 and the bedrooms stay cold unless I raise the thermostat upstairs to 71 or 72.

HELP!!

Dale

Pump?

I think you need a flow control valve on the supply and return side of the zone you find is overheating. The boiler is running more now to keep the domestic hot water hot. Also sounds like this indirect uses a zone valve and the boiler pump to circulate water to it. The indirect should have check valves allowing flow in only one direction and some sort of isolation so the heating zones can't be powered when the indirect is calling. Make sure the offending zone valve is not powered when the indirect is powered. If the indirect has it's own pump is that pump and the boiler pump in series? pumps in series can force flow past zone valves.

hydronicsmike

Can you...

...provide a mechanical sketch of your system??