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-   -   Peerless oil furnace - keeps turning on when temp exceeds target temp (

eugenet1979 12-22-2011 08:30 PM

Peerless oil furnace - keeps turning on when temp exceeds target temp
I have a fairly new Peerless oil furnace. The heating system is hydronic, running hot water through convectors in the house. An indirect water heater is connected to the boiler, regulated but its own aquastat.

Here are all the known conditions:

1. Room thermostat set at 67F target temp, current room temp 73
2. When burner is turned on by the room thermostat, the switch is triggered by an electromagnet and the furnace stays on as long as temp is below target temp.
3. The burner keeps turning on about every 1/2 hour to 40 mins for 2-3 minutes at a time.
4. Internal water temperature set to be between 160 and 180 degrees, with two dials setting min and max temperature
5. Turning the Min dial to above the current water temp will trigger the boiler to kick in and circulate hot water through the house for a few minutes until water temp reaches 160, keeping each convector warm.
6. This is plainly wrong since if it was summer and room temp exceeded target temp, i wouldn't want the radiator to be warm.
7. It's not the water heater triggering the boiler. I can hear the relay click when I turn that aquastat above its current temperature, plus that should only trigger the water hear, not house heating.

I'd think the room thermostat is the main governor so if room temp is above target temp, the water in the boiler would cool down to room temp until boiler triggered by that room thermostat.

Any ideas what to look for?


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