Mt Vernon burnpot door won't close completely in autoclean cycle

[olssons]

Hi All,
I bought my Mt. Vernon in November 2013 and since then had little problems with it. I clean it weekly and then clean the whole system every summer. I burn Turman pellets.

Starting at the beginning of this season, I've noticed that the burnpot door doesn't close completely when an autoclean completes. I tried to throughly clean the burnpot. Still the same problem. I then greased the slides on the autoclean and it now autoclean runs without hardly any noise. Still the problem persisted. I took apart the autoclean and reassembled... nothing changed. I then pulled the whole stove out and took a look at the autoclean motor assembly from the back side. I couldn't find any loose screws (as another posted suggested) but there was some dust in here so I cleaned everything out really well. Still the problem persisted.

When I run the autoclean cycle it seems to run fine right up until about a half inch from being completely closed. It then seems to stop short of fully closing. I can easily push it closed with my hand.

The stove still seems to work fine, just the burn put is slightly open which causes some partially burnt pellets to sometimes drop into the ash pan. Other than that, i don't notice any difference so far.

I appreciate any help you can give.

-Sten

 

[Lake Girl]

Welcome to the forum! From what I've seen so far, most often it is carbon build-up on the mating faces on the pot. Have you taken out the pot and tried scraping, wire brush, steel wool, etc. to get it cleaned up? PB Blaster first then extreme graphite once done on the pivot point may help it move easier. Need to be careful of the thermocouple ... but you know that

 

[kappel15]

As Lake Girl commented on of carbon buildup on the pot floor. Also, pull the ashpan and make sure the mounting bolt that holds the auto clean motor in place is tight. This happened to mine once. It is right behind ashpan. Tightened it up and good to go. Also, what rev. control board do you have? kap

 

[olssons]

Welcome to the forum! From what I've seen so far, most often it is carbon build-up on the mating faces on the pot. Have you taken out the pot and tried scraping, wire brush, steel wool, etc. to get it cleaned up? PB Blaster first then extreme graphite once done on the pivot point may help it move easier. Need to be careful of the thermocouple ... but you know that

I cleaned the bottom part of the pot (which can be removed when you disassemble the autoclean mechanism). This is now shiny metal I haven't done extra work on the mating edge so I will try that. I have a wire brush I can use and hoping there is something there. I'll keep you posted. Thank you!

 

[olssons]

As Lake Girl commented on of carbon buildup on the pot floor. Also, pull the ashpan and make sure the mounting bolt that holds the auto clean motor in place is tight. This happened to mine once. It is right behind ashpan. Tightened it up and good to go. Also, what rev. control board do you have? kap

I have tightened the mounting bolt a few times and tight. I noticed there is some play in this connection in general. I assumed it was because they want to make sure it can swivel without issue. I will check the bolt again and retighten if necessary. My board says manufactured in 41/12 which I assume is April, 1, 2012. It's a REV C board. Thanks for taking the time to help. -Sten

 

[olssons]

On the far left of this photo, you can see a small opening that is left after autoclean completes.

 

[olssons]

On the far left of this photo, you can see a small opening that is left after autoclean completes.

OK, I scrubbed the pot again. The autoclean is now pretty much noiseless except for the sound of the motor itself. I also tightened the bolt going to the autoclean motor one more time. I'm afraid if I tighten it more, I'll snap it Still, just at the very end of the cycle it kind of slows and seems to stop early, which leaves the opening. I can't imagine I need another motor though at this point, I'm not sure what else to do. Maybe replace the autoclean springs?

 

[Lake Girl]

If it is anything like the door handles on back doors/hatches on GMs, that would be my next thought A $40/50 dollar part for want of a good spring

 

[kappel15]

The springs don't have anything to do with pot floor closing all the way. They just hold the pot floor tight against pot. You said you have taken auto clean all apart. Is the pot floor arm set screw tight, holding it in place? There is a micro switch on the auto clean motor too, that could be dirty, or going bad. Or the motor is going bad. kap

 

[olssons]

The springs don't have anything to do with pot floor closing all the way. They just hold the pot floor tight against pot. You said you have taken auto clean all apart. Is the pot floor arm set screw tight, holding it in place? There is a micro switch on the auto clean motor too, that could be dirty, or going bad. Or the motor is going bad. kap

kap - Sorry for the late response. When you say set screw, I'm imagining something with an allen wrench fitting. The only screw/bolt with autoclean that I currently know about is the one that connects the autoclean motor arm to the pot floor arm. Yes, this bolt was tight and I tightened it more now. Is there another screw somewhere I could have missed?

I should have read this last night because I have now put the stove back inside the chimney . What does the microswitch look like? I'll look online to see if I can find some diagrams. I couldn't see anything that looked like a sensor when I took off the convection fan and looked inside. I vacuumed this area out because it did have a lot of dust in it. Maybe the switch is dirty. I just need to find it. I hope it's not the motor because the stove isn't very old. The microswitch thing sounds promising.

Thanks a lot for your help and suggestions. - Sten

 

[Lake Girl]

http://downloads.hearthnhome.com/serviceParts/Mt_Vernon-AE.pdf page 5 shows the autoclean and microswitch part 7000-327

Did you blow out motor windings with compressed air or at least vacuum?

 

[olssons]

http://downloads.hearthnhome.com/serviceParts/Mt_Vernon-AE.pdf page 5 shows the autoclean and microswitch part 7000-327

Thank you! I see where it is now. On paper at least... now to figure out how I'm going to get to it and clean it Last time I pulled the stove out and removed the convection fan to look at the autoclean motor.

 

[Lake Girl]

I hear you ... everything looks easy on paper. Part of the reason I don't attempt to mess with the cars anymore ... have to move the XXX to work on YYY

 

[kappel15]

motor behind plate. need board off I think sorry typing just had roto cuff surgery hard type one hand slow too kap

 

[olssons]

Here is my autoclean motor and microswitch. It wasn't as dirty as I had hoped it might be. I'm cleaning it off with a brush some more, going to try to see if it did anything, but not hopeful. BTW, if you look how the switch and motor arm is sitting in the picture, this is where the arm stops during my autoclean. Does it look right? Not sure you'll be able to answer, but I figured I'd ask

 

[kappel15]

can see set screw in pic do u? drugs settin in getting tird sorry kap

 

[olssons]

can see set screw in pic do u? drugs settin in getting tird sorry kap

Yes, I see it. That's tight too.

 

[Lake Girl]

can see set screw in pic do u? drugs settin in getting tird sorry kap

Take care of you kap ... surgery is never fun but hope it fixes the damage. Need to get you Naturally Speaking software that will type for you

 

[Lake Girl]

Wondering if the auto clean can be powered from outside power source ... like exhaust blowers? May make troubleshooting easier

 

[olssons]

Feeling the microswitch with my hand just now, it is not 100% snug in its place. Don't get me wrong, it's not really what I would call loose, but it just moves slightly (maybe a millimeter at most). I'm wondering how it is fastened and whether this would be normal or not. I suppose I would need to take the autoclean off to see how it's tightened if at all. Don't think I'm up for that tonight

 

[FordMastertech]

I have had this AE insert since 2006 and had to modify some things along the way and one of them was the auto clean floor not closing all the way. I pretty much inspected everything found nothing loose or worn so I took the linkage that connects the auto clean motor arm to the burn pot floor out and shortened it up about 3/8 of a inch by putting it in a vice and hammering both sides of the arm ends closer together. It was very easy to remove the linkage through the ash door opening by removing the 2 bolts. I have also had to replace the burn pot floor springs a couple of times that caused sagging and a excessive gap between the floor and burn pot, somewhat of a PITA repair.
Kap take care of that shoulder I have had both sides done now, one side went well the other was not repairable and it not a fun recovery.

 

[Lake Girl]

Mastertech, Thanks for the info on the mods you've done! Not so glad to hear surgery didn't help the shoulder...

 

[olssons]

I have had this AE insert since 2006 and had to modify some things along the way and one of them was the auto clean floor not closing all the way. I pretty much inspected everything found nothing loose or worn so I took the linkage that connects the auto clean motor arm to the burn pot floor out and shortened it up about 3/8 of a inch by putting it in a vice and hammering both sides of the arm ends closer together. It was very easy to remove the linkage through the ash door opening by removing the 2 bolts. I have also had to replace the burn pot floor springs a couple of times that caused sagging and a excessive gap between the floor and burn pot, somewhat of a PITA repair.
Kap take care of that shoulder I have had both sides done now, one side went well the other was not repairable and it not a fun recovery.

That's a good idea... I'm going to try it Unfortunately I was down to check my workshop yesterday and someone (one of my teenagers) had broken my vice. Ran it all the way out and now the screw part won't go back in. I can't tell you how many times I go to use a tool that I don't use often and there it is, lost or broken

 

[Lake Girl]

Had the same problem with my kids and tools ... I became a secret tool hoarder! Let us know how you make out... with the mods. You're on your own with the kids!

 

[olssons]

Ok, I tried it tonight and when I first measured the arm, it was 11.5 inches. I bent in each end 1/4 inch so now the arm measures 11 inches exactly (end to end). I put it back in place and tightened the screw and... WORKED LIKE A CHARM My burnpot door now closely properly .

I am wondering if the action of pulling the burn pot bottom shut when the stove is hot (i.e. during autoclean) caused the arm to bend slightly outward over a few years time. I always burn on Manual High so the stove always gets as hot as it can get which may contribute to this.

Anyway, I'm not sure what happened to the arm, but it did appear like it had become longer than it was supposed to be (which causes the problem). I did see the straight, middle part of the arm was slightly bent outward when lying it against something flat. I thought about trying to bed this part back, but decided it would be easier to bend each end instead.

Thank you, Lake Girl, Kap, and FordMastertech for all your help. I was going to give up soon and I'm glad I didn't have to do that!

-Sten

PS - I fixed my vise while I was at it!