Harman DVC 500 Low Burn

Hello pamack,
You will need to get two new gaskets for the pipe connection from behind the stove through the wall.I listed the part # on a previous post. You will have to take the back covers off the stove to get to the pusher bar. There is a large bolt in the middle that holds it in place. Once that is removed the bar comes free. Check all the venting areas for ash. I am wondering if maybe a mouse has made a small nest some where in the stove and the bedding is just enough to cause your smoke problem. The TCP probe may look fine but might not be functioning properly. The dealer I bought mine from said if the new one didn't fix my issue he would take it back maybe you could ask if your local dealer would do that. No sense throwing new parts in that are not need. Did you take the T off the outside vent pipe and check for ash or a nest? I went crazy with my stove and not until I took EVERYTHING all interior and exterior pipes all fan motors (brush each fan blade with a wire brush to clean off caked on fly ash).completely apart and clean behind the pusher bar it did seem to correct the problem. The DVC 500 is a great unit when working properly but as we all know can be very tempermental !
The big problem is not enough support from Harman or at least a more detailed repair manual.
Regards,
Linda

Well I installed the new TCP tonight to no avail. I began the disassembly of my pusher assembly. Removed the back cover, doing this for the first time in 7 years. And when I remove the cover I find nothing but rust on the back of the block, the nut, plate, etc. Needless to say the bolt is so rusted it almost fell apart in the middle and is stripped. I lost my patience tonight and hope to find a solution to remove the nut on the pusher block tomorrow.

I did notice that the block doesn't look in to bad of shape so hopefully I can remove the block and for the 70 bucks get a new one and install. I'm truly afraid of this doesn't work in down to just the board.

Hopefully with the rough condition this is in, that this is the problem. At the beginning of my problems I noticed I wasn't getting enough heat. Perhaps it's because the feeder wasn't working effectively?

One more thing. I have checked all the exhaust piping for any possible clogs, nests, etc by taking them apart and there are no obstructions. This is a basement install so I do have. The interior Harman piping running up inside the house approx 6 feet before going to the outside.

Hello ,
I think you may have found the problem! Sounds like that pusher bar might be it!! The bar should be ok It's everything around it that might be the problem. I scrubbed mine clean with a steel wool soap pad. Pb blast and a vise-grip should free that bolt or try heat. Shoulder bolt part # 3-30-131180759 . I found hard coal dust under and around the pusher bar also clumps from the pusher bar to the burn grate I had to chip off with a screwdriver. I replaced all the gaskets on the door and ash door while I had the stove apart . I found a lot of ash that was clogging the fresh air intake in the slots around the exhaust pipes when I had to remove them to get to the pusher bar. I uploaded a photo. proper air flow is very important with the dvc 500. Hope I have been of some help. Let me know how it turns out.
Linda

A clean stove it the top priority, but in the end you will need to know if the fork has been spread open to a wider gap due to the motor pushing the "pusher block" with excess force from rust and/or dried coal build up under and around the block.

The fork measures just under 2" at its widest point.

Thank you all for this valuable input. You have far exceeded the customer service of any dealer I have spoken with and considering I tried Harman via phone and email and not heard back, tells me I'm in this without their support.

Something just doesn't sit right with me about this company and the dealers. That said thank you all for the prompt and valuable input so far!

pamack wrote:The fork measures just under 2" at its widest point.

And for those who are following along, are you happy with this?

I bent mine back to 1 13/16''. I used a large c-clamp with the fork still on the stove.My forks widen after some large pieces of coal got stuck in front of the pusher bar. I will repeat from a earlier post DVC-500 does not like wet coal use something to drain and/or dry out coal.I put the next load in a heavy cardboard box to drain and dry when I have wet coal.

Thanks. I may try that. In an interesting development I went to my dealer on Saturday to pick up some chimney gaskets and suddenly they were surprisingly helpful. I crossed a tech working in their shop and he gave me a few ideas but then when I explained where I lived he offered to come on Tuesday (tomorrow). He was going to be in my area anyway. Which was a real surprise considering the entire week before I only heard excuse after excuse of waiting lists, never get to my area, etc. So tomorrow afternoon we shall try again.

Well after 3 hours last night, and several different calls to tech still no solution. For the smoke in the box the Harman tech and the resident expert at my shop blame it on "wet coal" or wet in the box. I get the coal in bulk, store it outside and bring it in in 5 gallon buckets. I typically have enough buckets in my basement for at least a week and a half worth of fill ups. None the less a little bit of moisture was in the box so the thought was that moisture was causing the "sulfuring". At the end of the day that does not explain the problem that the stove lights great and then slowly fizzles to almost no fire at all.

Today I dried a different coal to see if it was a combination of my coal and it being wet. Due to the fact the techs seem to think its something in my coal. Ultimately different coal, dry, same problem, small amount of sulfuring, and fire lights great and then slowly dies down. Stove is in stove temp, on 4, and temp around 85. I normally run in stove temp, on 3, and temp around 75.

Thinking further about all the solutions offered on here I began to think this may be a feed issue. Being that my feeder was just disassembled and cleaned I checked the pusher block to be sure it was installed correctly, and it was, rounded edges to the bottom. So I still had the stove lit and decided to place a shim in the tuner fork, taking the opening from just shy of 2 inches to just shy of 1 3/4. We'll see how this goes.

The tech tested everything he could think of and all the fans, pressures, etc. tested well. Only solution they could generate was let the stove sit open and empty for a few days to dry out. Also let some coal sit in a place that it can dry out, and go from there. I told them I didn't think I'd have the patience but they said try that and they will be back in touch next week.

I'm on my last hope with the shim in the tuner fork, so we shall see. Thank you all for the input and ideas.

I posted the previous on Jan 28. Just returned and lit up my stove again tonight. This time with the super dry coal. No smoke coming from the box, and the fire lit up and stayed high with the shim in the tuner fork. So now without the smoke in the box I am getting a high reading of CO in the house.

My alarm went off so I had to shut it down. Checked all the seals and near as I can tell they are in decent shape. I think by just eliminating the smoke from tw box I just cannot see what is coming from there now like I could previously. Off to call the dealer tomorrow and see how It goes. I'm not expecting anything over the top but it's my only hope.

Using a multi meter, check and read the resistance (ohms) of just the probe.

Somewhere on this board is listed what a good reading is.

That was me.

You guys are doing grat work but one thing to eliminate is the ESP and TCP probe. So you went from an old style circuit board to a new one. What color was the probe then and what color is the one you are using now. It will be either black or red and they are very different. I participated in an old thread some years ago on this one. I think one is 100 ohms (old black one???) and the other 1000 ohms (newer red one???). Red probe goes with newer style board. As I remember the old probe provided the power to the board and when it shorted out that would sometimes blow the circuit board by overvoltage, hence the redesign. I will try to get this addled old brain back into gear for you. Can you use a volt ohm meter, if so we will try something. Let us know.

How far is the base of the chimney from the ground and is the base open or closed. How far above the snow line? Is your chimney clean, those pipes get really cruddy beyond the ESP. Is the stove breathing right, look for an obstruction to the air intake? It would appear you have eliminated that one but I am very suspicious. High CO means incomplete combustion and that means chimney exhaust or combustion fan. These units are well sealed so CO detectors going off is definitely wrong. Is this a basement install and low far does the pipe travel down to get to the stove (if at all).

All this stuff brings back my nervous tick as our dealer is useless. However, our DVC is running flat out in this weather and working just great but I NEED it to keep going. I too have had the board rebuilt by the Ebay guy -- good source. They are great units when running.

When I took the chimney pipe apart to clean and inspect it never dawned on me but the bottom most piece, the first turn for exit air to turn up, the inside chimney may have been worn. I seem to recall thinking that turn didn't look bad but I didn't inspect too closely to see if the joints were cracked or broken. If they are, that could be crossing the exit air with the incoming air. If that is happening could that be the cause?

My old ESP had a yellow wire and my new one had a yellow wire. I can check the resistance across the switch just to be certain but being that they were the same color and the dealer did confirm multiple times the color of my wife I thoufht I was good on that front.

Base of the outside chimney from the ground is approximately 3 feet and it is uncapped.

This is a basement install. Stove sits up approximately 1 foot off the basement floor. Inside chimney comes off the back of the stove, runs approximately 5 feet and then makes a turn and exits to the outside.

Thanks for the quick replies and assistance.

My old ESP had a yellow wire and my new one had a yellow wire. I can check the resistance across the switch just to be certain but being that they were the same color and the dealer did confirm multiple times the color of my wife I thought I was good on that front.

Looks like we can eliminate that one then. Looks like it might be a chimney issue still .....

Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.
Arthur Conan Doyle

Good luck.

Has anybody measured the draft on this unit recently?