Mt vernon AE Convection blower jam?

Msedc Posted By Msedc, Dec 10, 2016 at 5:24 AM

  1. Msedc

    Msedc
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    Jan 7, 2016
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    Last night my AE was running for a couple of hours with convection blower motor at high speed based on the noise when it just stopped for 30 seconds or so then would ramp back up then stop. After a while it shut down and gave me convection blower jam error. I unplugged and plugged it back in and started up but with same ramping up and shutting off cycle of the convection blower but did not shut down. I removed the side panel on the insert and watched both the convection and combustion motors turning on and off. Does anyone have any suggestions?

    Thanks
     
  2. Lake Girl

    Lake Girl
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    Sounds like the internal sensor on the blower is picking up an overheat. When the temp drops down enough, it will start again only to overheat again. When was the last time you blew out the motor windings with compressed air? If you don't have an air compressor, the canned air they use for computers/electronics would help. Vacuum if all else fails. Dust bunnies are killers!

    Any increase in noise? It could be bearings going as well. May want to consider a replacement. Graingers may be able to cross-reference for a replacement if you run into trouble. Likely have to buy appropriate spade connectors.
    PS: Maybe not spade connectors more like a Molex! Some fancy rigging on the harness...
     
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  3. Tnoone

    Tnoone
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    Dec 3, 2017
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    New to this, but wanted to post a recent headache regarding conv blower jammed error.
    Was getting the error intermittently. Would unplug, then plug back in...seemed to work for months.
    Finally, unit would start, but when the conv blower was supposed to come on, would error and shutdown.
    I had a spare blower, put that in, and it seemed to work for a bit, then started doing the same thing.
    Figured that it was the downpipe thermal couple ....bought a new one...$72...and put that in. no luck.
    Realized that the green wire, on the harness that plugs into the conv blower, was not crimped well into the terminator. Fixed that.....still had a problem! Same error. I was going crazy! Decided to bench test the new thermal couple that I had bought. Using a meter set to milivolts jump pins in the connector and heat the ring on the other end with a lighter. You should get at least 15 milivolts. I got nothing.
    I put the old TC in and PRESTO! Works like a charm.
    The moral of the story......never assume that your new parts work.
    I hope this helps someone so that they don't pull their hair out.
     
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  4. kappel15

    kappel15
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    What year is your stove? Sometimes where the drop tube tc connects to the drop tube gets a little rusty and causes interference with the readings. Cleaning things up a bit usually helps. And keeping motors clean as Lakegirl posted is a must.kap
     
  5. Tnoone

    Tnoone
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    Dec 3, 2017
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    I'll have to find out the year....bought it in 2010. The problem that I thought I fixed yesterday has returned after a full day of it operating fine. Argh!
    I did see some rust, very little, on the drop tube. Cleaned it with a small piece of sandpaper (under the TC and snap disc) when I first began trying to diagnose. I will check again though.
    Has a new conv blower in it. Will also try to jump the overheat snap disc today to see if that's the cause. I also have a spare one of those since they're not too expensive.
    I know that the error of convection blower jammed can be somewhat nebulous in that other things can cause it. i.e. The down pipe TC. It's frustrating to say the least.
     
  6. Tnoone

    Tnoone
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    Dec 3, 2017
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    Update after jumping snap disc. Unit again threw CBJ error. Gently pushed in the TC connection on the board, unplugged and plugged back in, and the CB came on. It surged once - went to a higher speed then back down, but came on.
    The connection of the TC to the board is tight, so I'm wondering if my problem could be a bad solder joint of the pins for the TC to the board.
    I'm thinking that this might make sense since a bad solder joint could reduce the voltage sent by the TC - hotter down pipe = higher milivolts = higher fan speed. And with a bad solder joint, the voltage received by the board could fluctuate or not make it to the board at all.
    Anyone ever heard of, or experienced an issue with a bad solder joint on the board?
    It seems strange that I would experience it now, given that the unit is 7+ years old. And I'm always very careful when im anywhere near the board so that I don't weaken anything. I'm reluctant to re-solder it since it's been 20 years since I did any board soldering, and they tend to use higher temps requiring 40 watt soldering irons. But I don't want to shell out $600+ for a new board if it's just a bad joint.
    Any thoughts?
     
  7. kappel15

    kappel15
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    you can try using a tac or pin to push the "o" female fittings tighter on the wire harness,making better connection as they are a friction fit. Just don't over do it. kap
     
  8. Tnoone

    Tnoone
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    Dec 3, 2017
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    Thanks Kappel15. I will try that.
    It has been running fine all day, but I'm not overly optimistic that it will continue.
    I can't wait to finally isolate the problem.
    Will post any epiphany I have from the next check.
     
  9. Tnoone

    Tnoone
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    Dec 3, 2017
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    Stove has 7/11/08 cast into the hopper lid. I don't see a nameplate or label anywhere else.
    Still receiving CBJ error. I was able to gently adjust the female terminator for the down pipe TC so that it was tighter on the pins on the board. I'm stumped now. Nothing else for me to test or try.
    When I watch the Convection blower, at the point where it should start, it goes backwards for about 2 inches, then forward 4 inches....but won't start spinning up.
    I saw a post somewhere that said they adjusted the switch that's on the board from 1 to 2. Mine is currently set at zero, but since I don't know what the switch does, and I can't find anything online about it, I'm not going to dumbly just start making adjustments.
    Any advice on what I can try or check now? A list of things I've done/tried/checked:
    New downpipe TC.
    New Conv blower.
    Jumped snap disc wires.
    Tightened terminator on TC.
    Cleaned downpipe where TC and snap disc touch.

    Thanks,
    Tim
     
  10. kappel15

    kappel15
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    Take your left side panel off. On the control board is a white label. Tell me what rev control board you have. kap
     
  11. kappel15

    kappel15
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    It is suppose to be on 0. 1 is for Euro fuel tables, and I can't remember what 2 is for. kap
     
  12. Tnoone

    Tnoone
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    Dec 3, 2017
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    Board is 456 revC
     
  13. Tnoone

    Tnoone
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    Dec 3, 2017
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    I ordered a conv blower harness 7000-219, since it's cheap, and will try that.
    If not that, I'm looking at a new board. Will follow-up once verified.
     
  14. kappel15

    kappel15
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    Just checking. You do know you have two sets of wires going to the control board from both fans? kap
     
  15. kappel15

    kappel15
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    That is the cheapest route to start trying. You are right on harness or control board. kap
     
  16. Tnoone

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    Dec 3, 2017
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    Got the new harness. Old one was burnt on the connection that goes to the bottom of the board. I'm hoping that there's no board damage. I don't see any, but without schematics, to be able to test voltages and/or resistance, I'm "pokin and hopin". Had to clean out the female side of the connector of burned pieces. For the life of me I can't see how they'd push so much through that connection that it would actually burn the connector.
    Glad that I took the board off though. Gives me a chance to clean all of the dust bunnies from behind it.
    The good news is, through this set of repairs and previous ones, I now have a spare igniter, burn pot TC, downpipe TC, convection blower, and high temp snap disc.
    Most of the parts,....when one goes, I buy two. Because it never breaks at the perfect time, and I hate being without a spare.
    Now for a thorough cleaning as I reassemble everything.
     
  17. Ssyko

    Ssyko
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    Nov 6, 2017
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    It's not necessarily the voltage (although it can vary a little) most damage is caused by the amount of amp draw the circuit has. as a motor gets older and bearings/bushings wear it creates a heavier load in turn draws more amperage to do the same job. with everything new you should be good for a long time :cool:
     
  18. kappel15

    kappel15
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    Got my fingers crossed for ya. kap
     
  19. Tnoone

    Tnoone
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    Dec 3, 2017
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    Yeah. I was referring to the amperage. To me it just seems odd to power the fan off of the board versus using signal voltage from the board to trigger a separate power supply. Then you'd never have to worry about high amp draw on the board. I always like to keep control and utility circuits separate. Kinda like lights and outlets on separate circuits in your home.
    And yes. I'm good now, hopefully for at least another 7 years.
     
  20. Tnoone

    Tnoone
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    Dec 3, 2017
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    so that was the problem. The Convection blower harness. Running great for more than two days now.
    Thanks for the suggestions and sense check! It's much appreciated!
     
  21. Ssyko

    Ssyko
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    I agree but the masses demand faster, better, smarter, smaller, do-it for me, set-it-forget-it. Mfg. has put it all on a pcb and said ok you can Pay for it now.
     
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  22. kappel15

    kappel15
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    Glad you are up and running. Stay warm. kap
     
  23. ARGlock

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    I sure hope this Kappel15 fellow knows what he's talking about!! :) Good to see you on here Kap!!
     
  24. kappel15

    kappel15
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    I sure hope he knows what he's takin about too!Hey AR. Long time no hear. How's life been treatin ya?
     

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