Harman P68 Blower Issue

[mr.heat]

Hi,

I have a Harman P68 that is about 5 years old. At low speeds the distribution blower "surges" from a moderate speed to low blowing speed. The dis blower light also dims when this is happening. Any idea whats wrong? No flashing fault lights. Could this be a sign that the blower motor is going to fail ? Would a dirty esp cause this concern? At all other speeds the unit works great and blower sound very strong.

Thanks.

 

[DexterDay]

Could be a sign of eminent failure.. Could just be a "Spot" in the setting where the voltage is a little inconsistent.

Not sure it would be ESP related. Hopefully a Harman owner will be along shortly to help you. Wish I could.

Have you serviced the unit regularly? Taking the combustion and convection blowers off and cleaning and possibly lubing them yearly

 

[mr.heat]

Yes I have cleaned the stove as rec. by the harman manual. I have cleaned the blower. I just cleaned the esp probe today and we will see if it changes. It runs great when blowing on high speed, but when the room drops below temp and the blower turns back on at the slower setting, thats when it is most aparent. I have a spare blower on hand...just do not want to change it yet...Any other feedback woul be much appreciated. Thanks for the response!

 

[Lousyweather]

the light dims as well? ALL of the lights, or just the dist blower light? Unlikely its the ESP probe, more likely the circuit board......Usually the bad ESP's are either bad or good......not in-between. What about your power supply? The distribution fan is the highest demand fan on high inthe unit, so, if your stove were starving for power, it might be evident in the distribution fan first. Unfortunately, your unit is no longer under warrantee. Have you tried running the blower itself connected directly to line voltage to see if its the blower at all? If you connect it directly and it doesnt do this, you will have eliminated the blower as the issue. Next is the circuitboard........a bad spot on the rheostat? Not unknown.

 

[kinsmanstoves]

Running in room temp mode the control board has somecontrol over the distribution fan and will speed it up or drop it down. The light is an indication of how much power is going to the blower. dim light means lower power.

Eric

 

[Richgvt]

The blower on my p68 used to cycle on and off and was being irregular. Just did not seem right. This was after a power surge. The power kept turning on and off rapidly. I finally got the dealer to install a new circuit board which fixed it. I need to get a better surge protector to prevent this. Anyone know how long ignitors last? Mine is about 5 years old and thought it might be a good idea to have a spare on hand.

 

[yogi9644]

My stove is having this same issue. I see I'm not the first, however, I haven't heard from anyone what actually fixed this problem. I've replaced my distribution blower and that fixed the problem of the blower sometimes not working when starting up in room temp mode, but the fan speed (and light indicator) still fluctuates on startup in room temp mode. I may start using room temp mode on the manual setting, but I'd still like to know the cause of the problem rather than just bypassing it.

Here's my post from the other thread:
My Harman P68 has this same problem. It happens mostly at night when I turn the stove to Room Temp mode from Stove Temp mode. It typically shuts off for a few hours, then it reignites in Room Temp mode. After it ignites, the fan was doing the same thing, alternating from low to medium speed like the revving of an engine almost. If I turn the power off and on and switch it back and forth from Stove Temp mode to Room Temp mode and I can eventually get it to stay consistently on high fan speed. Like your issue, my combustion blower light was fluctuating just as the fan speed was. After a few weeks of this, the stove would turn itself on in the night on Room Temp mode and sometimes the distribution blower wouldn’t even turn on at all. I called a tech out, and since it seems to only happen from a cold start in Room Temp mode I wasn’t able to replicate the problem. They replaced the distribution fan and now it still fluctuates when it starts up in Room Temp mode, but it hasn’t done what it did before where sometimes the distribution fan wouldn’t work at all. That leads me to believe that perhaps it was partly the blower and also the circuit board? When the distribution fan was replaced, they put some sort of gasket fabric material in between the fan and a metal sheet to prevent noise, but it pushed the distribution fan out of place just enough that there was a metal on metal noise on medium speed, so I took out the gasket fabric and the noise mostly went away, although I think the fan is louder than the original one was…any suggestions or ideas?
thanks

 

[yogi9644]

Just to follow up. I took out the circuit board and tightened all connections, and I removed the ESP sensor and cleaned it off with window cleaner. It was pretty well covered in soot and carbon and I had never cleaned it before over the life of the stove (3 years). It now runs very well and the distribution fan blower and light are all consistent.

 

[yogi9644]

Just to follow up. The problem with the distribution blower kept coming back. I would clean the stove, clean the ESP sensor and it would work fine again for a while, but it would always come back. The biggest problem was when I would turn the stove from Stove Temp to Room Temp at bedtime. This is when the distribution blower would act up the most. The stove would shut down because I'd set the Room Temp to lower than it had been. When it would turn on a while later sometimes the distribution blower wouldn't even turn on! Because of that, I tried to use stove temp mode as much as possible and avoid room temp mode.
Lately when the stove was making a squealing noise when the auger motor would turn I took the back of the stove apart, convinced it was coming from the auger motor. While back there, the distribution blower started it's speed fluctuation thing and I grabbed the ESP probe plug and pushed it hard into the board and the problem stopped! I bought a new ESP probe and the problem finally seems to be solved. I haven't heard of this happening to anyone else, but I don't think the old ESP probe even locked into the board with a clip plug like the new one does. Anyway, of you get a fluctuating distribution blower with the light fluctuating as well, you might want to check how it's connected to the board.
Oh, and the squealing noise? I took the dealer's advice and turned the stove up to its highest setting until the noise stopped, usually after no more than five minutes. The new burn pots that have no holes near the bottom also make a world of difference with noise from the auger scraping the hard carbon deposits at the base of the burn pot. I'm just glad I didn't destroy the auger motor when I slathered it with anti seizing automotive lubricant.