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Ron Burgundy · 01-21-2017, 10:37 AM

I use my suburban NT-34sp furnace extensively and would like to do some preventative maintenance. It's working well but is original to the coach so I would like to do a little overhaul. The only observation I've made that's out of the ordinary is that every once in a while I hear a small chirp (I'm guessing from the motor/bearings). That said, here is what I have slated to replace:

1) motor assembly
2) limit switch
3) sail switch.

Anybody have any additional parts that they would recommend replacing while I have the unit apart?

BFlinn181 · 01-21-2017, 10:54 AM

Not sure a 'chirp' is a motor bearing, it could be one of the squirrel cage fans rubbing on sheet metal. A bad bearing is usually a longer, sustained squeal.

The sail switch is a pretty simple switch, I'm sure designed for millions of cycles. I don't think it needs replacement until bad. The limit switch can go bad, but again, do you have any indication it's failing? If you're just replacing these components because plan to dismantle for motor exchange, I'd suggest Murphy's law and it's corollaries that once it's back together, something else will fail.

Ron Burgundy · 01-21-2017, 11:21 AM

I'm with you on Murphy's Law....that's exactly why I plan to place the sail and limit switch even though they are not failing. Plus, they are about $10 each...cheap insurance! Just wanted to see if anyone had any other parts they'd throw in that category.

I do on occasion get a squeal that is sustained but it goes away soon after it starts. Figure that the fan motor is at the heart of the system and an update would be wise.