Froling draft fan noise, bad cap

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__dan

Feeling the Heat
Oct 5, 2011
331
Put the Froling in service about 2012 and in the first year the draft fan started making a high pitched noise. I thought it was an early bearing failure but I just kept running it, figuring it would quit eventually and I would need a new draft fan, for $$$. When new I could not hear the draft fan even standing next to it (at low speed). The whine I could hear upstairs.

It got progressively worse and started having trouble with torque at startup, again thinking from the noise it was the bearing. Was going to buy a spare because of the having heat in the winter. It was going to quit permanently pretty soon. Tried looking up the Lafert motor but could not find it online.

So I got an inspiration, or a brain fart, maybe it could be a cap. I just had a bunch go, the well pump cap went, new one was $11. The control board for the Electrolux washer went, new Ebay board brought it back to life for $130. (caps on the boards go).

So I checked the Froling draft fan motor and it has a run cap. It was hard to source online but Digikey has them by matching the spec, 450 Volt 6.3 uf polyester film type motor run cap, not an eletrolytic.

Digikey to the rescue. Just put the new cap in and the bad bearing sound is gone, after almost ten years of planning to buy a new draft fan.

Picture of the old cap. Supposed to be 6.3 uf on the meter, which the new one is.

Very happy, the Froling is a lifesaver. Posting this in case someone needs it. If the draft fan loses torque and makes a high pitch bad bearing sound, try changing the motor run cap.

PART: 399-C276CC24630AA0J-ND MFG : KEMET / C276CC24630AA0J DESC: CAP FILM 6.3UF 5% 470VAC RADIAL ($4 cap plus $5 shipping).

bad cap.JPG
 
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