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Cumberland MF 3800 question(s)

Post in 'The Pellet Mill - Pellet and Multifuel Stoves' started by rodneygt, Jan 19, 2013.

  1. rodneygt

    rodneygt New Member

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    I have a MF 3800. I live in the deep south and use it to supplement my electric heat. I also have a fireplace with a heat exchanger I made. The house is about 3500 sq ft but it has many ceiling heights ranging from 9' to 20'. The room it is in is my formal den/study, which is about 16x12 with a cathedral ceiling up to about 15'. I use a ceiling fan and a pedestal fan to move the heat out.

    I bought the mf 3800 off of ebay a little over a year ago as a "factory reconditioned model". It looked and functioned as new and I had no problems with it last winter. I used the range/level settings mostly, instead of the thermostat on/off setting. I mounted the thermostat on the back top with the bracket instead of remotely. Last year i could run the temp up to the low 90s in the room per the thermostat where the mf 3800 is located. This would normally require a setting of 4-4 to 4-6. If I didn't cut it down when the temp got this hot it would typically go into overheat auger mode and I would have to let it cool - but this was no problem as I figured out how to use it and this much heat would allow me to disperse good heat into the rest of the house. And as far as outside temps, I'm talking about temps from the mid 20s to say 35.

    However, this year I've not been able to use it as effectively. When I try to run the heat this high, the fire pot usually will get full and overflow. I can usually only run up to a temp of about 80 to 82 without overfilling the firepot and having the associated issue. I can get it a bit hotter but only right after Ive cleaned the pot. Formerly I could run it up to the low 90s even if it had run uncleaned for say 48 hours.

    I live in an area where these type heaters are uncommon and few people know much about them so was wondering if anyone had any thoughts?

    It still lights and runs fine as long as I keep the settings lower. I usually clean the fire pot with a wire brush and when carbon builds up I'll chip it off. I've taken the sides and top inside panels off regularly and cleaned the outsides of the heat exchanger tubes. I've used several different brands of pellets.

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  2. Bob Sorjanen

    Bob Sorjanen Member

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    when was the last time the stove was totally cleaned? the whole exhaust system? has the combustion blower been taken out and cleaned? everytime I see a burn pot filling up it usually means an air flow problem.
  3. rodneygt

    rodneygt New Member

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    Its not been. Mostly because I'm a novice to this and don't really know how. I actually got to thinking as I typed the post that perhaps dirt daubers had restricted the airflow in the exhaust. Any advice or links would be appreciated. Thanks.
  4. Bob Sorjanen

    Bob Sorjanen Member

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    I don't know your stove in particular but others will know it. The manual states the combustion blower be taken out every year and cleaned, to do this you will need a new gasket. the exhaust pipe needs to be cleaned also. the air filter needs to be replaced. what is your exhaust set up like. more info on your setup would be helpful for people here to help you with your stove. lots on here use the Leaf Blower Trick to clean their exhaust also
  5. rodneygt

    rodneygt New Member

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    Thank you. I'll probably have a chance to disassemble it this afternoon or tomorrow. The exhaust is pretty much horizontal - about 2 feet or so out of the heater and the brick. I clean the filter. I've not cleaned the combustion motor or exhaust pipe. I dont have a leaf blower but I do have a portable air compressor that I can use as a blower.
  6. 3650

    3650 Member

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    Welcome fellow Cumberlanderererer. I have an earlier model that isn't quite as sophisticated as yours. I would start by shutting her down and cleaning out the chimney stack. If no difference, remove the combustion fan and clean the blades. Are you cleaning out all the holes in the burn pot and the removable bottom plate? I use a drill bit. Also that bottom plate user a notch on one side, it should face the door when you put it back in. That helps to keep the pot from warping, which may also be the problem. Check the pot for warpage. Keep the inner sides of the pot clean.carbon tends to build up in layers there. I use one of those oscillating cut off tools with the scraper blade attatchment for this and the bottom plate as well. It works great. You can catch those on sale at harbour freight for $20. Well worth it. If you do all of this and there's no improvement, call Cumberland. It might be a program issue. If you don't have a really good surge, power loss protector, get one. Let US know how it goes.
  7. Bob Sorjanen

    Bob Sorjanen Member

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    try cleaning all that you can not really difficult, maybe intimidating at first. your manual which I skimmed through on cleaning looks helpful. also make sure your exhaust piping is clear. I used a shop vac to suck stuff out of my venting system after I cleaned the combustion blower. made an adapter to fit my vent pipe. good luck and let us know how you make out with the cleaning. the leaf blower they hook the suction end up to the vent pipe with adapters, on the outside of house, and with the door of stove open they turn it on, NOT pointing at any thing
  8. 3650

    3650 Member

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    Loc:
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    Welcome fellow Cumberlanderererer. I have an earlier model that isn't quite as sophisticated as yours. I would start by shutting her down and cleaning out the chimney stack. If no difference, remove the combustion fan and clean the blades. Are you cleaning out all the holes in the burn pot and the removable bottom plate? I use a drill bit. Also that bottom plate user a notch on one side, it should face the door when you put it back in. That helps to keep the pot from warping, which may also be the problem. Check the pot for warpage. Keep the inner sides of the pot clean.carbon tends to build up in layers there. I use one of those oscillating cut off tools with the scraper blade attatchment for this and the bottom plate as well. It works great. You can catch those on sale at harbour freight for $20. Well worth it. If you do all of this and there's no improvement, call Cumberland. It might be a program issue. If you don't have a really good surge, power loss protector, get one. Let US know how it goes.[/quote]
    You might need a longer run on your chimney. 2 feet isn't much. I'd definately get about four more vertical feet on that. If you are careful you can get that fan out without damaging the gadket and reuse it.
  9. rodneygt

    rodneygt New Member

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    Will do. Thanks guys. We have a warming trend now. I've got several things to do this weekend. I intend to spend some time with the heater too.
  10. rodneygt

    rodneygt New Member

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    This is where my mental failures begin - and hopefully end. I clean it but I had in my mind that the bottom plate needed the slot toward the back. I suppose I forgot from last year. The front of the pot had warped out some. I beat it back and put the bottom plate in correctly. I suspect that this will fix the issue. I just clicked the ignite button so we shall see...
  11. Bob Sorjanen

    Bob Sorjanen Member

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    just remember when doing things it can be a good idea to refer back to the manual until you have done it enough and feel confident in doing it. hope that helps your problem for now
  12. 3650

    3650 Member

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    Just make sure the pot is sitting flat on the bottom plate all the way around. It's a bit hard to do but check this with it all assembled in the stove. You might need to use a small mirror and flash light to see.
  13. Bob Sorjanen

    Bob Sorjanen Member

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    rodneygt how did it work out for you is it going good?
  14. rodneygt

    rodneygt New Member

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    It seems to be going good. I ran it up to 90 this morning. It was 35 outside last night. Its warming up to 64 today. The pot was getting pretty full at 90 and I cut it back - but it had been running since yesterday morning. At some point today I'm going to give it a really good cleaning, including the exhaust etc.
  15. 3650

    3650 Member

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    You do realize you have to dump the pot after a full hopper has run through it....right?
  16. rodneygt

    rodneygt New Member

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    Yeah. This is the second winter that I've had it. I usually pull the pot and bottom plate out every day or two and wire brush them. At a minimum I dump the pot daily.

    The bottom plate was swayed down (warped) a bit in the middle (maybe an 1/8"). The pot itself - where the top front lip is had warped in about 1/8" in the middle too. I straightened both with a hammer.

    Today, in addition to cleaning the pot and plate etc, I pulled the side and top sheet metal out and cleaned the tubes. I also pulled the exhaust pipes off and cleaned those. I ran the vac in the exhaust port and did the best I could. I also cleaned out the fresh air tube. Its nearly spotless. If I have any more issues I'm going to pull the exhaust blower off and clean it, which I'll do at the end of the season regardless.

    Mine doesn't run as much as you Northern guys'. I probably burned a ton and a half last year and will do roughly the same this year.
  17. 3650

    3650 Member

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    Fuel air mixture is the only thing I can think of that might cause the pot to overtook. The only other thing would be program issues. Maybe a power surge/ loss might have happened and damaged the controller. I'm outta ideas. Hope it works itself out.
  18. Bob Sorjanen

    Bob Sorjanen Member

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    rodneygt do you have a surge protector on that stove?
  19. rodneygt

    rodneygt New Member

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    Well it seemed to burn much cleaner after I got the warps out and put the bottom plate in right. Its just not cold enough to run it hot. Its supposed to get down to freezing tonight but its in the 60s now. When I turn it on tonight I'll see how it does - It seemed fine yesterday after resolving the issues.

    I do not have a surge protector on it. But I have one I can use.
  20. Bob Sorjanen

    Bob Sorjanen Member

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    I use an isoblok2-0
  21. rodneygt

    rodneygt New Member

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    The heater seems to be burning perfectly now. So, I guess the above fixed it. Thanks everyone.
  22. FlagshipSweep

    FlagshipSweep Member

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    This is a maintenance video produced by Cumberland.
  23. rodneygt

    rodneygt New Member

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    Thanks for the video.

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