Enviro M55 convection blower issues/questions

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MattCorrow

New Member
Jan 28, 2022
29
Shaftsbury, VT
We have an Enviro M55 that we installed a couple of years ago, and it looks like the convection motor is failing.

It'll start out working beautifully, then start to vary the speed after "a bit", then stop running altogether. I thought it might be the low temperature sensor, pulled that out and tested it(no issue).. When I looked at the convection blower, the motor part was very hot, although it didn't seem to be having any issue spinning..

I know several of you have had a failure with this motor, so I'm hoping someone has some helpful hints on how to make it last longer..

Since the manufacturer's warranty is only 1 or 2 years, and the motor itself is $200 or more, and the service call is going to cost me $200 itself, it's not a part that I want to have to replace every couple of years.. If there is anything I can do for maintenance, I'd be happy to....(do they need to be oiled?)

I also saw one post that mentioned that most pellet stoves are not being used as intended? Kind of made me a little confused...

In my case, once a week I am doing a full cleaning (not just the tray).. I do however, run it for about 18 hours a day... Not sure if that what's not intended?

Any helpful hints would be greatly appreciated.

Thanks!
 
If the fan runs, slows down then stops (Very Hot) time to replace
I run my enviro 24/7 about 7 months of the year
keep it clean feed it good pellets and it will be happy
 
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There really isn't a lot you can do to prolong the life. Replacing the blower is really not that hard if you have basic tools around. I've replaced mine several times (and getting ready to do it again). I run my M55 almost constantly from end of October until May, stopping only to clean. It seems the fans have a lifespan of about 2-3 seasons before they start getting noisy and in one case- the bearing literally fell out leaving the fan to make a loud metal/metal sound as the squirrel cage fell down and went round and round. Boy that was fun at 3a.m.

That being said- there is a tutorial someone posted about replacing the sealed bearings in the fan- that's usually the cause of the failure. The bearings just give out- they are sealed and you can't lubricate them. I have the parts to try it, and I am going to do that when I remove this noisy blower and replace it with a new one. Hopefully the rebuild will work and I won't have to purchase a new fan again. I'll just have two blower assemblies on hand and just rebuild them.
 
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Unfortunately it does sound like the blower is going bad. They certainly last longer usually but things happen. As has been said, it’s not too hard to replace with basic tools if you’re so inclined.

the Enviro stoves are well built And it should be no problem running it 24/7 as long as it’s cleaned and maintained properly. As another point of reference, my M55 insert is 15 years old and it has had no problem running 24/7 when the weather is cold (as it has been this year). I’m pretty sure both the combustion and convection blowers are original in my stove and they’re still quiet.

Ken
 
Well Ken count yourself lucky. My convection blower has faithfully given up the ghost almost every 2-3 years. I have my M-55 10 years. That is, in my opinion, excessive.
 
I agree with you. So now I’m wondering when mine will go. Have you tried different brands of fans or is there possibly anything that may have contributed? I was *given* my M55 insert last year so I don’t know how much it was used before that, but considering the erosion in the burn pot it must have been a fair amount. I run it pretty heavily during the cold weather but for less extreme weather I’m using a StCroix Hastings. I run *that* stove 24/7 (with a Thermostat) during the heating season. It’s not as big as the M55 but it chugs away no problem. I replaced both fans in it last year because they were physically getting worn out.

Ken
 
Thanks for all the helpful info! I called the dealer that installed our M55, and they had a new fan in stock... ($279)..
I installed it (not difficult at all), and it is working beautifully now... After spending $295(after tax), I'm going to see if I can figure out how to oil the old one.. I've ordered a bottle of Tri-flow oil (with teflon in it), in case I can use that.
Thanks for the info about sealed bearings.. If you can locate the info about replacement bearings, I'd love to try to locate some myself..
Before the fan would heat up, we were hearing a metallic noise like "tinsel" intermittently... I wonder if that might have been wear in the bearings....
After reading these posts, I'm not optimistic about being able to oil what I have, but the replacement of the bearings should be possible...
I actually wouldn't mind replacing the bearings with non-sealed ones...After all, it's really easy to grease a bearing with a good heat resistant grease...(if you're going to have to pull the fan anyway...

In my case, we have a 3400 sqft house, 250 years old, with most of the house not able to be insulated.. A couple of years ago, we replaced the furnace with a 4 zone hot air oil system, and over-insulated the duct work.. Although we can't heat the entire house with the M55, we can at least keep the temperature pretty constant (when it is -5 degrees outside)... Since we have a new furnace, and 4 zones, the cost of pellets is not drastically below the cost of oil, so having to shell out several hundred dollars a year in maintenance on the M55 makes it almost not worth doing(except for the "green" aspect of using pellets)...

Thanks all, I'll try to post info as I rebuild the old blower..
 
I took the unit apart (kind of).. The bearing on the end I could hear a little "something" when I spun it... I'll guess that is "dry"... Yes, oiling may not help, but it's certainly worth a try..(once I get the tri-flow oil) I could not see any way to get to the bearing in the motor, not sure if that one is an issue.. Since the motor is 115v AC, I can certainly rig up a plug for it, remove the cage and plug it in for a while to see if it heats up... It certainly would be great if all I had to do was install a new bearing on the end. I can't imagine that a new bearing would be more than $20.(of course, figuring out how to get the bearing off the shaft will be fun)...

I tried to look up the model number of the motor, to see if I could find a replacement
it's an ebmpapst M2E068-BF79-33.. Not sure if that's the same one they use on everyone else's fan....No luck whatsoever in finding any info.
The company(ebmpapst-Germany) makes a lot of different motors..

Thanks! Hope any info helps.
 
Seems to me I have 2 down in the basement,with noisy brgs, never got around to see if it is feasible to repair them. Perhaps will grab one later and take a look. BTY, most motors that use ball bearings don't use oil they use a light hi temp grease. Oil will leak out. But, if easily accessible, oil is easier a time or 2 a year.
 
next time I have the unit apart, I'll measure the bearing, see if I can determine what the replacement ought to be.. I'll have to locate my bearing puller, see if its small enough to be used for this..
 
If its the same as other stove convection squirrel motors you can get it off just be careful to not break the plastic on the impellers. I lightly used a long prybar to get mine off and some pb blaster.

I haven't replaced the bearings yet as they are interference fit and the ones I ordered the id was slightly larger.
 
... My convection blower has faithfully given up the ghost almost every 2-3 years. I have my M-55 10 years. That is, in my opinion, excessive.
My experience has been the similar.

My first blower went out 6 or 7 years ago so I replaced it with a new blower. I put new bearings in the original and put it on the shelf. Then about 3 years ago it started squealing again so I replaced it with the one on the shelf that had new bearings. I suspect I'll be playing this swapping game for the life of the stove.

Marc
 
My experience has been the similar.

My first blower went out 6 or 7 years ago so I replaced it with a new blower. I put new bearings in the original and put it on the shelf. Then about 3 years ago it started squealing again so I replaced it with the one on the shelf that had new bearings. I suspect I'll be playing this swapping game for the life of the stove.

Marc
Get the highest quality bearings you can, not skateboard bearings. Just saw a deal on some on the bay, other day.
 
On ebay. SKF. QE6, which is old term for "electric motor duty bearings", they use a new designation now.
Search for-

10 SKF 608 2Z QE6 bearing, made in Italy.​

 
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I totally agree. Good quality bearings will not fail in a year or two of intermittent use. I looked up SKFs MTBF ratings for an appropriate replacement bearing and at 100c, running continuously at 2000 rpms they have a greater than 200000 hr MTBF rating. And in my work, those kinds of numbers are completely normal. Some no name junk bearings are cheaper, but they won’t hold up.

Ken
 
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OK.. Although I have not tested the motor yet, I'm ordering a new bearing..
The bearing is 8x22x7 (8mm shaft diameter, 22mm outside diameter, 7mm width).. Turns out these are skateboard bearings (who would have known).. I am ordering a set of two shielded(greasable) on amazon for $4.... I saw some made of carbon steel, but apparently carbon steel rusts very easily.... I'm not sure if one particular type of bearing would be better for a fan that is going to be running constantly..

HTH
 
OK.. Although I have not tested the motor yet, I'm ordering a new bearing..
The bearing is 8x22x7 (8mm shaft diameter, 22mm outside diameter, 7mm width).. Turns out these are skateboard bearings (who would have known).. I am ordering a set of two shielded(greasable) on amazon for $4.... I saw some made of carbon steel, but apparently carbon steel rusts very easily.... I'm not sure if one particular type of bearing would be better for a fan that is going to be running constantly..

HTH
Reread this thread. Skateboard bearings are junk.
 
Yeah there is a noticeable price difference, I’ve replaced bearings with cheap ones and found out the hard way, I have 2 combustion blowers that I have replaced with ones from motion that are still holding strong years later