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Need Help, Napoleon NPS40 Convection Blower Fan

Post in 'The Pellet Mill - Pellet and Multifuel Stoves' started by becasunshine, Dec 18, 2012.

  1. becasunshine

    becasunshine Feeling the Heat

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    GREETINGS, PELLET HEADS! Long time no see- I haven't been around here much! Still lovin' life with the Napoleon Pellet Stove. (To those of you who espouse insulation, we had our attic insulation beefed up a couple of years ago, and yeah, the Napoleon puts out enough btu's to run us out of the house now that we aren't wasting btu's through the roof. So kudos to you, Insulation People!)

    Anyway, we are having some issues with our convection blower fan. We've researched this online, and it appears that my husband has found internet posts that describe this problem, but we want to put this in front of knowlegeable eyes before we start ordering parts.

    The convection blower fan is working, and it isn't making any unusual noises. It appears to have a reostat problem, however. We will sometimes leave the convection blower fan OFF for a few minutes when first starting the stove in order to let the convection tubes heat up before we start pushing fresh air through them with the convection blower fan. Typically if we wander off or are busy with something else, the over-heat override switch will kick in and cut the fan on before the stove overheats. We aren't sure about this, because we haven't yet allowed the stove to go through its full overheat safeguard cycle in which the stove shuts completely down if the convection blower fan doesn't cut on to push the heat out- but there's been at least once (just now) when we expected the fan to just cut on, already. (I know, we need to do the complete controlled experiment and see if the stove shuts itself down.) Anyway, we expected the convection fan to cut on- and it did not- so we turned it on.

    This we do know: our convection blower fan cuts on via a knob that clicks "on," and when it clicks "on" it is in the high setting of 5. We can then turn it down from there. If we turn the fan "on" and dial it immediately down to say, 3, the fan does not come on at all. The motor hums but the fan doesn't come on. If we dial it back to 5, or high, the fan will come on. If we then turn it down to 3 (or whatever, anything below the 5 setting) the fan will stay on- but we have to let it come on at the high, or 5 setting, or it won't come on at all.

    Our question, before we start ordering replacement parts: do we need an over-ride switch (guess we need to do the "Does the pellet stove shut down because the override switch didn't work?" test to know that) or do we need a high limit switch (ditto test) or do we need a whole new convection blower?

    What say you, Wise Ones? oh and HAPPY HOLIDAYS, EVERYBODY! :) :) <:3~ =:X

    P.S. Amended to say, we have shut the stove down so we can test the various switches. We'll cut it back on, let it fire up, and see if the override switch works. We'll see if the high heat switch cuts on before the override switch cuts on.

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  2. becasunshine

    becasunshine Feeling the Heat

    Joined:
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    438
    Loc:
    Central Va
  3. becasunshine

    becasunshine Feeling the Heat

    Joined:
    Dec 10, 2009
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    Loc:
    Central Va
    P.P.S. Replying to my own post to say that the override switch worked, and the fan did cut on, even though we had the fan knob turned to OFF. Fan continues to work when we turn it ON to 5. It appears that we've isolated the problem to turning the fan ON and immediately down to say, 3, as opposed to 5 or HIGH. The fan does not always work at that setting initially- the motor hums but the fan doesn't blow. We have to turn it to 5 or HIGH, at which point the fan begins to work- then we can turn it down to any setting and it will continue to work. Is this a fan problem, or a reostat problem? And regardless, will replacing the convection blower fan unit take care of it by replacing both the motor and the reostat?
  4. stovelark

    stovelark Minister of Fire

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    Good troubleshooting skills sounds like the fan needs the extra voltage (having to put it on setting 5) to get it started. After its initial starting, then you can lower it to the lower settings and it stays running and the blower slows down accordingly it sounds like(?) that sounds like a blower that needs cleaning and/or needs oiling if possible, see if anything is caught or keeping it from turning, or its time to replace said blower. A visual check too is in order, and see how the motor turns by hand- that will let you know about the bearing condition usually... sometimes a good cleaning is all that is needed. We had a couple of Napoleon convex blwr needing replaced this year, the units were all 3-5 seasons old, a replacement if needed is around 200 bucks. The rheostat is prob ok, most of the time they either open and no speed adjustment is possible and the blower will not run at all, or they fail in one spot so no adjustment of speed is possible. If replacing both gives peace of mind do it though I don't see the need for it. good luck

    Stovelark
    Enviro EF3 FS pellet
    Enviro Empress FPI AC
    Enviro Kodiak 1700 FS wood
  5. becasunshine

    becasunshine Feeling the Heat

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    Thank you, Stovelark!

    The low temp switch and the override switch appear to be working as intended. We've not had a "test" on the high temp switch because the override switch cuts the convection blower on.

    My husband pulled the convection blower unit yesterday, vacuumed the insides, oiled it in the appropriate ports, and reinstalled it. It wasn't all that dirty; we have a professionally installed fresh air intake with a screen over the outside terminus. He had previously made sure that the screen was clean; it was. (It has a protective plate/cover over it; it is part of a professionally fabricated and installed metal device that also includes the terminus of the exhaust pipe.) So, we aren't pulling in "room air" and thus we have lowered the material available to make dust bunnies.

    Also, we have a 75 lbs. Labbie and a 20 lbs. cat, both of whom shed like that's their jobs. We vacuum DAILY. And I've always vacuumed the blades of the convection fan when cleaning the stove guts, and it's *never* been the least bit dusty or dirty. So it wasn't a big surprise to find that the convection blower wasn't dusty or dirty much at all.

    Anyway, after doing all of that, my husband reassembled that side of the stove, and re-tested, and the problem repeated itself just as you described: the stove will start the fan with the override switch, and of course it starts on "high." If we turn the knob to start the fan, and we turn the knob past "high" to say, "medium" (3) the fan won't run, there is no airflow, but the motor hums. If we then turn the fan back to 5, or "high", the fan will kick on and the airflow starts. If we then turn it down to "medium," or 3, the fan will continue to run.

    So yes, it sounds like you've echoed the problem back to me exactly as it occurs. It sounds like a new motor. We are assuming that this is a basic swap out that we can do ourselves... we have a supplier from whom we hope we can order this part. Do you think we need just the motor, or do we need the whole motor/blower assembly?
  6. stovelark

    stovelark Minister of Fire

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    HI Beca sounds like u r on top of it. One thing tho, if the convex blower turned smoothly by hand, it still could be rheostat causing issues. I suspect tho that motor is stiff turning but hi voltage (5 in your case) gets it going. I do have a question tho- You turn blower on 5 it runs, you slow it down to (continue turning the rheostat down to 3 or 2) and motor stalls completely or slows down, and continues to run at 3 or so?? If it stops and will only run strongly in the 5 or full voltage setting, then it well could be the rheostat. For the few extra dollars, I prob would replace the rheostat too, its not much more if you replace the blower. Normally the blower comes in in its housing and leads connected to it. If you get rheostat from Nap dealer, I'd expect to pay around 200-225 for blower and rheostat. Let us know how old the stove is too you said NPS40 and its the NPS45 now so its gotta be at least 2 seasons old I think the NPS45 came out in 2010 (it has digital board in lieu of rheostats for auger and blower speed) Good luck

    Stovelark
    Enviro EF3 FS pellet
    Enviro Empress FPI AC
    Enviro Kodiak 1700 FS wood
  7. becasunshine

    becasunshine Feeling the Heat

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    Hi, Stovelark!

    The stove was installed in Sept 2008. The convection fan/blower turns freely by hand. Here's what happens when it's "acting up" in a step-by-step reconstruction:

    1. We start the stove. Generally we clean our stove every day (we aren't being OCD about it; the Napoleon has a very deep, round burn pot. If the pellets have the least bit of fines in them, they will clog up the burn pot. If we have to shut down the stove to dump the burn pot, we might as well shut it down, let it cool sufficiently and vacuum it out. It's not that much trouble. So, when we start the stove, it is cold and it is clean.

    2. We usually put the feed on "high" or 5 to put enough pellets in the pot to reach the ignitor. Once the pellets are at the level of the ignitor, we turn the feed down to 4, the optimum feed setting. If there are any fines in our pellets at all, starting any 24 hour burn cycle with an overfull pot burned down to ashes has a greater chance of developing a clinker or just a lot of ash in the pot.

    3. While the initial pot of pellets is burning, and usually putting up a big initial flame in that process, we keep the convection blower "OFF" in order to let the heat exchange tubes heat up a bit. If we are near the stove, we'll just put a hand over the exchange tube outlets to see if there is heat coming out. If we happen to be standing there and there is enough heat coming out of the tube outlets, we'll turn the convection blower fan on. If we are doing something in another room, we may allow the override switch to turn the convection blower fan on. When we hear the convection blower fan turn on, we'll go over to the stove and turn the convection fan switch ON, so that when the heat dissipates and the override switch turns off, the convection fan is still running. In this particular situation, when the override switch turns the fan on, it turns the fan on HIGH. Thus, when we then turn the fan knob to ON, and we set it to 4 (our typical setting) when the override switch flips off, the fan has already started on HIGH. It will then run on 4 without incident.

    4. If, however, we decide that there is enough heat coming out of the heat exchange tube outlets, and we decide to turn the convection fan on ourselves without waiting for the override switch- this is where the problem reveals itself. If we turn the knob just on, and we do NOT turn it past its highest setting, 5, then the fan will run without incident. The knob positions are OFF, *click to on* 5, 4, 3, 2, 1. So if we turn it from OFF to *click to on* to 5, then the fan runs without a problem. If we turn the knob from OFF to *click to on* past 5 to any lower setting, the fan will NOT run. The motor hums, but the fan doesn't turn on and there is no air flow. If we then turn the fan knob back to HIGH, or 5, the motor stops humming, the motor begins to run normally, and the fan begins to run normally. We can then turn the fan control down to any setting, and the fan and the motor will respond appropriately.

    Does this make sense? This is why we were thinking that it is a rheostat problem. But, given that the stove is in its fourth season, and Napoleon stoves seem to have a tendency to lose their convection blowers/motors between their third and fifth season, would that point to a blower assembly/motor problem?
  8. stovelark

    stovelark Minister of Fire

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    Hi Beca thanks for all the info. I am now leaning toward it being a rheostat with a worn spot in the potentiometer, causing poor connection and excessive voltage drop to not start the motor. I don't think its a bad idea to have the blower and rheostat on hand, then you'll be ready for anything. I'd change the rheostat, but have the convection blower on hand, but it sounds like a weak (that will eventually fail) rheostat. I'd get the one from Napoleon too.
    Your burn pot on that stove is actually a good one, the round cast pots seem to hold up the best (the Nap, Quadrafire and Lennox Winslow all use round pot). One word about blowers, you never know how long they'll last, some one or two seasons some 10 seasons. Anyway, I think you are on top of the issues. Take care

    Stovelark
    Enviro EF3 FS pellet
    Enviro Empress FPI AC
    Enviro Kodiak 1700 FS wood
  9. becasunshine

    becasunshine Feeling the Heat

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    Stovelark, thank you again. Yes, you are right, the burn pot looks just like new after 4 years of consistent use from October/November through March/April.

    We are looking at the exploded diagram and replacement parts list in the owner's manual now. It looks like we need a W062--0021 convection blower, and a W660-0062 variable speed w/o pal nut switch, which appears to be the rheostat. Why can't they just call it THE RHEOSTAT??? =/ Anyway, based on the exploded parts diagram and the parts list, the "variable speed w/o pal nut switch," whatever that *really* means, appears to be the rheostat that controls the convection fan... ???

    Thank you for your help!
  10. stovelark

    stovelark Minister of Fire

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    You're welcome hope it fixes it for you, it should.

    Stovelark
  11. fevest

    fevest Member

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    I have the nps i40 stove and had similar problems with my fan. Had two replaced under warranty. I talked them into giving me the second one after they replaced it. The third one is running fine so far. I took the bad one to a guy that rebuilds electric motors. He fixed it for 50 dollars. He said the bearings were shot. Have it as a spare now.
  12. becasunshine

    becasunshine Feeling the Heat

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    Fevest, thank you, that is good to know. As of right this red hot moment (pardon the pun, couldn't resist :)) the convection fan itself is running well. DH put some oil in the ports when he pulled it down to clean the chamber, to make sure that wasn't the problem.

    We've isolated the problem to the rheostat, and we've ordered a new one.

    It won't surprise me if we have to replace the convection fan/motor- and if so, we'll look into getting the old one fixed as well, so we too have a spare. That's a great tip- thank you! :)
  13. becasunshine

    becasunshine Feeling the Heat

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    Just wanted to follow up: Husband took the convection blower unit off, cleaned behind it, and oiled the fan in the oil ports. The fan spun freely by hand, still made no unusual noises during operation, would function if we turned the knob/rheostat just right.

    We ordered a new rheostat, and my husband installed it today, along with a new gasket for the convection blower.

    The new rheostat as apparently solved our issue. The stove is functioning completely normally now.

    Thank y'all for your help!
  14. smwilliamson

    smwilliamson Minister of Fire

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    You have rheostat issue. No biggie. Can buy the part you need on amazon for 4 bucks. A snap to install. You should also consider replacing the igniter off switch. I suggest mounting a new switch to get the existing one out of the air path... They are plastic and melt. I'll try to post some links. Hate working from iphone
  15. becasunshine

    becasunshine Feeling the Heat

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    Hi, Scott! Thank you for you response. We had already ordered a new Napoleon rheostat from Mountain View Hearth Products. We had received it, and my husband installed it today. It has, apparently, fixed the issue. The convection blower rheostat/knob, the convection blower, and the stove are operating normally now.

    If anything else in that particular path starts to act up- thank you for your input, we'll know where to look!

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