Harman P68 cycles fan on and off every two seconds

[dantm]

For the first time my Harman P68 went into a mode where the blower fan would cycle on and off for 2 seconds at a time, and this would happen no matter what the input to the buttons was...

It originally started when the room temperature reached the thermostat set value and it would normally go from high fan to low fan but it went into this cycle...this lasted about 15 minutes, and was repeating even if the unit was unplugged it would come back to this state.

Eventually it redressed itself and went back to normal.

Any thoughts on what it could be?

 

[Whitenuckler]

For the first time my Harman P68 went into a mode where the blower fan would cycle on and off for 2 seconds at a time, and this would happen no matter what the input to the buttons was...

It originally started when the room temperature reached the thermostat set value and it would normally go from high fan to low fan but it went into this cycle...this lasted about 15 minutes, and was repeating even if the unit was unplugged it would come back to this state.

Eventually it redressed itself and went back to normal.

Any thoughts on what it could be?

Was it related at all to the auger run times? I am thinking dirty ESP probe? Have you had the stove plugged into good surge suppression?

 

[dantm]

Not sure how to know if it was the auger run times? The distribution feeder wasn't running, it was like when it goes from high blower fan setting to low setting but then it would sound almost like it was cycling on and off. The effect was that the blower fan would go from off to low and back to off every few seconds (say 2 seconds on, then 2 seconds off, and repeat).

 

[Whitenuckler]

Not sure how to know if it was the auger run times? The distribution feeder wasn't running, it was like when it goes from high blower fan setting to low setting but then it would sound almost like it was cycling on and off. The effect was that the blower fan would go from off to low and back to off every few seconds (say 2 seconds on, then 2 seconds off, and repeat).

If it was happening that fast it could still be the ESP probe if you are in room mode. The auger works on a one minute cycle and takes time to change from the last duty cycle. Try stove mode and see if it works good. Just in case you have a bad or loose room sensor.

 

[dantm]

Yes I was in the room mode...the system eventually got out of that cycling state and the room mode continued to work fine. Will try your suggestion of the stove mode next time this happens.

 

[bogieb]

That sounds like how my stoves work on a UPS that is non-sine wave when on battery (by design, it will gracefully shut down while pulsing the blower). In that mode the exhaust fan will pulse and I think the distribution fan shuts off.

It is possible the grid had issues on 1 phase and the stove was detecting it as the shut down signal. If that phase was not completely down, just flickering, I could see that it might go between running mode and shut down mode, which would be confusing.

 

[zrock]

Sounds like what happened to my Breckwell a few years back after one of the motors seized up. During its start up cycle the blower would go low to high until startup cycle was complete and then it would level out. Turned out when the motor seized it took out my control board. New board and all is good now.

 

[Whitenuckler]

Sounds like what happened to my Breckwell a few years back after one of the motors seized up. During its start up cycle the blower would go low to high until startup cycle was complete and then it would level out. Turned out when the motor seized it took out my control board. New board and all is good now.

That was something I was wondering too. If there were some other problem with the stove besides the distribution blower, the control board might not like it and start to play games with everything else. Now that it went away it's pretty hard to figure it out. Maybe it will never happen again, plus you need to be there to hear it happen. Mines in the basement so I'm only down there a few times during the daytime hours. I could test the room thermostat being the cause though if I go down and play with the connection on the back of the stove.

 

[zrock]

As i was sitting here reading this again i remembered when i first got the stove i had a Cyber Power pure shine UPS on the stove and randomly i would hear one of the fans kick on for 2 seconds and then gone.. Could never figure it out over a couple of years until one day i decided i would hook up a tower fan to the UPS and give it a run and recharge. Well my fan did not survive for 10 seconds before it went up in smoke. Took the UPS and got rid of it and never replaced and the fan startup disappeared with it as well.. Not sure if you have any sort of battery backup on it but maby remove it if you do and give it a try