Year 4 with a DVC-500 not off to a good start.... Help!

McGiever wrote:

ablumny wrote:What no one can tell me, dealers, Harman, is are the symptoms i have indicative of a draft motor not spinning fast enough. Maybe ill send 110v right into the motor, ill spin full speed and that should answer my question

Yes, exactly, this is what I was saying a week or more ago.

Yep....I was focused on the combustion motor then. I ran 110 to that motor with no changes.

Now I'm thinking ill force the draft motor on full. But now this potentiometer thing???? I certaiTnley can solder new pots. Thanks guys...real good stuff

I pulled the board completely out. Coincidently the pot that controls stove temp is got a lot more physical resistance then the others. I know how to test a pot however these dont have the standard two ends and one wiper. They each have four leads. Plis i dont have the right meter at home. Ill bring it to office nd have a tech test them. It would be something to find that was the prob.....

ablumny wrote:I pulled the board completely out. Coincidently the pot that controls stove temp is got a lot more physical resistance then the others. I know how to test a pot however these dont have the standard two ends and one wiper. They each have four leads. Plis i dont have the right meter at home. Ill bring it to office nd have a tech test them. It would be something to find that was the prob.....

Yeah, thats the one I'd test first. Like you said.... running at Temp setting of '1' it was acting like Temp setting of '8', off the scale. I'll order a set of those pots, but can prolly get them cheaper at www.mouser.com

We DVC owners are waiting for the outcome. If this works I will keep a set of these in my little coal tool box. LOL. Then expect another diatribe about Harman from me - but first let's get that stove fixed without subsidizing the HNI (the Harman parent Co.) Lear Jet.

Wierd pot from ACP Technologies in Spain. Series VD11

http://www.acptechnologies.com/img/pdf/ACP_CA14-CE14.pdf

None of the catalog houses sell ACP. My engineer educates me a bit on pots statign the way the wiper and end leads are used to hold the pot in place and off the board, plus the plastic body and the shaft connection to the body is all crap. Interchangable shafts make for trouble at the base or somethign like that. (no doubt I didnt repeat that exactly how he stated it btw). Anyway, perhaps thats the reason the eBay guy claims they fail "all the time". I ordered a set from him.

MEanwhile, we had to disconnect one of the legs to take the POT out of the circuit and the suspect pot was not adjusting smootly at all. Mechanically its rough. Went ahead and tested the Feed Rate pot which I hardly touch and it was smoothly adjusting the scale. We swapped these two POTs and I will reinstall the board tonight, try it one more time and report results.

Expectations are low.....

Good thing I had no expectations..... No change. Unless the swapped pot is no good that theory didn't pan out.

The draft motor is wired to the pressure switch and control board. I've isolated the wires to the motor in attempt to run juice directly but that doesn't work.

So I wait for the service call which should be particularly interesting after the soldering work done to the board.....

We learn more from our errors as our successes. Of course, that is easy to say when my DVC is working. However, I am finding this thread fascinating I will bet he changes the main board anyway so what you have done to it does not matter. Perhaps we should make out a Visio chart (am I showing my age?) there can't be many more options left. What have we definitely eliminated? You know the old Conan Doyle saying - what is left is the answer. Can we measure the output from the board to the motors as we move the POTS, does anyone have a circuit diagram? Does your tech have a signal injector and can he trace where the signal dies? This is hardly the space shuttle and given the assembled intellect and experience here we must be able to solve it and all learn from this. Already we suspect we know how to build a more reliable DVC.

coalnewbie wrote:, does anyone have a circuit diagram?.

Yep....

You guys are hanging in here with me! Appreciate it especially when ive thrown the towel in multiple times.

That diagram is on the back of the stove on a door and i think in the manual. Perhaps i should have looked at it since i now see i wasnt energizing the draft motor at all! Thanks for pointing me back to it.

Im a pretty logical thinker and this thng s driving me nuts. By the way, im a Visio pro! One of my favorite pcs of software, use it all the time (not liking Visio 2010 though) Anyway, I think ill spend some time again isolating the motor and juicing it directly. Thats my suspect area. Dim led, never changes speed and barely anythng coming out of the pipe. If right however, why? Probe, board, motor, pressure switch...?

I think you guys are missing an obvious diagnostic solution...... Strip your stove of parts and drive over here !

This is my last day on this, im on biz travel for a week. Standby for next update
Andrew

Ok, diagram helped alot. Stove is not burning at the moment.

I isolated the draft motor, applied direct power and its spinning away, cant say any faster then when its normally connected. However theres very little air coming out of the pipe. I open the ash pan door and normal air amount is coming out so i figure since only the draft motor is running its starving for air. So then i isolate the combustion motor as well figuring itll pull in outside air and the draft motor will produce the right amount of exhaust air flow. Remember, both motors a now getting direct juice and nothing else is on. I close the ash pan door and the exhaust flow stops again as when i only had the draft motor on.

I was thinking about firing it up and leaving the ash pan door open a bit but i think the pressure switch would shut it down?

Am i right to beleive the combustion fan should be pulling in enough air to feed the draft motor........if so...youd say the combustion chamber from outside is blocked and not feeding enough air or the combustion motor is not functioning right. Im guessing.... Go back many posts and i had taken this thing apart down to the shell practically and saw no blockages.

Whoa!

The flow of air out the exhaust pipe isn't going to blow you away. It has to be moved at a certain speed, just fast enough to give the firebox a negative pressure. So as the combustion blower speeds up when you crank up Stove Temp to 7, then the draft motor just needs to speed up a little , to keep the firebox at the same negative level.
I notice my Combustion fan lite will be dim when it is idling at Stove Temp '1'. As I turn it up past '4' the Combustion fan lite will become full brite, so the computer must be varying the speed of the Combustion Motor to maintain the fire at the set level. Even at a Stove Temp setting of 4, my Draft lite is dim, meaning the computer does not need to bring it up to 100% to maintain the negative pressure in the firebox.
Just a thought:
Try measuring the output of the voltage from the main board to the Combustion blower, and see if it varies as you turn up the Stove Temp setting.

Have you pulled/removed the draft fan/motor completely out of it's housing?

Bet the housing is loaded up w/ flyash...this could be the blockage you haven't seen.

Fan will turn w/ accumulated flyash...but not move air effectively.

Break out the shop vac.

Good Luck

I can take a few measurements but based on this feedback im going to leave it alone and wait for service.

Yep, ive had the combustion blower are housng out for a throug cleanng.

Thx again guys. What an experiance!

McGiever wrote:Have you pulled/removed the draft fan/motor completely out of it's housing?

Bet the housing is loaded up w/ flyash...this could be the blockage you haven't seen.

Fan will turn w/ accumulated flyash...but not move air effectively.

Break out the shop vac.

Good Luck

ablumny wrote:I can take a few measurements but based on this feedback im going to leave it alone and wait for service.

Yep, ive had the combustion blower are housng out for a throug cleanng.

Thx again guys. What an experiance!

Not the combustion...the draft fan.

Yes sorry. Ive also pulled apart the draft motor and fan although you cant get the inside fan blades off despite an allen head set screw thats apparently never coming out. Thus without cutting the shaft, its staying put. I cleaned in and around from inside the ashpan area and behind. Ive cleaned the passageways to the outside.

Thx...