How To Replace a Harman Combustion Blower, Exhaust Fan Draft Motor

[@voiceofreason891]

Big fan of your videos! They have saved me many hours of time and money, never mind courage, to fix my stove myself.

[@EarthSense]

Love to hear that! That's what it's all about, empowerment to the people :) Any questions let us know, we'll keep the videos coming!

[@DP-oc4bt]

Thank you so much! As a recently Single mom and my stove started making crazy racket your video saved me. I installed a new one and it’s never been this quiet❤.

[@EarthSense]

Fantastic to hear! So glad the video was helpful and your stove is up and running and quieter than ever before! If you need any other assistance down the road please let us know. Thanks!

[@sambo883]

I just changed mine out yesterday. Not bad for 10+ years. Yes, 1/8" allen screw, was way tight; soaked with penetrating oil overnight; Used small torch but still nothing. Ended up bending fan fins over and cut off at shaft. I covered the blowers in back with a rag so I wouldn't lose and hardware inside. Motor came out easy. I reused the felt gasket. New motor was a newer design with a one fan versus a two fan. The ties I had cut I left hanging so I would know where to replace with new ones. Routed power cord back and secured with new ties. Replaced damaged fan also. Not too difficult of a job to replace unless you're working on the floor like me...on your side like a pretzel. Though I did pull stove out away from wall I was able to get behind it but still awkward position. Still, u guys make it look sooo easy especially when unit is up on a lift bench...haha! Just a note: My motor was a two fan. A replacement May look different. Again, Two fan versus One fan on motor. (Hearth & Home Tech) Part# 3-21-08639 Combustion Blower / #3-20-40985 5in Single Paddle Blade. YOU Must use your Model and Serial to obtain correct part/s. Also adding: I did look up motor on parts list (online) for an Accentra-2 and brought it to Stove Shop I went to. The number I gave them was a completely different motor And $454.! Once they had serial number and proceeded checking in their system they came up with a different part # and upgraded motor. Under $200.! So, please.....either bring your original motor with you to store and/or give your serial number. Model and Serial are on back side of stove. Good Luck!

[@EarthSense]

Thanks for sharing the detailed report with the community; very appreciated. Yes, I have also seen those paddles so stuck on there that you need to bend the fins and cut it off - glad you tried the other options first. Yes, early Harman models had a combustion blower with a two blade design, later on they changed that to a one blade. Yes, over the years there are different part numbers used for the same item, it's also good to double check and cross reference. We are happy to help if needed. Thanks again!

[@robjardine2350]

Thanks for the video, just about to replace the blower on mine. Now I know what to expect.

[@EarthSense]

Thanks Rob, glad it was helpful. If you have any questions as you go through the changeout just let us know - Happy to help!

[@Rob-hv9kt]

Mine going now after 6 seasons. I noticed it becoming louder last season but now it actually stops for a second upon start up. If course we be heading into a cold spell northeast.

[@EarthSense]

Hey Rob, Just left a reply in the other message you sent. Let us know if you have any other questions. Thanks!

[@jeremythered74]

Awesome and Very helpfull video!!! Thank You Very Much! Do you happen to have a video for this, on a 1st gen harman Advance? That would be a jackpot for me.... Thank you again, Jeremy

[@EarthSense]

Glad it was helpful Jeremy! Just have the one here on the Accentra, however the Harman Advance including early models, we'll be almost the exact same for replacement on the combustion blower. Any specific questions as you dive in just let us know and we can walk you through it. Thanks!

[@richardmitchell7836]

Great video, thanks for what you do. I have a p68 and it's been purring like a kitten since 2005,but after my first ton this year and I did my deep cleaning . I have been getting smoke in the hopper and Excessive heat around the slide plate which causes the pellets to stick to the sides of hopper Creating a dam so to speak, so only the pellets from the center of hopper are being used... I was told it's probably the combustion fan but it seems to spin nicely and it's hard to get dealers around here to share their knowledge and I get that..but if you have any suggestions or clues I would greatly appreciate it and I will buy any parts from you guys from now on! Thanks again Rich

[@EarthSense]

Hey Richard, thanks for your message. I ran this past our Lead Harman Technician and here is his overview. A few things here and not typically seen on P series but not out of the question. Smoke infiltration into the hopper is an issue with any steel Harman feed system since 2004. Harman’s fix was to introduce a fresh air supply to the feed system, aka, “tube job”. 2008 this became standard equipment on all Harman feed systems through present time. Prior to 2008, this tube job had to be done as an in-field service. For the do-it yourselfer the recommended first step is to clean the creosote out of the feed system with picks and screwdrivers which requires a complete dis-assembly. The other option is to burn it out but only a trained professional should attempt this. There may be KZbin information on how to do a tube job??? Other symptoms will be diminished fuel feed to the burn pot or lower fire height. Other causes contributing could be: 1. Hopper and fines cover sealing properly? 2. Auger front flight worn away to the center post reducing the “fire-stop” capability of the auger. If the auger front flight is worn away I would certainly look at this as a first step and inspect the feed system more thoroughly once the old auger is removed. Preventing smoke from entering the hopper completely is what a tube job does. The hopper - the smoke residue or creosote can be cleaned off with stove glass cleaner, might take a bit. Once clean, apply some car wax to improve pellet flow.

[@richardmitchell7836]

@@EarthSenseThanks for the reply it's greatly appreciated! I purchased the stove in 2004 and installed myself. I noticed it didn't seem to be working as it should so I did a tube job? (aka) OAK? ..outside air kir?. It's been fine till this year..also I noticed a lot of carbon build up in the fire pot this year as well. I never had to chip the pot with a screw driver before this year. The only other variable this year was I started using softwood..which I always ran new England hardwood faithfully. I don't think that's the root problem though. Given what your saying I didn't like the way the front of the auger looked like at the beginning of the season..it does look really burnt and black and lately I have been hearing...about every 5 minutes or so a clunking noise like the auger is trying to over come something like if the pellets are to hard..lol not possible I imagine. I have 7 bags of pellets left and then it's done for the year.. well given the problem I'm having with it anyway. The fines cover does seem to be sealing good as well. I'm thinking about replacing all gaskets, doors, hopper and now fines cover along with the auger..after throughly inspection of the of all parts. As I'm typing this all I can hear is that auger clunking away..I would rather buy the parts needed from you guys after my deep dive into the stove.. as I'm assuming that you sell them??? Had to ask given what they say about assuming...lol. let me know thanks. If you have any other thoughts as well that would be awesome! Thanks again Rich. Ps. I'll be in touch 🙂

[@EarthSense]

@@richardmitchell7836 Thanks for the message Rich, always happy to assist. The 'Tube Job' is different than the Outside Air Kit (OAK). It was a factory recommendation for dealers to perform in the field prior to 2008. It's an additional tube that goes into the feed system to provide a fresh air supply. The issue you are experiencing was quite common in several of the models. I can't find any literature or videos online for this. We can add it to our queue of videos, but it may be sometime before we are able to film that. Possibly contact Harman direct and see if they have any kind of an instructional outline regarding the Feed System Tube Job. Keep us posted on that. From everything you are mentioning it certainly sounds like we have an air issue here. Generally speaking, we see creosote and hard scale build-up on the burnpot when the unit is running on low settings and we have too much air or an air leakage point. If the Hopper lid was left open or the gasket was not sealing well, it can certainly have an effect here. The pellets you burn definitely play a major factor. There are so many variances between hardwood and softwood. Good to see if the manufacturer has a PFI Label/certification on the bag (Pellet Fuels Institute) Important there's no binders or additives in the fuel. Our most popular sellers are premium softwood pellets although we do sell a good amount of premium hardwood. Good observation on the auger. My initial thought is that the creosote build-up is causing the auger to bind and clunk a bit. It will be good to do a thorough inspection of the feed system and checking the gasket seals over is always good practice after a handful of seasons. Yes, we do stock virtually every Harman part, OEM and a decent amount of aftermarket. Here is the General Page for P68 Parts for your reference. Keep us posted on everything. Thanks! pellethead.com/product-category/stove-parts-accessories/stove-parts/see-all/?model=37876

[@richardmitchell7836]

@@EarthSense wow I'm just impressed with your response.! The tube job.. im assuming is the tube in the back which I see on the newer models? I'm thinking connects the combination air to the auger Area and I appreciate you researching install of the tube job excellent. Here in CT. everyone wants to sell you a fish and not teach you how to fish...and I can kinda see and understand that as well to some point. I was on your website earlier ..just curious if the auger was a updated one given I heard some scuttle butt about a updated one and didn't know if there was any truth to that?. I'm definitely going to contact harman directly and see what information I can gather up.When I get the stove torn down and Evaluated I'll be calling you guys for parts and definitely keep you posted as well. Thanks again Rich and stay well!

[@EarthSense]

@@richardmitchell7836 Our pleasure Rich! I'm a big proponent of teaching one how to fish. Empowerment and ownership are great traits to carry in my eyes. There was a point where Harman changed the P68 auger motor. They went from a 4 RPM to a 6 RPM. 4RPM Motor Pre-Serial Number 008280309 6 RPM Motor Serial Number 008280309 & Higher The auger shaft was changed as well when Harman went to the UL Feed System. For the P68 Post Serial Number 008280309 Would use the UL Auger and Pre that serial number would use the original auger shaft. Yeah as far as the tube job goes it's been a long time for me personally since I have seen that done, but yes it is in the back and the tube connects by the auger/feed system to the combustion manifold I believe. Push comes to shove I can have one of our experienced techs provide an outline that I can send of your way on that. Look forward to hearing the progress!

[@jk3844]

Is there a video that shows the combustion motor replacement on a Harman Absolute63?

[@EarthSense]

We do not currently have a video showing replacement of the Harman TC combustion motor replacement which would include your Absolute 63. We can certainly add it to our list of videos. Harman may have a video of this on their site, we are happy to offer phone support if you need it. Thanks.

[@donnfletcher4318]

I have the XXV and have a hard time accessing this draft fan. Two wing nut and a long bolt. I loosen all 3 and the fan doesn’t budge. Seems like it sealed on. Any ideas how I can get it out? Non flammable lubricant??

[@EarthSense]

Thanks for contacting us. I believe you are referring to the fan paddle attached to the draft/exhaust motor correct? There should be a small allen bolt holding this fan paddle to the motor shaft. In may cases we need to soak that down with a lubricant like WD40. In some cases folks will use a pencil torch to heat that area up to break the fan paddle loose. There have been times that the paddle is bound to the shaft that lubricant or heat do not work. If this ends up happening, the best way will be to fold the paddle impellers in and use a dremmel tool with a cut-off wheel to cut the motor shaft for removal. Keep us posted, happy to help.

[@rubenm567]

Nice job!

[@hidaian724]

I bought a new combustion fan for mine and it came with two black wires and one green. Wondering if I got the wrong motor now. At first I thought nothing of it because I had heard rhey changed the motor since I bought it. My original combustion motor had two fans on it. But my wires don't seem to have the thermal protection either.

[@EarthSense]

Thanks for the message Randy. There are many different replacements for the combustion fan. Yes, early Harman model combustion fans had two fans, the newest replacements do not. It does not matter which wire connects to which lead except for your green ground wire. The ground wire needs to go to a ground spade, a receiving ground wire or if there is not one it can be left disconnected. The wires should be thermally protected. Many of the new wires have thermally protective plastic-type coating vs the original 'fabric-style' thermal wires. Any other questions please let us know. Thanks!

[@LPH-11]

If the flame is getting drawn down into and through the burn pot what could that be? Thanks for any help.

[@EarthSense]

Do mean the flame is coming around the edges of the burnpot? If you are consistently seeing flame shoot out the edges of the burnpot or top, we would recommend checking/replacing the burnpot gasket and burnpot flame guide. If this is not what you are referring to please provide further description. Thanks.

[@LPH-11]

@EarthSense Thanks for responding. Last summer birds made a nest in the chimney also a bird was in the fan that's behind the ash drawer going to the exhaust pipe. I didn't know all this until I tried to start it this winter. I cleaned out everything I could think of and reach. Here's what I found. First, if I do nothing it doesn't light. No ignition. It does feed and 25 minutes later it sends a 5 blink code. Second, I found If I restrict the air flow coming into the stove just by a little it will light but the flame gets drawn downward into the burn pot. That makes the exhaust pipe extremely hot. I have no idea what I should start with or why it's doing this.

[@EarthSense]

@@LPH-11 Thanks for the message back and explanation here, very helpful. Let's take a close look at the paddle impeller that is behind the ash drawer. This connects to the combustion/exhaust motor. If this impeller got bent or damaged at all from the bird it would cause improper air flow through the burnpot affecting the ignition and fire direction. Depending on the Harman model there will be differences in size and single/double blade for that fan paddle. We can steer you in the right direction if needed; just let us know your model. Very important the right one is in place for proper combustion. It will also be good for you to inspect and clean the ESP probe - we want to make sure there is no damage to the probe that took place. Quick video on cleaning that - kzbin.info/www/bejne/oaWan6F9gr6IY80si=C80osB2b5h3JXKVR Keep us posted, happy to help and get you back to 100%. Thanks.

[@LPH-11]

@EarthSense Harman p68 pellet stove. Wow! Thank you so much for your help. I think it might be easier if I make a video on KZbin and send you the link. Just so you can see exactly what it going on. I can make it tomorrow morning if you don't mind. I live outside of town and it's hard to find help or anyone to come out. I bought the house around 12 years ago and this pellet stove came with it. First time having a pellet stove. I never had an issue with it until now. I don't know much about this and I usually try to fix these things myself. I find it hard to find a detailed explanation of how and why everything works.

[@LPH-11]

@@EarthSense Here are 3 short videos explaining my issues with my Harman p68 pellet stove. Thanks! Around 3 minutes kzbin.info/www/bejne/bIOol2Csib54hZYsi=zDydlhvqtnqWhRuO Around 30 seconds kzbin.info/www/bejne/m4WslIxtbq2ricUsi=C1lwKsNxQOEHytjx Around 30 seconds kzbin.info/www/bejne/q3SchXR8lL6jeNksi=srAq1CDM5lEJ15G8

[@neilfarrar1425]

I have a Harman Iron stove. Any recommendations for finding the right exhaust fan?

[@EarthSense]

Hey Neil, Several Harman Models used the 'Iron' tag including the Accentra as you see in this video. Iron would not be the model. On the back side of the unit you will see the UL label and that should provide you the model name (I'm guessing you either have the Accentra or the Advance). As for the exhaust fan, all Harman models will use the same exhaust motor. Here is a link for reference. pellethead.com/product/harman-heatilator-ecochoice-combustion-blower-exhaust-draft-fan-motor-oem/ Any other questions please let us know. Thanks!

[@Laurie-rq3xq]

After my husband replaced our combustion fan motor, nothing else is working. When we played it in the only thing running was the combustion fan…no auger, nothing…the only light on is the combustion blower…all were working before the replacement…any ideas?

[@EarthSense]

Thanks for contacting us. Are you seeing any blinks on the status light? Any differences from Room Temp to Stove Temp? Make sure the igniter toggle is on Auto. Was the stove unplugged during the replacement? If not were there any electrical shorts that happened during installation? Double check the ESP Thermistor Probe in the exhaust and the electrical connections. Here's a video on pulling out and cleaning the ESP: kzbin.info/www/bejne/oaWan6F9gr6IY80 Check all the simple things first. Happy to help.

[@Laurie-rq3xq]

I got it running last night after watching your video about the vacuum switch! Yay! Husband cleaned the ESP Thermistor Probe, after watching your video on that. I then checked all the connections and it started up like a champ. Thank you so much for your videos! Pellet stove is in a yurt and we just got 18” of snow and temps in the 20’s!

[@EarthSense]

@@Laurie-rq3xq That's fantastic to hear Laurie! So glad you are back up and running again especially during the cold temps. If you have any questions down the road, don't hesitate to reach out! Thanks!

[@LPH-11]

Thanks!

[@EarthSense]

You're most welcome, thanks so much for your generosity! Any future questions or needs just let us know! Thanks.

[@LPH-11]

@@EarthSense 👍

[@Border-iq7we]

I have the same stove as in the video, and while taking the old blower out, one of the nuts won't come off because the stud itself is just spinning. Any suggestions?

[@EarthSense]

Thanks for contacting us. See if you can remove the other nuts and pry the motor forward a bit to put pressure on the spinning stud. If that doesn't work best option may be getting in there with a dremmel tool to cut the stud/nut. Sorry to hear this, very frustrating - hope this was helpful. Keep us posted, happy to assist.

[@Border-iq7we]

@@EarthSense Thank you for the quick reply. If I have to cut the stud/nut, are these studs replaceable?

[@EarthSense]

@@Border-iq7we Thanks for the message back. If you have to cut the nut/stud, it's going to be very difficult to replace the way that stud is machined by Harman. You could tap and die a new bolt and nut as one option, the other option would be to see if the other two nuts securely hold the motor in place. For the Harman here the bolts and nuts are just securing the motor, it's not about creating a combustion seal. So if you secure the other two nuts and the motor feels firmly in place, we should be good to go just using those two and leaving the 3rd stripped one as is. This will not affect the performance or safety of the unit, we just want to make sure the motor is secure. Hope that makes sense, please keep us posted. Thanks!

[@Border-iq7we]

@@EarthSense Perfect sense, thank you!

[@EarthSense]

@@Border-iq7we Thanks Bud, keep us posted.

[@Rob-hv9kt]

I’m wondering ,I have a question the combustion motor is a two-stage motor ??because when starting up now it stops for a second continue stops for another second then I can smell the smoke and then once it’s going it’s fine so that tells me it could be a two-stage motor which is pulling a little bit more voltage in the first stage. Or am I incorrect?

[@Rob-hv9kt]

It can’t be a 2 stage motor its only 110. So whats causing this?

[@EarthSense]

Hey Rob, thanks for contacting us. No, not a 2 stage combustion motor. On start-up cycle the program will run it near line voltage. Once start-up cycle is complete and the ESP reaches proper temp, the combustion blower will regulate voltage automatically based on your heat setting/thermostat setting. I would lean towards this being an issue with the motor given the description you provided. Often as combustion motors start to fail we will notice either noise or we'll see intermittent operation during start-up. The control board will be the only other component that controls the voltage to the combustion blower. Given all other start-up aspects are correct and it runs fine after that stall, I would not think it to be the control board issue. Hopefully that's helpful, if you have any further questions or need reference links just let us know. Thanks!

[@EarthSense]

@@Rob-hv9kt Hey Rob, just sent a reply in the previous message you sent. Thanks!

[@Rob-hv9kt]

@@EarthSense yea that makes sense also i did notice last season combustion motor a touch louder. Thx!!

[@EarthSense]

@@Rob-hv9kt Most welcome Rob, yeah I would be near certain that is our issue here. Keep us posted! Thanks!

[@mikechurch485]

I have the identical harmon stove as in your video, recently it seems the combustion fan runs continuously after temperature has been reached and stove hasn't burned any pellets for hours. Is this normal?

[@EarthSense]

Hey Mike, thanks for the message. The combustion fan will come on as soon as you start up the stove and it's calling for heat whether you are on Room Temp or Stove Temp mode. The Exhaust ESP Thermistor probe regulates the combustion fan during operation. When you shut the stove down or if it runs out of pellets, the ESP probe is the device that tells the Combustion fan to shut down when everything is cool. If your fan continues to run when the unit is cool, we suggest you check that ESP and give it a good cleaning. Here is a video that will show you that process. Keep us posted, happy to help. kzbin.info/www/bejne/oaWan6F9gr6IY80

[@mikechurch485]

Thank you

[@mikechurch485]

I cleaned the probe, but think something still isn't right. I turn the temperature setting to around 60 degrees which should keep the pellets from loading into burn pot right? For some reason the stove keeps moving pellets, any help would be appreciative

[@EarthSense]

@@mikechurch485 Hey Mike, thanks for the message. Sounds like you are running on Room Temp Mode which relies on the room sensing probe that plugs into the rear of the unit. Play with the positioning of that probe and see if it has the same effect. Example: If that probe is on a cold floor or by a cold draft area that was under 60 degrees, it would certainly cause the stove to start up and feed pellets. When you operate on Stove Temp mode and shut the unit down or it runs out of fuel, does the combustion fan continue to run for more than 90 minutes? If running on Stove Temp mode and you turn the dial to off, does it continue to try and feed pellets for an extended period of time? Just want to narrow this down, we could very well need to replace the Room Sensing Probe and/or ESP probe here, just want to try and isolate the situation before you start looking at replacement parts. Are you still having the issue with the combustion fan running for hours on a cold stove as you originally reported?

[@mikechurch485]

Thanks for the prompt response, I will try your suggestions and let you know. We have potentially a big snowstorm on the way so the stove might be running a little more than it has these last few weeks. I will post another comment when I'm able to use your suggestions

[@milagrossmith4891]

Do you have a video of this teaching on a Harman Advance?

[@EarthSense]

Thanks for the message. We do not, just on the Accentra FS here, however the Advance is very similar in all aspects. Any specific questions let us know, happy to guide you through. Thanks!

[@milagrossmith4891]

@@EarthSense Ok. Also I went on your webiste to try and purchase the auger and combustion motors but I do not know which I need because you have several to choose from. My advance is from 1999 so do I need the counter or counter-clockwise auger and which combustion motor would I need?

[@EarthSense]

@@milagrossmith4891 Thanks for the message. 1999 Advance will have the chain driven feed system which requires the 4RPM Counter Clockwise Auger Motor. Link below will show you OEM and Aftermarket options. We also have a video on auger motor replacement in the chain drive Advance if you need to reference that. kzbin.info/www/bejne/d5bYlp6GfcmiedU pellethead.com/product/harman-4-rpm-counter-clockwise-auger-feed-motor-oem/ The combustion motor will be part 3-21-08639 and fits all year Advance models. Link here will show the OEM and aftermarket options. pellethead.com/product/harman-heatilator-ecochoice-combustion-blower-exhaust-draft-fan-motor-oem/ Let us know if you have any other questions. Thanks!

[@milagrossmith4891]

@@EarthSense I am in the process of ordering now. Does a combustion motor come with the single paddle blade or do I have to purchase have separately

[@EarthSense]

@@milagrossmith4891 Your Advance uses the 5" double paddle fan blade. If you do need a new paddle that will be separate - here is the link to the one you would need pellethead.com/product/harman-heatilator-5-double-paddle-combustion-fan-blade-impeller-aftermarket/

[@va3dxv]

@2:30 "...and that impeller wheel will come right off there like that" HAHAHA sure it will! If your stove is nice and new like that one is... but then you probably don't need to replace it. Thanks for the overview, but this isn't exactly a real world scenario :)

[@EarthSense]

Thanks for the message. As mentioned in the video from 1:30-2:00 sometimes that paddle can be very stuck on there depending on age/use and we recommend soaking it down with lubricant such as WD40 for an extended period of time. From there if it still will not budge, in most cases if heated with a pencil torch the metal will expand and it can be broken loose. Only in a small amount of situations have we seen where that paddle impeller needs to be cut-off to remove. Thanks again for your comment, appreciated. Any questions down the road just let us know!