Harman Advance problems!

[timjk69]

I bought a Harman Advance last fall. I installed with the help of a friend in the buisness. We did the draft checks and adjusted. Draft is on the high side, 18' of 4" pipe. It ran great other than a noisy/vibrating auger motor that was replaced, no problems.
This heating season I had found a "dead spot" in the temp dial at about 74 deg. where the stove would just shut down into idle mode. This dead spot has increased in range overtime. Sometimes I can just tap the end of the knob and the stove will take off and heat, sometimes not, sometimes for a little while.
It seems like to me a no brainer that the temp. pot has a problem. My dealer is at a loss. I carefully suggested my theory. The dealer contacted the factory and they told me to clean the stove, clean the exh. temp probe, and move the room sensor farther away, so I did.
Suprise! Same problem, but last night I noticed the dist. blower "hunting" in low fire mode. Up down, in between, several times in a few minutes like it can't decide where it wants to be, very irritating. I moved the temp dial down just a hair and it settled down to a steady speed. My wife complained of this problem in the past, but I blew her off.
I'm getting a little nervous as the heating season is ending and my 3 year warranty will end this fall.
Geez! Why didn't I get a Crossfire like my a freind suggested
Any help?

 

[GVA]

Not sure but if your turn the room temp knob to stove temp while you are in the dead spot does it still sit idle? If yes I'd say get the board replaced.
Did the dealer connect the dmm to it to see what was going on with the sensors?

 

[timjk69]

If I go to stove temp, the heat output will increase. No the dealer did not use a dmm. My dealer seems to be a little new at all this. He said he was going to contact Harman again and see if they could help.

 

[GVA]

The dealer really needs to hook up to the stove and see what the room temp sensor and the exhaust sensor probe is seeing in relation to the temp knob and not be guessing.....like me......

 

[HarryBack]

yeesh....have the dealer replace the board! You cant replace the pot, and its under warrantee! Its an easy fix too.....I can replace that board in less than a few minutes. We've seen the post go bad as well....it happens. Unbeleivable.

 

[timjk69]

Latest update on my Harman Advance problem. Haven't been using the stove everyday, but still the same problem. The dealer says sure looks like a circuit board malfunction. He says no problem, we'll just get you a new one.
He calls the factory, says hey, send me out a new circuit board. Whoever he's been talking to says they don't go bad, let's try moving the sensor closer to the stove now and I do. If that doesn't work we'll try someting else. Dealer explains to the factory that the stove worked well for one season and all that. They still don't want to send out a board. Dealer seems as frustrated as me now.
So what's that all about, you dealers out there???
How do I get a new circuit board sent out? It looks like I could replace it myself in a few minutes, I really hate calling up the dealer and bugging him.

 

[HarryBack]

KEEP BUGGING THE DEALER!

Has the dealer come out and stuck the DDM on the stove yet? Most dealers should have one. It takes, oh, all of 30 seconds to hook it up and page thru the readings.....if there is an inconsistent reading on either the exhaust or room temp probe, then it should be replaced...very easy to do, but youd want to be sure thats the issue. If both of those are good, or read good on the DDM, then its time to replace the circuitboard. This is what completely baffles me in this case. I agree, it sounds like a potentiometer problem on the circuitboard.....How warrantee works with Harman, as far as I know, and I do alot of it, is the dealer comes out, the dealer diagnoses the problem, the dealer replaces the broken part, THEN submits a form to Harman for an RMA for the broken part, plus the labor they allow to fix it. The RMA gets approved, and its almost ALWAYS approved (ive never had one refused), faxed back to the dealer, and the dealer sends the broken part back to Harman. WHen they get the part, the dealer is credited back. I dont really understand this folderall about getting a part. Dealers dont stock replacement circuitboards? BS. That same board goes in the Accentra, the Accentra Insert, the P68, the P61A, and the XXV. There are pencil switch settings to identify the particular stove to the board located on the board. Some dealers cannibalize their floor models for the board and replace it when they get a new one, some keep spare boards. My point is, that boards can, and do, go bad, and I find it quite odd that the dealer doesnt have one either in an existing unit, or as a spare. I keep somewhere around 5-8 spares at any one time. Middle of winter, stove breaks, its cold, and youve got to try to explain to the owner youve got to wait for the board? Seems pretty foolhardy.

Harman Part # 3-20-05374 . If you have to buy one from some dealer and fight over getting reimbursed by Harman or your dealer, it should cost you around $169.99 + shipping from any reputable dealer. ;-) Problem is here, that unless you can get another dealerto come out and fix it, its the original selling dealer who has to submit the warrantee claim. In other words, if said reputable dealer shipped you a part, it would have to be paid for, by you, and youd have to hammer on the dealer or Harman for reimbursement. As for changing out the board.......quite easy....3 plug connections, a couple screws....

Keep us posted.

 

[Gooserider]

Not a pellethead, and wouldn't know a Harman unless I tripped over it's (IMHO poor) warrantee, so take this for what it's worth. The symptom you describe screams bad pot to me as a electronics tech type person. If you can get access to the pot terminals, and feel reasonably comfortable with a meter, this is something that you can check yourself in just a few moments...

Basic Potentiometer tech explanation - A pot works by having a constant resistor with a "wiper contact" that rides across it. The constant resistor has a uniform change in resistance across it's length. A pot normally will have three terminals, one on each end of the fixed resistor, and one on the wiper. The resistance between the fixed terminals should NEVER change. The wiper will divide the fixed resistance value depending on it's position. IE if you have a pot with three terminals "A, B, C" where A and C are the fixed resister ends and B is the wiper, the value for A-C will never change, and the sum of A-B and C-B will equal A-C. If there gets to be crud on a spot in the wiper's travel, you will get "dead spots" because the wiper is not making proper contact with the fixed resister.

Note, occasionally you may see multiple pots mounted on the same shaft (i.e. some stereo equipment controls) or combined with other switches (i.e the on/off/volume knobs on many radios) but the basic function is still the same.

To test...

1. WITH POWER OFF (make sure this includes any backup batteries that may be in the board) figure out which pot terminal is the "wiper". Usually it's the middle one, but not always, many pots will have this printed on them schematically. At worst repeat this test with each of the three possible combinations of terminals - One won't change, the other two should change in opposite directions from each other.

2. Connect the meter across the wiper and either end terminal. Set the meter to an OHM scale appropriate for the pot, you want to be as close to full scale as practical.

3. While watching meter, SLOWLY turn the pot from one end to the other. You should observe a smooth progressive change in the readings as you move the pot. The change might not be "linear" as some pots use a logarithmic or "audio taper" resistance change, but it should be a smooth change with NO spikes, or "dead" spots where the wiper reads open. If the change is anything but smooth, or you find spots that read open circuit or high resistance then the pot is bad. It needs to be changed, or whatever it's a part of does.

Hope this helps,

Gooserider

 

[HarryBack]

sure, goose, but why wouldnt this be done by the dealer if the stove is still under warrantee? Besides, the circuitbard is easily replaceable. I can replace it long before the pot gets checked...really quite easy. This issue he describes certainly isnt "the norm" and begs to be looked at by the dealer, and rectified. Somethigns wrong, (yea, most likely the pot), and needs to be changed. Why monkey around with it? If the potentiometer is bad, replace the board. Then its over and done with.

1. Use the DDM to check the probes (room temp, and ESP probe...especially he ESP), if they test ok:
2. Run the DIstribution fan in test mode........does it work ok?...then...
3. replace the circuitboard

 

[Gooserider]

As I mentioned Harry, I know nothing about Harmans and how to test them specifically - I saw a description that screamed "bad pot" at me, both the "dead spot" and that tapping on the shaft end sometimes helped. So I gave the process for testing a pot, which applies to pretty much ANY device that has a pot in it.

I agree 100% that if the unit is still under warrantee the dealer (or Harman) should be taking care of it, but it sounds like the OP is getting his chain yanked by someone and isn't getting properly serviced. I won't speculate on whether this might be to "run out the clock" on his warrantee, or a lack of competence, or a bad description of the symptoms by the OP, or what, but there seems to be a problem.

My idea is to give the OP a test process that would allow him to call the dealer and in effect say "I've tested the board, and confirmed that it has a bad pot that shows this precisely described failure mode - now cut the chit and bring out the proper replacement part!" Your test process gets to the same point, but is more a process of elimination that leaves more wiggle room to say "well maybe it's .... so lets try....." If I were a Harman tech, I'd likely try your approach by preference, but for whatever reason either they aren't using that procedure, or there is a different issue.

Gooserider

 

[HarryBack]

Ive no idea eaither, Goose. Should really be a no-brainer. Regardless of what method he uses, its likely the board. The pot isnt dealer-replaceable. Anytime we've seen issues like this, basically just like you said, its a bad pot. Theres really no need to overanalyze the issue...replace the board, be done with it. Harman requires the dealerto do the change. I just cant understand why he wont or cant. Its literally a 5 minute change, if that. the dealer wont be "out" the part, as they get credit for the bad one anyways.
Your testing of the pot is a good idea, sure, but we dont bother with that. When something is so obviously screwed up, we make the change and move on.

 

[Gooserider]

Ive no idea either, Goose. Should really be a no-brainer. Regardless of what method he uses, its likely the board. The pot isn't dealer-replaceable. Anytime we've seen issues like this, basically just like you said, its a bad pot. Theres really no need to overanalyze the issue...replace the board, be done with it. Harman requires the dealerto do the change. I just cant understand why he wont or cant. Its literally a 5 minute change, if that. the dealer wont be "out" the part, as they get credit for the bad one anyways.
Your testing of the pot is a good idea, sure, but we dont bother with that. When something is so obviously screwed up, we make the change and move on.

Agreed, no point in testing beyond the FRU (Field Replaceable Unit) level if you aren't planning to replace the pot, which you probably shouldn't - certainly not under warranty. Don't know why the dealer isn't doing it.

Now if it were mine, the unit was out of warranty, and I was looking at a $170 board, plus maybe a service call, I'd be firing up the soldering iron and looking for a replacement pot - I'd lay odds it's a standard item from any decent electronics shop, probably cost under $2.00, if that... As a dealerthough, it wouldn't be worth your effort, except possibly as a profit margin booster - I'd guess your cost on that board is probably in the $125 range, if you could fix it for $20 parts & labor then sell the customer a "repaired and reconditioned" board for say $100 then everybody goes home happy - you made more profit, the customer saved money, sounds like a winner!

Gooserider

 

[HarryBack]

Ok, under warrantee, its a no - brainer, since noones out anything, except Harman, or the manufacturer of the faulty board. NOT under warrantee is another matter. Yea, the pot is pretty simple and is almost certainly available from a 3rd party somewhere....so if the homeowner is knowledgeable enough to test and change the pot, like you and possibly GVA is (with Mrs-GVA's help, of course), most people here, including me, dont have the technical expertise to do so. Frankly, from the dealer perspective, I and my peeps have so many proverbial irons in the fire that Ive zero time to be troubleshooting circuitboards and attempting to fix them as well.

 

[GVA]

Ok, under warrantee, its a no - brainer, since noones out anything, except Harman, or the manufacturer of the faulty board. NOT under warrantee is another matter. Yea, the pot is pretty simple and is almost certainly available from a 3rd party somewhere....so if the homeowner is knowledgeable enough to test and change the pot, like you and possibly GVA is (with Mrs-GVA's help, of course), most people here, including me, dont have the technical expertise to do so. Frankly, from the dealer perspective, I and my peeps have so many proverbial irons in the fire that Ive zero time to be troubleshooting circuitboards and attempting to fix them as well.

Mrs GVA would be helping by saying hurry up and fix the damn thing... :cheese:

I figure in 5 years or so I'll have this thing tweeked completley, I'll have A PLC in there in place of the board monitoring everything from RPM of the motors to temps and even the level of pellets in the hopper and a ethernet card to monitor it at work on my computer.... :coolsmirk: It'll last forever.......

As far as the board I'd toss it it's most likely sealed, though if not sealed I may change the pot when I had free time..........like August.................2009..
Not much free time on my hands these days with the plant and Distribution Centers to deal with....... (and Mrs ;-) )