HotDawg fan problem

[Mainiac Mat]

This one is an oddball....

I installed a Modine HD60 one year ago... barely used it last winter. Sat idle (power and gas shut off) all summer. Fired it up again a month ago and it worked fine until Thanksgiving.

The first hint something was wrong was the fan started making more noise than usual. Then the next day then the fan wouldn't start. But here's where it get interesting.... The timer relay sends power to the fan. But the fan won't start. But if I give the fan a nudge with a stick, it spins right up and runs as before (noisy).

Sounds like the starting capacitor failed, right? So I grab a known good cap from work... exact same rating and test it out. No start... but again, will run if I give it a push.

My best guess is that there is a centrifugal switch inside the fan case that cuts the starting cap out of the circuit when the fan spins up to full speed and that this is stuck in the "at speed" position.

I submitted a warranty claim with the distributor I purchased the unit at, but the unit just tripped the one year mark a couple days after if failed, and now I suspect they're going to weasel out of replacing the motor, because I'm not a bonified tech. (just a lowly engineer).

Next trouble shooting step will be to give the case a rap with a hammer.

Any other thougths?

A replacement fan is $130... and I'd rather not go there.

 

[gmcgeo]

modine has a 10 year warranty on chamber and i think 5 year on electrical. The will replace the fan assembly if you bought it new last year

give me a min and ill double check

 

[gmcgeo]

https://cdn.gateway.acpro.com/documents/Modine_Natural_Gas_Unit_Heater_Warranty.pdf

should be a 2 year on the fan

 

[FredWanaker]

fan bearing is what it sounds like.

 

[PoorUB]

Does the fan motor turn hard with the power off? And if it does, perhaps you can get oil to the bearings. Pretty sure they are bushing motors so oiling might do it.

 

[Mainiac Mat]

Thanks for the replies...

The fan turns freely when I spin it. Then, when it's running the sound isn't howling or squealing. but it's definitely louder and different than it was.

I purchased the unit online from Northstock (aka H-Mac Systems) in Mass. and went through their on-line warranty claim process. They directed me to Modine tech. support, and after agreeing that is sounded like the fan was bad, the guy directed me to the Modine distributor in my area (a large plumbing/heating outfit who typically only sells to HVAC contractors... not who I bought it from) to determine if it was covered under warranty.

So I replied to Northstock that I bought the unit from them and wanted to deal with them and not the NH distributor... and much to my pleasure, they jumped right on it and are shipping me a replacement fan (in-stock) at no cost to me.

I'll let you all know how it works out when I swap the fan.

 

[D45]

Nice. Hopefully the new fan solves the problem

 

[LS6 Tommy]

The fan motor in that unit doesn't have a centrifugal switch, it's a Permanent Split Capacitor motor. If a new run cap didn't solve it, the motor windings area probably bad.

Tommy

 

[Mainiac Mat]

Permanent Split Capacitor motor

And now I've learned something new today... so it was worth getting out of bed

 

[Mainiac Mat]

The replacement motor from Northstock (aka H-Mac Systems) was delivered and I finally got some time to install it Saturday.

I wanted to warm up the garage for the occasion, so I fired up the unit, but forgot that I had removed the capacitor from old motor as part of my trouble shooting. After reading up on Permanent Split Capacitor motors and learning that the cap doesn't cut out with a centrifugal switch, but remains in the loop 100% of the time, I didn't think the motor would run. But since I really didn't want to work in the cold, I waited for the relay to send power to the fan and gave it a push with a slim stick... Voila! It started up and ran just fine.

After getting the garage warm, I shut the heater off and cut power and swapped out the fan motor.... easy-peasy. A half hour later, the heater was back to normal and the motor was running much more quietly.

So there you have it. When I get some down time, I'll dissect the old motor and post pics. Maybe I can even heal what ails it and store it for use as a spare.

 

[gmcgeo]

happy they took care of you warranty wise.