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??

 

[rickwai]

Have you done a complete cleaning including the exhaust from the stove clear out to the termination cap? Also have you pulled the combustion fan and cleaned the vertical flues where the chain hang down? If the exhaust path is restricted it can cause this issue because it cant get the heat away quick enough to shut down

 

[d-dayman]

Have you done a complete cleaning including the exhaust from the stove clear out to the termination cap? Also have you pulled the combustion fan and cleaned the vertical flues where the chain hang down? If the exhaust path is restricted it can cause this issue because it cant get the heat away quick enough to shut down

I have, but maybe I need to do a better job of it. I’ll try it again to see what happens. How often should that be done?

 

[Mt Bob]

1- control board
2- pile of ash sitting in front of exhaust probe
3-dirty stove/furnace

 

[rickwai]

I have, but maybe I need to do a better job of it. I’ll try it again to see what happens. How often should that be done?

Depends on how much it is used and how long of a horizontal run on the exhaust you have. Long horizontal runs catch and build alot of fly ash. Most Pf100 furnace installs I have seen have long horizontal runs and elbows. I would brush the pipe out and completely clean the stove then do the "leafblower trick" with the combustion fan out then put fan back in and leave the burn chamber door open and do it again. Youtube "leafblower trick" if you dont know what it is.
Also, Does your chain shakers still work? When turning the handle do you hear the chains shaking freely?