P68 exhaust fan removal - help needed!

[bas157]

I've got a Harman P68 and bent a blade on the exhaust fan (the one behind the ash pan). Bent it back, turned it on and it self destructed. Got a new fan but now can't get the old one off and am looking for advice.

I remove the set screw but can't get the actual fan assembly off the shaft. Does anyone have any suggestions on how to remove it. I've put Kroil on it a few times and will probably keep doing it a few more times, hoping that helps.
I've got a pulley puller but cant keep it lined up enough for it to work, the center screw/post keeps slipping off as I try to tighten it up.

I'm afraid to try prying it off as I don't want mess anything up with the motor itself.

This is the part I'm trying to replace: part # 3-20-502221
http://www.stove-parts-unlimited.co...r-5-Double-Paddle-Fan-Blade-p/3-20-502221.htm

side note, the new one is designed a bit different and would have prevented my mistake. The one has a rivet/pin on each blade, the old one didn't which allowed half of a paddle to bend.

thanks!
Bruce

 

[bogieb]

I'm sure I've heard of others having the same issue before, hopefully one of them will show up soon.

@Bioburner can you help? or maybe @Tonyray ?

 

[Bioburner]

Can try and get a torch on the hub to get it warmed up proper and then shock it with oil.
Dremel tool with cut off wheel if above does not work.
No Dremel tool. Drill a hole in the fans hub, first with a small pilot drill than get a larger one that will get close to the shaft. Trying to release the grip the hub has on the shaft by getting the hub to break or be cut. May have to do on opposite side too.
Good luck

 

[thatguy69]

what if you used a punch and a hammer. put the punch on the end of the motor shaft inside of the stove and drive it with a hammer. fan blade should bottom out on the inside of the stove and the motor and shaft should pop out the back.

 

[Bioburner]

what if you used a punch and a hammer. put the punch on the end of the motor shaft inside of the stove and drive it with a hammer. fan blade should bottom out on the inside of the stove and the motor and shaft should pop out the back

While a lite tap or two maybe ok the probability of wrecking the motors bearings IMO are very high. If it were just a light shaft and a heavy hub probably be fine, but the opposite is true and the motor is $100
A couple drill holes is pretty fast and way less likely to shove the shaft with the armature into destruction.

 

[bas157]

Tomorrow I'll see how easy it is to drill a couple holes. I also have a mini-ductor induction heater so I may try heating up the hub with that and see if that'll loosen it up.

Bioburner, with the dremel tool, do you mean cut a groove in it running in the same direction as the shaft? I'm not sure there is clearance to do that. I can see if the flex shaft for the dremel would possibly have the clearance but kinda think even that wouldn't have the room to cut it.

I don't want to use a hammer as thatguy69 suggested as I don't want to screw up the motor! Plus more disassembly would be needed to remove the motor.

I've got a couple ideas now but if anyone else has an tips, let me know!

 

[thatguy69]

I forgot to mention take loose the 3 nuts that hold the motor onto the back of the stove,then you won't damage the motor. Have somebody hold the motor so it doesn't hit the ground when it comes loose

 

[rickwai]

heat the collar up w/ a plumber torch. then tap w/ hammer it should release. Set screw is usually the tough part.

 

[Bioburner]

I forgot to mention take loose the 3 nuts that hold the motor onto the back of the stove,then you won't damage the motor. Have somebody hold the motor so it doesn't hit the ground when it comes loose

You still are directing the impact of a 1 pound hammer into the shaft of the motor. While not immediately noticeable the bearings can score the race and make them rough and your then soon thereafter having to replace. Bearings properly replaced are pressed into the holder and should never be hammered into place.

 

[Bioburner]

Bioburner, with the dremel tool, do you mean cut a groove in it running in the same direction as the shaft? I'm not sure there is clearance to do that. I can see if the flex shaft for the dremel would possibly have the clearance but kinda think even that wouldn't have the room to cut it.

Can make the cut at a 45 to the shaft. The idea is to get the hub to release its hold of the shaft by getting it cut in two

 

[bas157]

OK, got it off. Stopped by Advance Auto on the way home and got a loaner 3 jaw puller. That did the trick!! First attempt bent part of what was left of the fan so I broke the rest off of what I could of the fan blade area. Put the puller on and it moved a bit until the center pin bottomed out on the hub. Got a small socket to basically make the center pin of the puller smaller. That bottomed out so I used a deep well socket (4mm fit in the hub hole) and that did the trick ! The new one slipped right on and off with no problem at all. Attached is a pic of what was left when I finally got it off.

Now I have to do a search and figure out why when I went to start it up, it just keep feeding pellets until they spilled into the burn pot. Never did that before! Used a propane torch to get it burning and its running fine now.

 

[Bioburner]

Try a hard reset, pulling the plug for a few minutes. Hopefully that may resolve the issue If not take a look at the boards dip switches. Couple of them regulate the start cycles feed.

 

[bas157]

It was unplugged when I was working on it. Saw it could be related to short pellets. I'm burning Barefoot now which are shorter than anything I remember burning before. No dip switches have been touched, so hoping it is just pellet length.