Atwood Hydroflame DC-82 Troubleshooting

[Stripe]

Okay, the wires were RE tested using TOW multimeters, one a cheapie and the other the original much one I used the first time only this time with a good fuse put in place.  Both meters read 13v.  That means wiring is good to go there.  Now to just figure out how to get my furnace working again..  Hm?


BTW, Dave, took a pic of the circuit schematic on the side of the furnace.



It shows a breaker in the circuit but I'm not going to get my hopes up until I can squeeze my head in there and have a look around inside the unit.

[DaveVA78Chieftain]

If fan is not even starting:
1. Power from 12VDC supply fuse is supplied to furnace pin 1 AND the input power pin on the Thermostat.
2. CB only controls power to blower motor WHEN time delay relay is energized.
3. When Thermostat turns ON, power is applied to furnace connector pin 3 and on to pin 4 of the time delay relay.  There is a 15-20 second delay before the time delay relay energizes allowing the 12VDC on pin 5 to be passed on to the orange blower power wire.
4.  While power from pin 4 is also applied to the sail switch, the sail switch will not turn ON until the blower motor gets up to speed.  No blower motor means no sail switch, no spark, no gas valve turned ON (power never gets applied to the DSI control board).

So, this problem could be:
A. No 12VDC to Furnace input connector pin 1 or Thermostat input power pin.
B. Thermostat never applies power at Furnace input connector pin 3
C. CB is OFF
D. Relay is bad
E. Blower Motor is bad
F. Broken wire.

All this is basically written on pdf page 39 (page #38) of the manual I pointed you to.

Dave

[Stripe]

So, while unloading unnecessaries from the 'Goose' I decided to just close up the furnace housing and deal with it after I returned.
After I finished with all that and was loading her up for the trip I fiddled around once more with the thermostat.  Dunno why, just did.  What I did was grab the end of the spiral thermal spring that had the contact on it and wiggled it side to side while it was against the other contact after I turned up the thermostat and removed the cover.  Suddenly I was distracted by someone knocking at the RV door and forgot I did that long enough that when I went back to doing stuff, I didn't immediately notice that the furnace fan was running. No heat mind you because I had not turned the gas back on, nor did I reconnect the supply line back up to the furnace. This gave me a little glimmer of hope..

I turned the thermostat back down and reconnected the LPG supply line and turned the knob to the ON position.
I then lit my stove and oven to get the LPG into as much piping as I could.  After that I went back to the thermostat, replaced the cover, set the on/off switch to on and turned it back up.  It always takes about 30 seconds for something to happen so I started putting things away. After I stowed some gear, I noticed nothing was happening with the furnace.  I went back to the thermostat and pulled the cover off and moved the spring contact point side to side again, waited the thirty seconds and sure enough the fan kicked in again. THere was no heat this time either but the manual says that if the gas has been off for a significant amount of time that a restart may be necessary. The manual was right. After turning the thermostat down and waiting the requisite 3-5 minutes I turned it back on.  Sure enough, there was a beautiful blue flame going on inside my furnace and heat finally started coming out of the registers. I will clean the contacts with contact cleaner.

Beautiful Blue

[DaveVA78Chieftain]

 

Consider replacing thermostat with a digital one

Dave

[Stripe]

I am in fact on the prowl for one..

[legomybago]

I need to replace mine also (unless I can magically fix the broken plastic housing cover?) You say go digital Dave? Thats what i'll do if I replace.

[TerryH]

Couple of months ago I changed my thermostat to a Honeywell RTH2410 (digital) and it is great.
Liked it so much that I changed out both my Mother's and Sister's - both had the coil/temp spring type.
They both like it as well.

[M & J]

Once you go digital, you wont go back.

[DaveVA78Chieftain]

R terminal is 12VDC from battery fuse
W terminal is on/off signal to furnace

http://appliancejunk.com/forums/index.php?PHPSESSID=a44b16238fc06ba63f6fbaeebfddb0b1&topic=2912.msg11007#msg11007

Dave

[TerryH]

That is what I was told by Honeywell as well. Remove the factory jumper, then R and W/Aux. for a two wire set up.
Great thing with Honetwell is that they provide a ph. no. for their help line and if you call it you get to speak to a real live human being.

[Oz]

PO had installed a Honeywell in mine.  Worked just peachy.  I think I was lucky.  Just about everything the PO did, he did right.

[Stripe]

Sweet, good info, thanks gang..

[Stripe]

I got the Thermostat today installed it and it works just great!  Thank you Dave for the wiring info, helped BIG time.

I took pics of the install and will post after Easter Meal..