All ActivityMost RecentMost LikesSolutionsRe: Atwood RV Furnace will not start after changing propane cylFirst let me thank everyone for their response and input. It is great to always know you can get such help and assistance from RV friends. No, I have not gotten to the bottom of our furnace problem YET! However I am convinced we will resolve the issue with your continued assistance. I have taken most of our RVision's 8226 Trail-Lite apart and have found nothing significant, but a few interesting issues. Everything works normally except the furnace, Atwood 8531-IV-DCLP, and the Propane LP Detector, Atwood Protechtor series 2001. (We have a 30 amp Internal Surge Guard) I thought the LP Detector, which had malfunctioned for several days, had failed and had purchased a replacement, Atwood model 36719 LP_DOW. I installed the new detector and it did not work, 12.4 vdc and correct polarity. I thought it was DOA, called Atwood and they said to return it. The concurrent problems with the furnace, the detector coupled with your inputs made me curious about the low DC voltage. I hooked the old detector to our Wagan Power Dome EX and it functioned properly. The DOA new detector also functioned as designed when tested in the same manner. (According to Atwood "this alarm has a seven year life." It also has an end of life mode and states it must be replaced after it has been powered for 7 years +/- 128 days. Had any of you heard of this? Does it apply to the series 2001?) I then pulled my 12 volt battery and it tested at 13.85 volts, but I was only getting 12.45 volts to the Detector. Next I started checking out the DC portion of the Power Supply/Converter. It is a Parallax 45 amp, series 6300, model 6345. It has nine(9) DC lugs fused at 15 amps each. The first six (6) are unfiltered and the remaining three (3) are filtered for accessories such as the stereo and such. The furnace and LP Detector are connected to unfiltered lug #5 which is at 12.25 volts with shore power connected. (All six of the unfiltered measure the 12 25 volts with shore power and 12.45 volts without. The three (3) filtered lugs measure 13.81 with shore power and 13.0 without. The LP Detector works properly when connected to one of the unfiltered lugs. Tomorrow I will connect the furnace and LP Detector to this lug and see what results. Is this voltage drop between these lugs normal? What would cause this drop? Have any of you upgraded your power supply/converter? What do you recommend? The 45 amp has been discontented. Can you upgrade using the 55 amp? Our thermostat is a Duo-Therm analog by Dometic number 3107612.008 0212. It controls our furnace as well as the air conditioner and the fan, auto & speed. It appears to operate on 7.5 vdc? Do you have any experience with this unit. How do you check it out or troubleshoot? Is there a remote relay associated wit it? I have not found any relay associated with the furnace, only the ignition control board? Again, thanks for your help and advice!!! Best wishes to all for 2013Atwood RV Furnace will not start after changing propane cylI recently changed over to the reserve cylinder when I had the other 30 lb. propane cylinder refilled. Now my furnace, Atwood Hydro Flame 8531-IV-DCLP, will not start. When I turn it on, using the thermostat, nothing happens. The blower does not run as it normally did prior to the furnace lighting. I have tried switching cylinders. My Atwood Hot Water heater is working & I can use the Atwood propane range. I have 12.4 volts through the off/on switch & the circuit breaker. The fan will run if I jumper this to the motor. There is also 12 volts from the thermostat and the ground wires all check out. All web troubleshooting articles refer to a "relay" with four terminals. My unit does not have this, only the circuit board. Where is this relay? Also I get no light or flashes of the circuit board LED. Any and all help is greatly appreciated. Thanks!