Mt Vernon AE - "Conv Blower Jammed" error msg, will call svc rep asap but would like to hear of anyo

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Macrovertigo

New Member
Jun 30, 2008
44
Southeast Vermont
edhuse.com
I have a Quad Mt Vernon AE about two years old, has always run well, this is the third Winter for it. Today I tried starting it up, after a little while it shut down and game me the reading - "Conv Blower Jammed". Of course, now that I have opened it and found nothing unplugged or otherwise obvious or simple to fix, I will call svc rep tomorrow, but would like to hear of anyone else's experience or thoughts on subject. The convection fan rotates freely, but just doesn't seem to get any juice.
 
Do you have the manual?

I think it could be the 125º snap disc. Unplug the stove and try jumping the snap disc(connect the 2 leads together). Plug the stove back in and see. If the fan runs thats the issue. But it probably will not shut off until you unjump the switch.

Remember to Unplug the stove anytime you play around back there!
 
Hi thanks for the lead, I will forward your clever and appealing idea to the tech but won't try it myself, since I am no electrician and this sounds like something right out of Murphy's Law playbook, lol. Thanks for your time.
I will post results of service call ...
 
Macrovertigo said:
Hi thanks for the lead, I will forward your clever and appealing idea to the tech but won't try it myself, since I am no electrician and this sounds like something right out of Murphy's Law playbook, lol. Thanks for your time.
I will post results of service call ...

Just so you know, what Jay suggested is a well proven method of ruling out one of several likely possible causes of your situation and it is likely that the tech is not an electrician either.
 
This is a Mt Vernon AE, no snap disc to jump in line with the conv blower. More than likely the blower or control board has gone bad or the blower actually is jammed. This blower is controlled by the thermocouple on the back of the feed system drop tube.
 
If it is a tried and true test I will remember to try it, but sounds like my pellet stove doesn't have it, it is a mt vernon AE for sure (thanks balls of fire) - if the squirrel cage in the convection blower rotates freely with no sounds or anything, does that mean it has no obstruction?
- if the control board was bad wouldn't the whole unit refuse to go on in the first place?
 
balls of fire said:
This is a Mt Vernon AE, no snap disc to jump in line with the conv blower. More than likely the blower or control board has gone bad or the blower actually is jammed. This blower is controlled by the thermocouple on the back of the feed system drop tube.

is the thermocouple controlling the blower something that I can see with the case panel off? Could I have knocked it loose with the vacuum cleaner when I was reaching in there from the combustion fan side?
 
Macrovertigo said:
If it is a tried and true test I will remember to try it, but sounds like my pellet stove doesn't have it, it is a mt vernon AE for sure (thanks balls of fire) - if the squirrel cage in the convection blower rotates freely with no sounds or anything, does that mean it has no obstruction?
- if the control board was bad wouldn't the whole unit refuse to go on in the first place?

The portion of the control board that controls the fan or reads the sensor could be bad and the rest of the system could still work.

The fact that a thermocouple is being used to indicate a mechanical problem is rather interesting and it also means that the blower can be perfectly fine and not jammed.
 
Macrovertigo said:
balls of fire said:
This is a Mt Vernon AE, no snap disc to jump in line with the conv blower. More than likely the blower or control board has gone bad or the blower actually is jammed. This blower is controlled by the thermocouple on the back of the feed system drop tube.

is the thermocouple controlling the blower something that I can see with the case panel off? Could I have knocked it loose with the vacuum cleaner when I was reaching in there from the combustion fan side?

If you managed to hit a thermocouple you could not only knock it loose you could depending upon how it is constructed damage it.

Do you have the manual for your stove?
 
Hi, I have the paperwork that came with the stove, it has a trouble shooting area with no mention of convection blower probs that I can find, and there is a piece on changing the convection blower but it doesn't go into why or when I would want to do that. There is no section to help me diagnose the problem, but I would bet I probably could figure it out if I had the right reference materials, since there is a raft of lights and controls visible above the convection blower when I take the panel off to look at it.


j-takeman said:
Do you have the manual?

I think it could be the 125º snap disc. Unplug the stove and try jumping the snap disc(connect the 2 leads together). Plug the stove back in and see. If the fan runs thats the issue. But it probably will not shut off until you unjump the switch.

Remember to Unplug the stove anytime you play around back there!
 
Did you unplug the stove to clear the error and retry? When I have seen this error that is one of the 1st things to try but in those few cases I have always had to change either control board or blower. FYI page 29 should show conv blower troubleshooting.
 
balls of fire said:
Did you unplug the stove to clear the error and retry? When I have seen this error that is one of the 1st things to try but in those few cases I have always had to change either control board or blower. FYI page 29 should show conv blower troubleshooting.

Hi, yes, I retried a couple of times in case something felt like "clearing" but no go, - Oh yeah, I did find that trouble shooting pointer on page 29 fight away when I first tried to deal w prob, but it did not help and now here am I last on my service providor's list, har har (no problem with heating the oil burner is still the primary heating thing)
 
I agree, the owners manual doesn't shed any light on your problem. If I were troubleshooting I would test the thermocouple first and then move on to replacing the blower. If changing the blower doesn't do the trick the control board is faulty. How old is your stove, did you get it Oct of 09', what is the manufature date? There are some updates that could be done when they come out to service it depending on the age of the stove.
 
balls of fire said:
I agree, the owners manual doesn't shed any light on your problem. If I were troubleshooting I would test the thermocouple first and then move on to replacing the blower. If changing the blower doesn't do the trick the control board is faulty. How old is your stove, did you get it Oct of 09', what is the manufature date? There are some updates that could be done when they come out to service it depending on the age of the stove.

this Mt Vernon AE was manufactured in Nov of 2008, I will ask about updates - do you know if this machine is on any list for any particular updates?

With the thermocouple (when I locate that, har har) do I just test to see if it is getting current with one of those circuit testers?
 
SmokeyTheBear said:
By any chance did the stove actually light?

The stove does light up fine as usual. In fact, a little while ago I plugged it in again, and the blower fan actually turned on for about a half a minute before stopping, and this time the stove shut down within minutes - in the other tests today and yesterday, when plugged in, it starts up, burns bright and then after about ten minutes or so shuts down. This was different as the convection blower could actually be seen to go on for a few seconds. Sound like a bad snap disc switch or sensor of some kind?
 
Macrovertigo said:
SmokeyTheBear said:
By any chance did the stove actually light?

The stove does light up fine as usual. In fact, a little while ago I plugged it in again, and the blower fan actually turned on for about a half a minute before stopping, and this time the stove shut down within minutes - in the other tests today and yesterday, when plugged in, it starts up, burns bright and then after about ten minutes or so shuts down. This was different as the convection blower could actually be seen to go on for a few seconds. Sound like a bad snap disc switch or sensor of some kind?

According to the manual your stove should indicate a bad thermocouple, so I would assume that the thermocouple is fine (this is not to say it isn't loose or out of position).

Since you just verified that the convection blower started I'd say that it is possible that the convection blower is seizing when it gets warm. This could be due to a bad bearing or lack of lubricant. Does that blower motor have oil ports? If so find out what oil the manufacturer recommends and try re-lubing the motor.
 
You can test the thermocouple with a multimeter that has a millivolt setting. The themocouple needs to be disconnected from the control board, connection is delicate so be careful, once disconnected remove the TC by taking the wing nut off drop tube. TC should be able to be removed now. Heat the ring end of the TC while taking a reading on the connector end of the TC. Should get 15Mv in a short amount of time. If not TC is bad. Wall control should display bad droptube tc if it is bad though.
 
Hi all, here is the result of the service call (from HB in Springfield, Vermont) that has resulted in successful resolution of Conv Blower Jammed error msg hold-up:
1) they changed the convection blower and it now runs normally (like a champ), and:
2) thermocouple was indeed fine, and now I have a more thorough understanding of what it is to be a thermocouple in the modern world (and more importantly, how to take care of it), and;
3) regarding where the failure to heat ocurred, HB had to assume that the problem resided in the convection blower itself, specific details unkown without a tear down of course, but all other obvious variables tested fine, and of course there was no other error message at any time.
4) Even though HB is my original seller, installer, and service agent, and even though beyond being way capable they happen also to like the Quadrafire products, even so it was of great utility to HB (and to me) to have access to this conversation.
Thank you Hearth.com/Forum members for your time and trouble!

I am not including photographs, as I saw nothing of note that anyone would find remarkable. I say this because it was neat and clean inside - even the inside of the combustion exhaust fan casinghad only a minor build-up of (black) matter, (not much considering it has not been opened since it was started up two years ago). There was nothing out of place, the wiring was all very neatly arranged and tied up, there was no gross build-up or matting of dust or debris, I tell you I didn't even drag the camera out for this. The guy was here working on it for less than an hour, everything is copacetic.

One thing that I will post in the Spring is before and after photos of cleaning off the smoke deposit on the outside of the house - I just cleaned and painted with a teflon-based paint and all I dream about is watching it self-clean in a Spring shower, but I will be glad if it washes off with the garden hose. I have hope, the other day I watched as a spider struggled futally for footing for a half hour, he never had more than two feet at a time able to purchase any kind of hold, and he finally gave up.
 
Apparently, the thermocouple is just a wire, so you have to avoid stressing it and snapping it, especially where it is held by a connection (the point where the connecting piece of metal is crimped to the wire is a point where the wire's structural integrity could be compromised, and if the wire is "worried" back and forthe by ham-handed probing about or use of vacuum cleaning tools, that is a good place for it to snap). That is just my impression as a well-intentioned amateur.
 
thanks thats what I thought but after reading your post thought i was missing something. Here is a little info for you. After a thorough cleaning @ the end of last year I noticed some deterioration of the thermocouple cover (ceramic piece). I heat our entire house (2900 sq ft)with our AE it burns almost continously during the heating season. This is our 3rd season with unit. I am now going to rotate the thermocouple cover annually. I hope this will prevent any premature errosion of the cover. To rotate the cover you can simply loosen the bolt that holds the thermocoupler in place and turn cover.

Anyone have thoughts on this?
 
Thanks, you reminded me that there are two things referred to as thermocouples. I was referring to the wire that is attatched to the drop tube, inside the back workings of the unit, it sends a signal to the convection blower fan. You have brought up the ceramic thumb thing that sits over the fire pot, thank you for that clarification and good hint - about that ceramic cover, my technician recommended getting a small wire brush to delicately clean accumulations from it. He says that the literature says that it is not important to do so, but his theory (and I agree) is that any deposits on that ceramic thermocouple cover over the burn box, will act as an insulator and could give a false reading.
 
I don't think their should be any maintainence involved with your drop tube TC. As far as the firepot TC goes, the little bit of ash that would build up might give you a couple degrees differance in temp reading which would not worry me too much.
 
I was probably exagerating for effect when I was blathering about the thermocouple (it is all new to me, love the term), but thanks for centering my comments - no need to fall accidentally into a TC maintenance routine where none is necessary, har har.
 
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