Noisy bearings on Oil Burner

[robbie77]

Hi
I have a noisy boiler on my Greenstar Utility 18/25 boiler. I took the motor off the back and replaced the bearing (6202zz- Thank you burnerman john ) on the fan as there was a little movement on it I also had to replace the drive cog pipe that connects fan to pump as this had snapped. It is a little quieter but still quite noisy. I can't tell if it's the fan or the pump but as stated fan one has been replaced.
Any ideas what to check next?

Thanks

 

[Burnerman]

Did you replace both motor bearings, Robbie?
John

 

[Terrywookfit]

There are two bearings.

 

[Mike2007]

I would have changed motor and pump for cost of it. Then you don't get a call back and have to work for free.

 

[robbie77]

Did you replace both motor bearings, Robbie?
John

No. Just the one I could see when I undid the back of the motor housing. Where is the other one!?

 

[Burnerman]

The second bearing is in the opposite end casting, and it’s the same type. The motors are brushless and therefore no fears to pulling them apart.
Being die cast alloy with a fairly high zinc content, the castings expand nicely with heat if the bearing is stubborn to come out.....often a hot air gun will do the job nicely.
Unfortunately with these bearings you can’t always feel for any wear, but the balls internally will have flats worn on them - hence the noise.
Just another bit of priceless information
John

 

[robbie77]

I would have changed motor and pump for cost of it. Then you don't get a call back and have to work for free.

Ah it's my house Mike so I'm paying the bills!

 

[robbie77]

The second bearing is in the opposite end casting, and it’s the same type. The motors are brushless and therefore no fears to pulling them apart.
Being die cast alloy with a fairly high zinc content, the castings expand nicely with heat if the bearing is stubborn to come out.....often a hot air gun will do the job nicely.
Unfortunately with these bearings you can’t always feel for any wear, but the balls internally will have flats worn on them - hence the noise.
Just another bit of priceless information
John

Great info John. So I need to disconnect the fan using the allen key access hole and it will be in that area? I haven't taken that bit apart yet. Wife and kids are in now so It will have to be a stealth swap out when time is right. I bought two bearings though so that's a good start.

 

[Burnerman]

If I recall correctly I think you can leave the fan on, as you’ve replaced the bearing on that end.
If you release the bolts that hold the motor sections together the other end cap should come off - and the bearing will either be captive in the end cap, or on the end of the armature.
Send is a pic if that’s confusing!
John

 

[robbie77]

Got bearings changed no bother other than a mystery spring washer!?
Where does that go?

 

[Harry Bloomfield]

Those are usually put in, to take up shaft end float. From its size and witness marks, it should be fairly obvious where it will fit.

 

[Burnerman]

Its a sprung shim and looking at the diameter of it, it should go between bearing and housing. However, if the motor spins freely on assembly I really wouldn't worry about it!
John

 

[robbie77]

Its a sprung shim and looking at the diameter of it, it should go between bearing and housing. However, if the motor spins freely on assembly I really wouldn't worry about it!
John

That's what I thought but it looked like but thought it might catch the bearing. Maybe leave it out!

 

[Burnerman]

Bearings are made to very high tolerances, alloy castings much less so. Therefore spring shims like this are used to get ideal clearances when the motor was originally built.
No matter - leaving the shim out won’t matter.
Tip of the week? When reassembling the motor, obviously tighten the screws a little at a time, evenly.
Gentle taps with a hammer around the motor body as you tighten the screws will help to centralise things and you’ll find the motor will spin freely when you’re done.
Well done for sorting this one - hopefully the motor will be quiet now!
John