| Author | Message | ||
| Derek Pollard (207.194.162.3)
Rating: |
My suburban furnace just quit...blower works fine, but does not ignite...any ideas? I seem to remember something about a better board for this furnace. Any help appreciated. Derek | ||
| DaveD (206.47.98.151)
Rating: N/A |
A Dinosaur board is probably what you are thinking of. DaveD | ||
| Jim Stacy (12.87.108.152)
Rating: N/A |
Probably the board or the gas valve. The process is: 1 The thermostat closes contacts and starts a timer. 2 The timer times out and turns on the blower. 3 The blower air operates a sail switch to tell the board enough air is moving. This starts another timer. 4 The 2nd timer times out and the gas valve solenoid and electronic spark are operated simultaneously.The board senses the flame through the ignition electrode and runs the gas until the thermostat contacts open. 5 Gas is turned off and blower runs until furnace box is cool. The Dinosaur board is hardened and has retry ability. I did have a bad high voltage electrode. It would ignite the flame but didn't sense the heat and the flame would be turned off. That one took a while to figure out. The part looked great, but a new one fixed the problem. Jim Stacy | ||
| Stephen Fessenden (Sffess) (63.25.54.86)
Rating: N/A |
I remember reading about one couple that had continual problems with their furnace. After many board changes they finally checked the voltage and found that the voltage at the furnace was 11 volts through a fairly small wire. The factory told them that low voltage could cause boards to go bad. They increased wire size and had no more trouble. You might want to check voltage at the furnace with the blower running running while you are checking things out. Of course the couple had a factory RV with small wire. | ||
| GeorgeMyers (12.85.0.143)
Rating: N/A |
If the board is not functioning, there is an 80% chance that the problem is a cold solder on the board. If the circuit board is out of warrantee, it is worth the effort to carefully resolder each connection on the board because you have nothing to lose. The card probably will have to be replaced, but carefully check all of the inexpensive parts first. George Myers | ||
| daffycanuck (24.69.26.1) Rating: N/A |
I had much the same problem. Fan would run, but flame wouldn't light. Checked everything. This seemed to be an intermittent problem. So measured voltage etc. All o.k. Replaced board with Dinosaur board. This board has idiot lights which indicate when cycling etc. My problem seemed to disappear....I was happy until While parked on the desert one night our furnace would run, but not light. Checked idiot lights and all seemed to be running o.k., but no propane. My friend and I checked the sail switch and found it was not switching and a new switch made no difference. We started genset to bring voltage in batteries up and bingo, furnace would start. We discovered that when the voltage dropped a bit, the motor wouldn't turn fast enough to flip the sail switch. A battery test indicated batteries were no where near being depleted to point where nothing should work. (I forget what the voltage was) My friend had read where other people had the same problem and fixed it by increasing the 'sail' size on the sail switch. We cut a small piece from a beer can and epoxied it to the sail switch 'sail' increasing the size of it. That was two years ago and have never had a furnace failure since. I have kept in mind the sail switch was put there for a purpose. I purposely drained batteries to test function of sail switch....it still works properly. I wish I had made note of the voltages, but I didn't. I do know the new 'sail' is not much bigger than the factory 'sail', but just big enough to make the difference!! Works | ||
| Tom Caffrey (Pvcces) (12.146.33.167)
Rating: N/A |
We just completed a trip and found that the furnace would always quit before morning and always work at night. Guess when we charged our batteries? At night, before turning in. If we charged batteries in the morning, the furnace took right off. Our furnace does have a small lead, which I will be changing on our next trip! Thanks for all the comment on this subject. We have already bought a dino board, but I don't plan to install it until we have to remove the furnace because the furnace will take some work getting it out. Tom Caffrey PD4106-2576 | ||
| Tom Caffrey (Pvcces) (12.146.33.167)
Rating: N/A |
We just completed a trip and found that the furnace would always quit before morning and always work at night. Guess when we charged our batteries? At night, before turning in. If we charged batteries in the morning, the furnace took right off. Our furnace does have a small lead, which I will be changing on our next trip! Thanks for all the comment on this subject. We have already bought a dino board, but I don't plan to install it until we have to remove the furnace because the furnace will take some work getting it out. Tom Caffrey PD4106-2576 | ||
| DaveD (216.18.113.69)
Rating: N/A |
I found with the last motor home we had that the furnace wouldn't work off battery power - probably the same problem with too small a lead. It would work on shore power, but not consistently - usually if it did not relight, cycling the furnace "off" and then back "on" would work. Cleaning everything helped a bit, but I think the sail switch may have been where the problem was. DaveD |
