Harman Pf100 not shutting down

[d-dayman]

On warmer days into the 40’s etc. the furnace SOMETIMES won’t shutdown. I keep my thermostat at 71, but the furnace will keep running and heat the house up to 79 or more.

I cleaned the esp and still it won’t shut down. I even tried turning it to OFF and it continues to run hours later.

Any ideas on the issue.

 

[salecker]

Too much wood in the firebox

 

[d-dayman]

Sorry. It’s a pellet furnace. Guess I should have stated that.

 

[Mr._Graybeard]

Thermostat? That's the first place I'd look

 

[brenndatomu]

Yup, unhook one Tstat wire, if it shuts off then I'd say Tstat is sticking on