DVC-500 Troubleshooting Help

CraigZ · Post by **CraigZ** » Mon. Dec. 07, 2015 1:01 pm

I don't post often, but visit here several times a week since I bought my DVC-500 in 2008.

I've had very few issues with the stove (knock on wood...) and absolutely love the "heat to cost" ratio. Last year, I thought it burned a little hotter than in previous years and it started doing the same this year. Setting it at the lowest stove temp (never really used the room temp setting) just wasn't low enough anymore so I took everything apart, made sure the TCP and ESP probes were in good shape (they were), cleaned the FSS filter, and vacuumed every last speck of dust from in and around all the motors. When I started it back up, things were much better and I was pretty proud of myself for "fixing" it. However, right after removing the ashes for the first time, the temperature once again started rising despite the settings remaining the same. I was able to solve the issue by turning the other knob to "off" and then slowly turning it back on.

I'm afraid the problem is coming from the control board, but don't really want to admit it just yet because of the replacement cost. I was hoping someone on here may have some other ideas....

Thanks in advance.
Craig

WNY · Post by **WNY** » Mon. Dec. 07, 2015 7:59 pm

Sometimes the rheostats or variable knobs get a worn spot from being in the same position, so rotating them all around once in while and cleaning with canned air and or electronic parts cleaner (spray non residue type) can help keep them clean.

CraigZ · Post by **CraigZ** » Tue. Dec. 08, 2015 7:27 am

Thanks for the suggestion. I'll give that a shot.

Craig

Post by **fifthg** » Tue. Dec. 08, 2015 9:35 am

I lean toward that particular rheostat being the problem,as opposed to the circuit board being the culprit.I have had A dvc 500 since 1999,and have only had to replace the exhaust/venting motor in all that time.The stove has been very forgiving maintenance wise.I don't even have my grates cemented in place,as is recommended.I have no troube with that,and they are easier to clean that way.I also didn't go with the exterior candy cane exhaust they recommend.I just have a horizontal 4" x 18" semi-elbowed diesel tail pipe so that the exhaust is not pulled back into the intake,which probably wouldn't hurt too much anyway.Harman can't recommend this type installation for liability reasons.Coal burning is more an art form than a rocket science.You may need a rheostat if cleaning yours does not work.I do run mine on the lowest possible settings almost all the time.

CraigZ · Post by **CraigZ** » Tue. Dec. 08, 2015 5:51 pm

fifthg,

Thanks for your comments. I noticed in another post that you mentioned you had to replace one. So a dumb question...are the rheostats you are referring to the same as potentiometers (POTS) referenced in other posts on this forum? If so, these need to be soldered in and not just "plug-and-play", correct?

Post by **fifthg** » Tue. Dec. 08, 2015 6:20 pm

Craig,I am not sure which other post you are talking about.I never replaced a rheostat.Sorry,I can't answer your question.I broke a control knob off one,but could still operate the switch without it.Someone else will probably be better versed on the issue and will be able to help you.Did you try cleaning it yet?Sometimes a rheostat will just have a bad "spot" on the adjustment range,and you can get by by just staying above or below that spot.

CraigZ · Post by **CraigZ** » Tue. Dec. 08, 2015 8:16 pm

fifthg wrote:Craig,I am not sure which other post you are talking about.I never replaced a rheostat.Sorry,I can't answer your question.I broke a control knob off one,but could still operate the switch without it.Someone else will probably be better versed on the issue and will be able to help you.Did you try cleaning it yet?Sometimes a rheostat will just have a bad "spot" on the adjustment range,and you can get by by just staying above or below that spot.

My bad. I read your reply to a "jim02ss" where he mentioned replacing a rheostat...

Another dumb question...how do you go about cleaning a rheostat?

Post by **fifthg** » Tue. Dec. 08, 2015 9:00 pm

sometimes just rotating it back and forth will,by friction,get it to clean itself,if you know what I mean.you might also be able to use a pencil eraser to rub the contact surfaces until cleaned.A di-electric points cleaner or canned air blast might be all it takes.Switches respond well to WD-40 spray,but that will leave a film that will attract dirt and haunt you later.I get braver with my methods if I figure it is alreay broken.You might have to replace it anyway,so there is not much more to lose.

Post by **fifthg** » Thu. Dec. 17, 2015 5:54 am

Well I'll be a sonuvagun.I jinxed myself and my DVC.I turned it off after Thanksgiving when the kids went back to school.Thay have returned for Christmas and I fired 'er up again.It seems to only run flat-out now.I messed around with the rheostats,but they are soldered in and hard to get at without removing the circuit board,which I have not done.Now I am wondering if you have been able to figure yours out Craig.Has anyone else had similar loss of control with their DVC 500?

Post by **fifthg** » Thu. Dec. 17, 2015 7:21 am

after taking my own advice and working rheostats on and off,running each control thru every function,and unplugging unit entirely for about 5 minutes,and between the time I just posted and now,it is working fine.So much for being a jack of all trades and a master of none.Being a fearless jack of all trades is my great strength while being a master of none is my weakness.Some say "booze helps".I say a sense of humor does...Never mind.

McGiever · Post by **McGiever** » Thu. Dec. 17, 2015 7:29 am

In the off-season send the board and new rheostats and I'll do the solder work for ya.

coalnewbie · Post by **coalnewbie** » Thu. Dec. 17, 2015 7:45 am

There was a guy offering to fix DVC boards on Ebay for about $50, I will see if he is still in business.

Post by **fifthg** » Thu. Dec. 17, 2015 12:56 pm

Very generous offer,Thanks McGiever. Also,thank you Coalnewbie for your offer.I will see how it goes.I have the unit sold and will run it 'til after the holiday.I told the guy,my friend,about the situation,so I will relay the info.He is very handy with such things,and doesn't seem at all concerned.I sold it because I am going to use a beautiful old Hotblast Peninsular that I have finished restoring.The guy I got that from did a nice cosmetic restoration and nickle plating,and I did the rest,fixing cracks,sealing,replacing mica,and lining the firepot with "super hybond plus".That worked out very well and I am anxious for some cold weather.It is in a 400 s.f. room with high ceilings and lots of windows.Cold weather for Christmas would be a great present.I only used half the hybond plus if anyone needs some.It is enough to do a large firepot,and is easy to work with.If one of you guys wants it,it is free.Any one else,$20 plus shipping.

CraigZ · Post by **CraigZ** » Sun. Dec. 20, 2015 6:27 pm

fifthg wrote:Well I'll be a sonuvagun.I jinxed myself and my DVC.I turned it off after Thanksgiving when the kids went back to school.Thay have returned for Christmas and I fired 'er up again.It seems to only run flat-out now.I messed around with the rheostats,but they are soldered in and hard to get at without removing the circuit board,which I have not done.Now I am wondering if you have been able to figure yours out Craig.Has anyone else had similar loss of control with their DVC 500?

All I did was turn all the knobs a few times in both directions and seemed to make a little difference. To be honest, I think I only burned it for a day or two until shutting it down because of the warm temps. I haven't turned it back on since.

Craig