422 combustion fan rattle

[bluestom50]

I finally got my 422 working great. I oiled the fan motor. Now there is an intermintent rattle sound coming from what I believe is the fan. If I hit the side of the heater near fan the noise usually goes away for a while. Any ideas of a fix without buying a new fan motor? Bushings, spacer or something? As always any help will be greatly appreciated. Thanks, Bluestom

[HayZee518]

monitor

grab the fan and see how much end play you have [push-pull in and out]. try to move it up and down or side to side to see if there is any play in the shaft. the rattle may be some loose sheet metal in the fan housing or the damper solenoid inside. the damper is a magnetic coil and plunger with a plastic paddle on it. the O ring may have cracked and is sitting on the bottom of the housing.

[hawkins111]

M422 noise

Bluestorm, Is the noise a rattle, i.e. metal to metal or is it a howling noise? Metal to metal is easy to figure out. A howl is something different. You have already heard the howl from your other posts. Is this noise the same thing? When does it come on and how long does it last. Tom

[bluestom50]

It is a muffled soundin rattle. very intermittent,sounds sort of like tapping your knuckle lightly on a wooden table,if that makes any sense. Sometimes it will cycle on and off for hours and never make the noise. Other times it is there as soon as the combustion fan turns on. Tom

[hawkins111]

thumping sound M422

Tom, That sounds like a fuel pump noise. If it is loud, the pump is not getting the right amount of fuel. If it is faint and continuous that is normal. What about your fuel system? How much fuel, how high is the tank, is the filter new??? Tom

[HayZee518]

noise

haven't thought about it but Hawkins is correct. the pump does thump when it is pumping.

[bluestom50]

I think my description of the sound wasnt too good. I think it sounds kind of like when I was a kid and pinned a playing card on my bike and the spokes hit the card. Also a little like corn popping. I have heard the sound of the pump being dry and this is much louder and more solid noise. Thanks,Tom

[bluestom50]

I found the cause. The fan shaft rattles but stops when I push the small fan towards the back of heater. Could it be a worn spacer? Tom

[HayZee518]

blower

the motor needs some end play as it seeks its magnetic center. too much and it will move in and out. that's a problem with sleeve bearings. you could try some thin copper washers.

[dfitz3390]

if i remember correctly it has plastic or nylon washers under the the end caps. i was able to rob some off a scrap motor when i had the same problem but you should be able to come up with something if you take the time to disassemble the motor and look carefully at the washers.