Harman Accentra blowing 6A fuses?

[womaus]

Greetings,

After a rather uneventful burning season my Accentra FS has decided to start blowing the internal fuse.

This stove is on a UPS.

The only issue I've been having is the combustion blower stays on, never shuts off, even when the stove is fully off. Need to pull the plug to get it to stop. My plan was to take care of that when I can get it outside for a full spring cleaning.

Sounds like a bare wire, crossed wire? Again, no real issues up until last night. Replaced the 6A with a 5A this morning, immediately popped it when plugged in, i.e. no status lights etc.

I'm hoping it's not the board itself...I replaced it 15 months ago. $$$$.

Any ideas? I'll be pulling off the back of the stove, taking a look at what I can without pulling it away from the wall. Only have a few inches clearance.

Thanks in advance...

 

[womaus]

And while I have you all here, can anyone tell me what this switch actually does? I noticed no difference in performance of the stove when I was trying to figure it out last year.

This is on the interior wall of the control panel area. Hidden when the control panel door is closed.

Sorry for the poor image, juggling a flashlight and camera at the same time.

 

[womaus]

And to be sure I'm providing all of the needed info, here's a pic of the fuse in question. The control panel has been pulled off of the stove.

 

[jackman]

And while I have you all here, can anyone tell me what this switch actually does? I noticed no difference in performance of the stove when I was trying to figure it out last year.

This is on the interior wall of the control panel area. Hidden when the control panel door is closed.

Sorry for the poor image, juggling a flashlight and camera at the same time.

View attachment 196108

The switch is a high/low blower setting for the distribution fan. It is in addition to the dial on the control panel.

As for the fuse blowing I can't say for sure but it does sound like something is shorted. I'd start by using an ohm meter and checking the resistances of each connection to the control board and testing the individual motors.

 

[womaus]

I'd start by using an ohm meter and checking the resistances of each connection to the control board and testing the individual motors.

I'll get the coffee started...how soon can you be here?

Looks like I'll be pulling the stove away from the wall. This thing is heavy...

 

[womaus]

Back of the stove is relatively clean, haven't vac'd back in the internals since last year. Distribution and combustion fans are clean. Fines box approx 5% filled, wing nut holding it on was a bit loose.

Pulled and alcohol wiped the thermistor. That too was in clean, good shape. Exhaust area was clean, very little ask coating the vent. Same with outside venting (easy to access and pull apart).

Adjusted the chain drive for the pellet feeder (older Accentra)

Unable to find any worn, cut, frayed wires. No "flash" marks. Will re-tie and tape wires as needed for future protection.

Didn't see any problems with the distribution or the combustion fans over the past months. No laboring, no squeals. Not sure how to use the tester to verify. The coffee is getting cold by the way....

Unable to find 6A AGC fuses at the big box or local hardware stores. 5A, 10A, 15A no issue, lots of stock on shelf. No 6A though. Ordered a set of 5 through Amazon, should be here in a week.

Should the 5A AGC I have on hand fit the task? Or am I courting trouble here?

Going to finish up the clean, get it back together. Will be trying a 5A AGC (but will check back here before doing so).

Thanks again...

 

[womaus]

The switch is a high/low blower setting for the distribution fan. It is in addition to the dial on the control panel.

That's what I was told before. I could never see any difference in the performance. Maybe the stove wasn't running long enough, hot enough when I was try to determine?

Thanks for the reply...

 

[womaus]

The topic of the Harman OAK kit has come up in the past.

Here's a couple of pics of the install...I used one of the Harman OEM vent kits, has OAK integrated into the assembly. I'll get a pick of the outside of the house once it's all put back together.

Used automotive flex hose for the OAK connect wall to stove.

 

[womaus]

One last post for a while...may try to run the 15 miles to the Harman dealer for the correct fuse.

Put it all back together, double checked everything. Attached heavy duty HEPA vac to the exhaust and attempted to start the stove in Test Mode.

Got 2 or 3 seconds of startup lights, then the fuse flashed and popped.

So I've got a short somewhere...

 

[womaus]

Pulled auger leads, tested, blew fuse.
Pulled Dist fan leads, tested, blew fuse.

Out of fuses. Off to the dealer.

 

[womaus]

Dealer was a little helpful, was able to ascertain the OEM is a 6A AGC fuse. None in stock.

Unable to test the control board.

Gave a couple of recommendations for further troubleshooting. Pull the igniter, lessen the load on the startup. Start in manual setting.

Will wait for the Amazon order to get here.

Ah well, we're almost at end of season?

 

[Border1225]

If you have a Radio Shack around you, you can get the fuses there. I had the same problem with my 2006 Accentra FS this fall, sometimes the fuse would blow while running, and if it didn't, the combustion blower would never shut down. Unfortunately in my case it ended up being the control board.

 

[womaus]

Radio Shack didn't even enter my mind. Just went by one going to one of the older hardware stores in the area. Will stop over there now.

When I first installed this stove I had the same issue you described...stove not shutting down. I replaced the board at that time, things were good for the past 15 months (6 - 7 months of heating time?). I'm hoping it's not the board. I think I spent $180 for one last year

Off to Radio Shack. Didn't even think they were around still.

 

[Border1225]

These are the ones I got from my local Radio Shack.

 

[womaus]

If you have a Radio Shack around you, you can get the fuses there.

You were right, Radio Shack did indeed had the fuses. Two packages of four in the bin, 60% off regular price. Bought 'em both. This store is closing up at the end of the month.

Put the stove back in order, tried one of the 6A. Popped it just as quick as the 5A fuses. I'll need to get deeper into this, possibly over the weekend.

If anybody out there can give basic instructs on multimeter use I'd be most appreciative. I know the fans and auger are all 120V, I can easily put together a pigtail connector to test those out for spin...it's the controls I'm uncertain of.

Thanks in advance...

 

[womaus]

Multimeter time. I got the black lead on COM, the red on VΩmA. Reading will be taken on 2000k, 200k, 20k, 2000, 200 (see pic below)

Interesting that the igniter yellow goes straight to the interface plug to the board. The igniter light blue wire pigtails off from the vacuum to the auger / feed motor. I've pulled the connector to the auger motor, hopefully isolating the igniter for testing. Will take readings from the yellow wire plug interface and the light blue female connector pulled off the vacuum. Control board is out of the stove.

Readings are:

Multimeter on, leads not connected to anything = 1

2000k = 000

200k = 00.0

20k = 0.05

2000 = 049

200 = 48.6

Everything has been double checked, above readings are correct.

Can the knowledgeable people here comment? Can we rule out the igniter, verify it as working?

Many thanks.

 

[womaus]

Found this searching the forums:

If you run the resistance test on em before they're installed,
you should be getting a reading of 45 - 49 ohms.
Those are the good ones...

So I'm betting the igniter is good.

Still need to test the combustion motor.

 

[jackman]

You're doing great Womaus. You can check the validity of the VOM in the ohms range by selecting the 200 scale and then touching the probes together. Your reading should be zero but the Harbor Hate meter will probably read somewhere around 5 ohms or so. Keep verifying one item at a time in an attempt to isolate what might be causing the fuses to blow. Hopefully, it's not the board.

 

[womaus]

You're doing great Womaus. You can check the validity of the VOM in the ohms range by selecting the 200 scale and then touching the probes together. Your reading should be zero but the Harbor Hate meter will probably read somewhere around 5 ohms or so. Keep verifying one item at a time in an attempt to isolate what might be causing the fuses to blow. Hopefully, it's not the board.

Thanks. May start up on this Saturday...tomorrow is St Pats, having a bunch of people over for CB&C in the evening Need to clean up my mess of today.

I'm hoping the solution will come to me while I sleep....

 

[jzm2cc]

The control panel pivots and if swung open/closed a lot, it can lead to chaffed wires in the bundle area just above door. Also check white connector to control board for signs of heat discoloration.

If this was my stove I'd be tempted to unplug all unessential loads (convection fan and igniter) and see if it runs ok when run on low heat setting after manually starting it. If ok try adding convection blower and eventually igniter back into equation. If this doesn't help then you'll have to start ohming out circuits to see which load or circuit branch has too low of resistance (short).

Exhsust fans that don't turn off can sometimes be a bad ESP, or control board issue.

 

[Lake Girl]

Did you get the last board repaired or replaced with new? Just wondering if you cured one problem on an old board and have a new issue in a different area...

 

[womaus]

Did you get the last board repaired or replaced with new? Just wondering if you cured one problem on an old board and have a new issue in a different area...

Last year it was a new board, new thermistor. As far as I know the only repairs possible on these boards are the potentiometers? Or is there someone around that will do deeper diagnostics and repairs?

We've recently had some full power outages, only lasting for a few seconds to a couple of minutes. We've got underground electric feed, so not as likely to see outages from downed trees, cars hitting poles etc. The stove connects through an APC Back-UPS 600, mainly for the line conditioning than the battery aspect. But I'm wondering if these recent outages have had something to do with it.

And sleeping on the problem didn't fix it. Damn.

 

[womaus]

The control panel pivots and if swung open/closed a lot, it can lead to chaffed wires in the bundle area just above door. Also check white connector to control board for signs of heat discoloration.

Exhsust fans that don't turn off can sometimes be a bad ESP, or control board issue.

The wires in the pivot area are in good shape, no cuts, crushes, etc. White connector looks like it's brand new.

Last year the Combustion/Exhaust fan wouldn't turn off, a new board and thermistor fixed that (after trying a thermistor first). This year the problem started about a month ago with the same fan not turning off. I did my best to check the newer installed thermistor, it seems to have the correct resistance. The fuses popping have me a bit baffled, and worried that it's deeper.

I'm betting it is gonna be another $180 board....

On a side note, a friend with a Harman that was going on 18 years of ownership recently came home to a smokey house, the wiring harness behind the control box area was spitting flames and sparks. When I found out I thought he was making up stuff. I stopped over to take a look, and indeed the harness was toast. Very strange. Could have been 18 years of household dust, cat and dog dander?

Had the local Harman dealer take a look at it. They stated it could not be repaired due to the age of the unit. He replaced it with a new, store demo Harman.

 

[Lake Girl]

That's an inexpensive board compared to others ... board repair services charge about the same. Not really something I understand well but have seen discussions on triacs on the boards (beyond the potentiometers).

Is it worth trying to get a new harness or is it just a matter of replacing spade connectors?

 

[womaus]

Is it worth trying to get a new harness or is it just a matter of replacing spade connectors?

The board I picked up last year was OEM from one of the local Harman dealers. The other dealer in the area was well over $200 for the same part #.

I've considered a new harness, and have been looking to see what the cost is. I need to get back behind the stove to fully peruse the existing wiring...and test fully the fan motors. If I see damage to the harness I'll look further into replacement.

If the harness shows no visible signs of damage can it still be faulty? The copper degrading due to heat, age? I can see the need to clean and reseat he spade connections, oxidation and all that, but the harness itself? Would an older harness blow fuses?