Harman pellet stove room temperature setting not working

[matt061577]

I have a Harman P68 stove. Mostly works fine except it won’t maintain a 68 degree room temperature. If I set the dial just above 70 it will heat the room up to around 77 but if I turn the knob just below 70, the stove will shut down and then just allow the temperature to drop completely. I turned the oil furnace thermostat down to 63 and the room will go to 63 while the pellet stove does nothing. It will start immediately if I try to heat the room to the high 70s but below that just shuts down. The stove is at least 15 years old.

 

[jackman]

Welcome to the forum. That sounds like the dreaded Harman potentiometer (aka pot) problem. Dead spots on the potentiometer cause an intermittent connection. It's the same as the scratchy noises on the volume control of an old fashioned radio. There's several threads on this forum about it. You can try compressed air and/or DeOxit contact cleaner, and quickly working the knob back and forth to see if that fixes it. After that you'll need to replace the pot (easy if you're handy with a soldering iron) or the board. Many years ago I was able to purchase replacement pots on eBay.

The other possibility is a flakey room temp probe. You may want to try running in Stove mode to see if it makes a difference. Please put the model and year of your Harman stove in your signature.

 

[bogieb]

I second what @jackman said. I had my POT dial develop a dead spot on my P61a. I ended up installing a thermometer to control it from a different area of my basement. I had already been thinking about doing that, so the issue just forced me to get my butt in gear.

 

[Whitenuckler]

I have a Harman P68 stove. Mostly works fine except it won’t maintain a 68 degree room temperature. If I set the dial just above 70 it will heat the room up to around 77 but if I turn the knob just below 70, the stove will shut down and then just allow the temperature to drop completely. I turned the oil furnace thermostat down to 63 and the room will go to 63 while the pellet stove does nothing. It will start immediately if I try to heat the room to the high 70s but below that just shuts down. The stove is at least 15 years old.

If you are in Room Temp Mode, and if you have a newer control card with the igniter switch, then if you switch the igniter switch to down (off) (manual) then the stove should not shut down, just idle. The room temp probe should be relocated to the middle of the room half way down the wall (BEST), or moved in back of the stove near the bottom where the distribution blower is. Check you connections for the probe on the back of the stove.

 

[mtnbiker727]

Where is your temperature probe? I just have mine coiled up behind the stove. I pick a temperature on the stove that gives me the actual room temperature I want.

If the temperature probe is on a cold wall behind the stove, that will make the stove act strange... if the stove warms the wall, the stove won't run, but if the wall is cold the stove will get the room a lot hotter than your set temperature.