# Need advice on buying an older Harman stove



## Tim_M (Mar 28, 2010)

I'm thinking of buying an older (mid-90's) Harman pellet stove that needs an auger motor. The seller doesn't know the model. He is asking $150, including some pipe. I'm wondering if it's too old to bother with, or would it be worth buying and trying to repair? It would be my first pellet stove (I have burnt wood for 20 years), but I've been doing some research and Harman seems to be a respected manufacturer. In general, are pellet stoves from the mid-90's inferior to more current ones? I'm attaching a pic in case anyone recognizes this particular model. Thanks for any suggestions you may have.


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## imacman (Mar 28, 2010)

I'm no Harman expert, but I believe it's either an Invincible T or RS.

http://hearthnhome.com/downloads/serviceParts/Invincible_T.PDF

http://hearthnhome.com/downloads/serviceParts/Invincible_RS.PDF

Ask the seller to look for the rating plate.....it may be inside the hopper or inside the side panels.....that plate will have the model information.

For $150, it's worth a shot, IMO.  Harman lists both auger motors as "in stock".


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## dperk (Mar 28, 2010)

All my Harmans have been rock solid.  Don't know this particular model, but I am very happy with Harman.  Good Luck.


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## MSmith66 (Mar 29, 2010)

Old but, still a very good model. Lucky for you $150. is very cheap.  You can still get parts from almost ALL dealers. One thing to look out for is cleaning, when you take off the side panels, there are angle iron pieces on each side that you need to take off and clean. The manual may not tell you this.   You will have to brush these areas out with a long wire brush ( that came with the stove) that you can purchase from a dealer.  That is a keeper. Have fun.


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## Snowy Rivers (Mar 29, 2010)

A general rule of thumb that I use is this.

If the cabinet and major structure of the stove is in good condition 
Fire pot and internal areas that is exposed to fire is not corroded or damaged from high heat
Look over the heat exchanger tubes and (IF YOU CAN) be sure they are in good order.

ASk to plug the stove in and see if the exhaust fan and room air blowers run.

An auger motor is a cheap fix.

Even if you need to replace a control board and a few other items, the stove should definately be considered a good buy at $150.

I bought both of our Whitfields for $200 each.

If you buy this stove.

Get it outside and take it apart as far as you can to gain access to clean it and check it over.

Blow out everything real well with compressed air to remove dust and dirt that has accumulated over time.

Use some good cleaner like 409 and a rag to wipe down everything in the mechanical cabinet.

Remove all the fans and carefully blow out the squirrel cage wheels to get all the dirt off the fins.

Make sure that there is not any crap left on even one fin as this will cause an out of ballance condition and the thing will vibrate.

A small (1/2") paint brush can be used to gently brush the fins on the fans off, then blow out.

Clean out the exhaust fan blades real well and then make sure all the ash traps are spotless.

Lube the motors if they have places for oil.

Many draft fans will have two oil holes.

 Most room air fans have non serviceable bearings and should be fine unless they are noisy.

Check the wiring for any spots that could have frayed or ??? due to rubbing on things.



Be sure all the gaskets are in good order.

Once you have the mechanical stuff all done, give it a test burn outside and make sure it works right.

I like to do at least a 1 hour run  to make sure things are in good order.

Give the stove a paint job before taking it inside.

Should be as good as a new one at a fraction of the cost.

My opinion of the older stoves is that they are in some ways better. LESS electronics to go south.

You can likely find an owners/service manual online maybe at a slight cost. (great to have)

OH BTW if you can snag the little hearth pad with the $150 purchase, so much the better.

(Booty ya know)

Good luck and have fun.

Snowy


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## Defiant (Mar 29, 2010)

I concur with Snowy, that is an Invincible, very heavy but well worth the $150.


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## Tim_M (Mar 29, 2010)

Thanks Snowy, for the very detailed post, and everyone else for your comments. I am going to go look at the stove this weekend (it is an hour's drive away). If I plug it in and the blowers work, is that an indication that the the control board is OK, or could there still be problems with it? Any idea what a new board would cost? Also, is it fairly easy to remove the door? I'm thinking that if I buy it, removing the door may make it easier to lift in and out of my van. Thanks again for all the help.


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## rap69ri (Mar 29, 2010)

The board cost depends on which model Invincible it is. If it's the T series the boards are about $350, if it's the RS the board is about $150. The RS has the all digital board, and the T has a manual knob for adjusting the pellet feed rate. I've worked on both, and prefer the RS but would take the T without hesitation.

Bring a couple of friends with you to pick it up. That stove weighs about 415lbs, and is very awkward to lift.


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## Snowy Rivers (Mar 29, 2010)

If the fans start up, thats a good sign, but until the feed motor is working, there is no really good way to tell for sure.

Remove everything you can take off easily to lighten the beast up.

I am not familiar with that stove but cast stove tend to be very heavy.

Take the door and anything else off that you can.

If the feed motor quit, it did so for one of a couple reasons probably.

Motor got tired and died or possibly there was a control issue.

Now there is always the possibility that the feed motor is fine but instead a safety has failed.

The pressure switch or other device could be keeping the stove from running.

This can be checked quickly with a VOM and just test the switch to make sure its working properly.

Some stoves use a negative pressure pots and the vacuum switch senses this.
If the switch does not sense vacuum it can be due to a failed exhaust fan. plugged ash traps or ???  even a plugged vacuum hose

Other types can include a switch that senses a blocked flue and will close in such a case..


Again. Have fun with the new stove and keep us posted.


Snowy


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## Snowy Rivers (Mar 31, 2010)

How is the deal coming ????

Currious

Snowy


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## Tim_M (Mar 31, 2010)

I'm hoping to go and have a look this weekend. Unfortunately I learned that it's a bit further than I first thought, about a 2 hour drive to the middle of nowhere. Which is probably why he hasn't sold it yet, after 2 weeks of being advertised.


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## Tim_M (Apr 13, 2010)

Well I bought the stove, for $125 incl the hearth, and managed to get it home last weekend - no small feat considering the weight. It's an Invincible T built in 1992. Anyway, both blowers work when I plug it in, a good sign. I have started the task of taking it apart and cleaning it - it looks like it hasn't been cleaned in years. One thing I'm a bit concerned about is that there seems to be some corrosion on the surfaces of the burn pot, baffles, etc. Not sure if that's going to effect performance or not. 

I noticed right away is that the ESP probe was unplugged, so I'm hoping that's why the feed motor wasn't working. But it could be that the previous owner unplugged it when trying to diagnose the problem, or it came unplugged when I was moving it. I took the probe out and it is a bit black, but not as bad as I expected. What's the best way to clean it?

I downloaded a manual, and it says that the feed motor won't come on until the exhaust temp reaches 165 degrees F (as detected by the ESP). So is there a way I can test the motor without actually burning a fire? 

I can't seem to find any place to lube the blower motors, even though the manual suggests it.

Also, I'm wondering if I should try to remove the burn pot for cleaning? There are 4 bolts but they're not so easy to get at, and I assume there's a gasket that I'll need to replace if I take it off. The manual doen't mention this at all in the maintenance section. Any thoughts on this?

Sorry for all the questions, but any suggestions would be appreciated.


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## MSmith66 (Apr 14, 2010)

Tim - Check your PM.


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## Lousyweather (Apr 14, 2010)

Tim_M said:
			
		

> Well I bought the stove, for $125 incl the hearth, and managed to get it home last weekend - no small feat considering the weight. It's an Invincible T built in 1992. Anyway, both blowers work when I plug it in, a good sign. I have started the task of taking it apart and cleaning it - it looks like it hasn't been cleaned in years. One thing I'm a bit concerned about is that there seems to be some corrosion on the surfaces of the burn pot, baffles, etc. Not sure if that's going to effect performance or not.
> 
> I noticed right away is that the ESP probe was unplugged, so I'm hoping that's why the feed motor wasn't working. But it could be that the previous owner unplugged it when trying to diagnose the problem, or it came unplugged when I was moving it. I took the probe out and it is a bit black, but not as bad as I expected. What's the best way to clean it?
> 
> ...



you can test the motors by simply making a pigtail and plugging them into line voltage from the wall (basically cut a extension or lampcord, strip the leads, crimp on a couple alligator clips, and away you go....oh, and dont touch the alligator clips together...careful here)


There is no place to lube the motors.

Dont remove the burnpot, but, if you HAVE to, youll need two gaskets, one for inside, one for outside.

The feed motor you can also text with your aformentioned pigtail. A few reasons this might not be running though. All doors need to be closed, the vac line should be checked, as well as the vac switch.


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## Tim_M (Apr 15, 2010)

Thanks, Lousyweather, I think I'll try to test the feed motor this weekend using the method you described. I can't seem to find anything that looks like a vacuum line or switch. Where would they be?

On the burn pot, I noticed that when I insert my finger into the ash clean-out hole on the underside, there seems to be quite a bit of caked ash stuck inside. I tried bending a stiff wire and pushing it up into the hole to loosen this material but I don't think I'm getting much of it. I'm worried it may obstruct air flow to the small holes near the front edge of the burn pot. Any tips on how to remove this caked ash, short of removing the burn pot?

When I removed the stove's side panels I noticed there are small metal flaps, one on each side to the front and about 1/3 of the way up the side. Would these be for fresh air intake? Inserting my finger, they seem to be quite dirty inside as well so I think I'll remove the flap to get at the inside area.


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## imacman (Apr 15, 2010)

My advice would be to take the stove COMPLETELY apart.  I'm sure that it needs a thorough, complete cleaning of the entire thing.  Take notes of anything you disassemble so you know what goes where, order of assembly, how it goes back together, etc.   Don't just clean piecemeal.


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## smalltown (Apr 16, 2010)

macman I like to take photos with a digital camera as I disassemble something. Really helpful to be able to look at parts and their orientation,and relation to other things if you get stuck reassembling.


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## imacman (Apr 16, 2010)

smalltown said:
			
		

> macman I like to take photos with a digital camera as I disassemble something. Really helpful to be able to look at parts and their orientation,and relation to other things if you get stuck reassembling.



Great idea too!


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## Tim_M (Apr 17, 2010)

Thanks for the tips. I have started disassembling things, and ordered some gaskets today from a local Harman dealer. And I think I'll follow the advice about taking some pictures as I go along. After reading some of the different posts on this forum, I'm wondering if I should also order a new ESP probe, just to be sure I have that is working 100%. Any idea what that would cost?


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## smwilliamson (Apr 17, 2010)

That is an awesome stove. I have the insert model. I see these fetch 1600 used all day long. If you don't want it after you get it, PM me and I'll give you $200 for it.


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## smwilliamson (Apr 17, 2010)

imacman said:
			
		

> I'm no Harman expert, but I believe it's either an Invincible T or RS.
> 
> http://hearthnhome.com/downloads/serviceParts/Invincible_T.PDF
> 
> ...



Auger motor: 1NFL4, $89.90 from Grainger...same exact OEM motor private labeled for Grainger...that product # is from memory, double check, its the 4rpm gear motor listed.


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## smwilliamson (Apr 17, 2010)

Auger motor: p.93 in the Grainger catalog, part # 1LNF7, $89.90


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## Tim_M (Apr 18, 2010)

smwilliamson said:
			
		

> That is an awesome stove. I have the insert model. I see these fetch 1600 used all day long. If you don't want it after you get it, PM me and I'll give you $200 for it.



Thanks but I think I'm going to keep it. But it's good to know I bought a model with a good reputation, and for a great price. And thanks for the info on the auger motor, but I think mine is OK because I tested it using the method suggested by Lousyweather and it seems to work. So now I have to finish my cleaning, get it back together and try a burn test. I'm hoping the reason it stopped working for the seller was because the ESP was unplugged. Otherwise it could be the ESP or the board are bad.


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## smwilliamson (Apr 18, 2010)

Clean off the esp probe really good. When you get it set up let us know.


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## smwilliamson (Apr 18, 2010)

ESP probes are $15 bucks??? I forget what I paid the last time.

I bet you the auger motor is not working because the fines catch box is so full that the slide plate is restricted. Test the leads going to the motor for power. I would also take the auger out and inspect the feed canal for any gumming. DO NOT TAKE THE FOUR BOLTS OFF THAT HOLD THE BURN POT ON I'VE SEEN A LOT OF PEOPLE SHEAR OFF ONE OF THOSE THREADED POSTS TRYING TO LOOSEN THE BOLT. THERE IS NO NEED TO REMOVE IT. YOU CAN ACCESS THE FEED CANAL FROM THE REAR AFTER THE AUGER COMES OUT.


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## Tim_M (Apr 20, 2010)

I just tried a test burn, and things didn't work out too well. The blowers seemed to work fine, but the feed motor would only run for a few seconds at a time. It seemed to start up randomly, every 3 or 4 minutes and run for maybe 3 or 4 seconds before stopping. It began doing this immediately after pressing the start button, before I even lit the pellets in the burn pot. Also, when I pressed the shut down button, the blowers stopped immediately, with no cool down period (could be because the stove never did get to operating temp?) So I'm guessing the ESP probe needs to be replaced, or there's a problem with the board. Any thoughts?


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## smwilliamson (Apr 20, 2010)

Pressing buttons? I do not have buttons on mine. I have control dials. Hmmm. I'll dig into it and get back to you.


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## lmjr (Apr 21, 2010)

Tim_M said:
			
		

> I just tried a test burn, and things didn't work out too well. The blowers seemed to work fine, but the feed motor would only run for a few seconds at a time. It seemed to start up randomly, every 3 or 4 minutes and run for maybe 3 or 4 seconds before stopping. It began doing this immediately after pressing the start button, before I even lit the pellets in the burn pot. Also, when I pressed the shut down button, the blowers stopped immediately, with no cool down period (could be because the stove never did get to operating temp?) So I'm guessing the ESP probe needs to be replaced, or there's a problem with the board. Any thoughts?



Auger gearbox could have a bad cog or two...look to see if motor still spins while auger doesn't turn.

If you have access to VOM or DMM (Volt-Ohm-Meter or Digital Multi Meter) you could watch voltage at auger motor.

That would tell you when it's on and if it is at full voltage...shows when and what control boards is sending to the motor.


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## Tim_M (Apr 21, 2010)

I'm pretty sure the motor isn't spinning at all, except during those short intervals, so I don't think it would be the gears. Also, I previously tested it using the method suggested in one of the earlier posts above, by connecting power directly to the motor, and it seemed to work fine. One reason I'm thinking the ESP could be at fault is that the prongs on the end of the ESP that the wire plug connects to are slightly bent.


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## Lousyweather (Apr 21, 2010)

Control Board likely, ESP maybe.


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