Harman Advance Combustion fan issue

[SteveM07825]

Hi All,

Newb to this forum, so bear with me. I have two Harman Advances and I love them. My older advance is now playing up and had a #6 flash warning on the Control board. Found and resolved that issue! My new issue is baffling. Simply the combustion fan stays on 24x7 stove cold until I pull the power..

The board for the Advance is I believe the one that is used in the Haman P68

I have:

• First cleaned and then changed the ESP (blackwire)
  
• Swapped out the vacuum switch
• Clean out all the holes in the burn pot
• New gaskets
• Changed the room therm and relocated.
• checked the draft door and its clear.
• checked the feeder and vac'd out all fines
• Cleaned combustion fan blades.

Auto mode:

The stove lights normally, burns normally, pellets feed normally and stove adjust temp on demand normally, all fans run normally and speed can be controlled.

Manual (fireplace) mode

• Stove can be lit using gel
• Stove feeds
• Dist and combustion fans run normally

Known issue is that the room temp pot on/off may need cleaning (has sweet spot).

So... thought I knew my stove inside out, but right now, I am at a loss.. I am guessing that may have a control board that is going or has gone bad. Hence the call for some advice... I have searched the web and other sites and not found the definitive answer anywhere. So does anyone here have a diagnosis method to confirm a bad board. I am not a dealer and don't have the Harman DDM (though i would love one!!)

I am also electronics trained so could probably repair the board to component level, if I had the diagrams and test points. (anyone out there have this info?).

One final question in this post is: How is he board removed from the stove? Are panels needed to be removed? Where are the screws that hold the darn thing in place. Does anyone have the procedure for proper board removal down on paper or some UTube vid or something that explains, that does not require a hammer or a contortionist!!

Enjoy reading the comments and experiences on here, happy to have found this board..

Thanks in advance

Steve M

 

[Delta-T]

assuming everything else works normalish, I'd say its a faulty ESP probe, or the rom is really warm and tricking the stove into thinking it should run the blower. That blower wont shut down until the stove thinks its below about 90 deg at the ESP probe. IF you have smoldering pellets in the ash pan it can trick it as well.

 

[SteveM07825]

assuming everything else works normalish, I'd say its a faulty ESP probe, or the rom is really warm and tricking the stove into thinking it should run the blower. That blower wont shut down until the stove thinks its below about 90 deg at the ESP probe. IF you have smoldering pellets in the ash pan it can trick it as well.

Based on your thoughts I am now leaning toward the control board. As I said I first cleaned the ESP, with Isopropol, ran the stove, had the same issue. Then Changed out the ESP for a new one, again with the same issue.. The ESP is I think a simple bi-metal thermocouple feeding back sensor voltage to the logic board. It does it bit and viola we have fan control.. If I am correct the ESP controls that combustion fan.

The stove temp is well south of 90 and there is definitely no smouldering pellets in the ash box exhaust temp is at ambient room temp +-68 measured on my digital MM.

That's the condudrum.

Still need to know the easiest way to extract the board from the Advances' innards ??

Thanks for the reply and insight, all other suggestions, insights and tips welcome !!

 

[SteveM07825]

Update..

Discovered that unplugging the ESP from the board will stop the fan. Plugging it back in and the fan stays stopped.. Restart the stove and the fan runs, but wont stop again.. New ESP... !! WT !**!

Any clues about removing this board.. Please?

 

[SteveM07825]

Still looking for some information on removing the control board from the advance.. can anyone pass on any method to remove the board??

 

[Lousyweather]

take the knobs off, unplug the wiring, pry it off the standoffs?

 

[rickwai]

Board removal is easy. unplug stove, remove knobs then reach up and gently wiggle board off the pins, just a friction fit. Before doing that check stove when it is shut down and fan is still running, see if there is any heat in the burn pot. I did have a harman one time that the igniter was not shutting off and the heat it was producing was enough to keep comb. fan running. That required a new board.

 

[P38X2]

If you end up removing the board, be gentle and try and lift if off as straight as possible. When reinstalling it, use the same caution. If you have a bad angle and are in a contortionist position, it's VERY easy to bend the ends of the standoffs closed or open. If this happens, you'll have to re tweak them. STRONGLY suggest taking the time to remove any panels necessary to make accessing it easier.

 

[SteveM07825]

Thanks all.. I figured it may have to be a contortionists enterprise.. I asked because someone mentioned screws bolts etc that I could not readily see.. I shall take a look this weekend!!

I did check the ignitor and that is definately cold to touch.. The fact that I still see the #6 error code and I changed the ESP for a new one, is leading me to suspect the board..

I shall report back..

Thanks again

 

[rayttt]

If you changed the ESP...did you get one with the same color wires?
if not Switch 5 needs to be switched on pcboard.

If you still get a #6 error...check the wiring where it connects to the board..mine gives me alot of trouble there.

 

[SteveM07825]

Hi thanks for the advice... As for the wires they are the same, I have the blackwire version, so no dip 5. This stove has just been thru a major move, I am assuming a dry joint or something unseated.. Fact is, it shows incomplete combustion, an has to be ESP or something related.

Many thanks for the suggestion, I shall pass on all resolution info.. This seems to be perplexing issue for many!

Mine has gone out three times tonight !

 

[SteveM07825]

OK, over a week into my fix, and I believe its all done. The stove is running happily and with no further issues. I made the assumption that I was dealing truly with a connection issue and probably dry joints at the control board. I went for the common item, pots, transistors (especially those on Heatsinks) and off board connectors where component plug in or onto the control board. I do have to mention that I did order a new board for the stove, and decided to entertain fixing the old board knowing that the new one was on the way!!

I DO wish I had Harmans DDM, that would have made the diagnostics easier!!

My Fix:

This is MY fix, I do not recommend this to anyone! This is for information only. Read the whole thing first!!

Extract the board, quite simple if you have contortionist abilities. Pull the power, pulled the knobs, reach up and pop each corner one by one. The board drops and then you can unplug the harness. If you are wiring challenged 'Take a picture' but there only a few wires on the harness and it easy to see where they go..

With a Stiff brush clean the board, remove the dust from all the components side. Dust is an insulator, and heat, is the death of electronic components.

Clean the back side (solder mask side) with Isopropol Alcohol especially around the solder joints to the Pots, the ESP connector pins and the Transistors.

Re-solder each of the pot connections (wiper and track) to the board. Basically with a clean iron, small electronics tip, and VERY minimal amounts of good quality fluxed solder, tin the bit just enough to wet the bit. Apply to each of the pot connection pads until the solder pad JUST brightens (melts) the small amount on the iron will also transfer. let each joint cool for a few seconds before repeating the process on the next pad.

Once all the Pots are done, check that you have not bridged any pads accidentally. Don't use great gobs of solder, its not needed!

Next:

Pull of the plastic socket from the pins to the ESP connector, (so you dont melt it). Flip the board over on a pad or towel, and re-solder the two pins one at a time, letting each cool for a few secs. Again tin the bit with minimal solder and heat until the pad brightens and you get transfer from the iron. Let cool and then replace the plastic socket on the pins.

Next:

There is a group of Transistors on heatsinks, flip the board and re-solder each pad on each transistor, using the process above. DO NOT bridge the pads, use minimal solder, and just enough heat to melt the pad no more than that. We are not welding here

Final step:

As the pots are sealed, you cannot take them apart (DON'T be tempted to DO IT!!). They are however vented. Cleaning the track and wiper can be acheived by getting some switch/electronics cleaner (Radio Shack) and with the tube squirt a little into the pots at the tiny vent holes (on the side), clip a knob on first so that you can rotate the wipers back and forth a few times, that will loosen up any oxidation, one more squirt to wash out and rotate again (it has a lube in it ), next pot etc. Be frugal with the cleaner you don't need a lot!

Check your Dip Switch settings are correct, mine were not and and not been since installation of the stove 5 years ago!! refit the board and try.. If it works Great, if not... Well you know you have that new board on the way anyway ;-)

WARNING do not use some iron designed for welding ships or a torch etc, Get a good electronics iron and ersin multicore solder. DONT USE ACID FLUX on ANY electronics. Heat the pad at the SIDE of the component pin, do not press down on the pin, you dont want to push it out!! If you are not good with an iron. DONT TRY this, you WILL screw up the board! I take no responsibility for what you do with this information.

One thing to note. If the board is blown, no amount of soldering will fix it. This fixed my #6 error flash with a Blackwire ESP probe and the refusal of the stove to shut down the combustion fan even when cold.