Weak blower on harman xxv

[Iamjoefox]

So I have owned this stove for 5 years but it’s a 2010 model.
the blower motor is much weaker this year than before. I. keep the stove pretty clean cleaning The combustion and blower motors. I have tried cleaning the boards knobs with contact cleaner with no help
Do you think the blower motor needs to be replaced or the control board? Or both?

 

[Mt Bob]

Yes.

 

[jackman]

How does it respond when you run self test?

 

[Iamjoefox]

Everything works as it should in test mode, just weak distribution fan.

 

[jzm2cc]

Try cleaning and lubing the fans bushings on the both ends of the convection fan. If you carefully remove the rubber end caps they can be accessed. Use a drop or two of 3 in 1 small motor oil.

 

[rickwai]

I cant remember... There is not a hi/lo switch in the alcove behind the circuit board

 

[Washed-Up]

Everything works as it should in test mode, just weak distribution fan.

Take a good look at the fins on the distribution fan, post a pic or 3, if they’re caked with dust or other junk use a Roth brush and clean them off and vacuum them. As stated above, if the combustion motor is the culprit, then lube the bushings top and bottom.
It sounds like your board is fine if it’s all working in test mode.

 

[Iamjoefox]

I’ll take some pics when I get home. The distribution fan def has a little build up on it I was worried about being too aggressive cleaning it.
I was worried about the knob on the mother board having a dead spot at full speed.

 

[SidecarFlip]

Try cleaning and lubing the fans bushings on the both ends of the convection fan. If you carefully remove the rubber end caps they can be accessed. Use a drop or two of 3 in 1 small motor oil.

BINGO. Should be oiled yearly as well as the bearings in the combustion fan. Only time an electric motor gets weak is before it goes up in smoke. Most times it will be the bearings.

 

[SidecarFlip]

I’ll take some pics when I get home. The distribution fan def has a little build up on it I was worried about being too aggressive cleaning it.
I was worried about the knob on the mother board having a dead spot at full speed.

Remove the distribution fan and clean it on the bench with a soft paint brush and low pressure compressed air and oil the bearings. Like I stated on other threads, don't matter if the bearings are 'shielded' or not, they have dust shields only and light machine oil will get right past the dust shields and lubricate the bearings.

 

[rickwai]

On high the board should be sending close to 120v to the fan terminals. That would be a quick check to determine if it is a control issue or motor issue

 

[Mt Bob]

A film of dust on the "blades" can reduce airflow by up to 1/3.Just sayin.

 

[SidecarFlip]

In reality there is no way to eliminate dust and crud buildup on either the room air blower or the combustion air blower but, a good spring cleaning goes a long way toward keeping a lid on it.

 

[SidecarFlip]

I probably should change my comment to 'going up in smoke because a shaded pole motor won't smoke unless the lamination windings get shorted. All that happens if the rotor is locked is, the laminations get warm. No smoke involved because the armature is solid and not wire wound.

 

[Iamjoefox]

Sorry for the late update. But after trying all the suggested cleaning and lubricating nothing changed. So I went ahead and ordered a new distribution blower and new board. Replaced the blower and no change. So it turned out to be the board after all. But it’s all back to normal again.
Also changed the combustion motor and fan and the door seals while everything was apart.

 

[gfreek]

Thanks for the update. My. distribution blower is sealed no lubes holes., and really no way for air flow to cool.