PDVC 25 unburned pellet build up

[Jigger]

Over a month ago I did the leaf blower trick to my stove and chimney. I pulled combustion blower off just to see how clean the leaf blower cleans out the stove.It does do a wonder job of getting the ash out. I used a small brush and cleaned the area.
But within the last 2 weeks I've been getting some serious build ups of glowing sunburned pellets in the pot.The combustion blower seemed to be working well and had no noticeable noises coming from it So I ordered a new combustion blower which came in the other day. Yesterday was a warm day so I shut the stove down. But when I got home from work it was to late to try and replace the blower. So I started the stove up again with the door open to see if I could hear anything going on. After running for a few seconds I heard a noticeable change in the pitch of the combustion blower. So today I shut the stove down and changed out the combustion blower. I took at old blower and spun the fan and it moved freely. But you could hear a sound like that of a dry bearing. The new combustion blower has been running for the past 9 hours and there is no more build up of glowing pellets.

 

[SidecarFlip]

replace the bearing in the old combustion blower. You will have to soak the set screw on the fan for an extended amount of time with P Blaster or a good alternative solution like acetone / ATF mix to get it to free up however. Nothing last forever (bearings) but the rest of the unit (motor itself, armature and laminations) will outlast the bearings. Disassemble it and not the etched in numbers in the bearings and get them from a bearing distrubutor or on line and replace. I get mine from Detroit Bearing, Applied Technologies.

 

[MalcolmH]

I always wondered if the combustion blower should be taken out for the leaf blower trick, or locked down so it doesn't spin faster than was intended or designed to.

 

[SidecarFlip]

Don't matter one way or another. I only take mine out at the end of season when I do a deep clean and then I clean the blades (carefully) on the combustion fan with a small paintbrush, check the bearings, oil them or replace them as needed and reinstall the combustion blower. You sucking on the venting with a leaf blower won't get the combustion fan spinning fast enough to damage it.

The combustion blower gasket (for me) is optional. I put a bead of red high temp silicone around the mating surfaces and let it cure. For me, that eliminates the gasket replacement issue but how I roll, you may have a different outcome.

 

[MalcolmH]

I dunno those little skate board bearings aren't very big, you wouldn't want to run a leaf blower very long or you'll be replacing bearings steady and become a pro at it..

 

[Ssyko]

Air flow through the blower won’t spin it up to much because the blades are not pitched, they are paddle type. Centrifugal force from the paddles move the air. And there is a lot of space around them that air can go by without affecting them.

 

[SidecarFlip]

I dunno those little skate board bearings aren't very big, you wouldn't want to run a leaf blower very long or you'll be replacing bearings steady and become a pro at it..

Those 'little' skate bearings will take in the excess of 25,000 rpm, way more than any leaf blower is capable of sucking them to...lol Removing the combustion blower unit for a suck job is false economy and wasted time unless you are performing a end of season deep clean.

As an aside, when I pull mine to clean the fan blades, I'll brush them off and then take an air nozzle and blow the soot off and many times, I've 'spooled' the fan up considerably with the air nozzle. While I don't endorse that or recommend it, I've never encountered an issue with the bearings or the fan for that matter.

 

[MalcolmH]

Thanks guys, I'll put those concerns to bed. It's good to note that not all bearings are equal or capable of spinning at 25,000rpms, some are plastic caged bearings, and some have different shielding, not all bearings of the same size are the correct type for small light duty fans in our application or capable of spinning at 25,000rpms, I always replace my bearings with steel caged bearings with metal shielding.

 

[SidecarFlip]

Don't believe you'll find Delrin or nylon bearings in any motor in any appliance. Maybe 660 CA oil impregnated bronze but usually shielded ball of import manufacture.