suburban Heater woes in 19 degree weather

[cartercarbaficionado]

getting a little annoyed with this guy shutting its gas off randomly and not starting when told to unless I take the cover off and smack the metal line going in with a metal object, it will light everytime like that and was working well until a few weeks ago when the control board got a red light on that I couldn't see until today
things to note: this is a suburban ne34s, I'm not using the factory lpg tank because it's having issues (unhooked and empty for unknown amount of time) but I have a 5 gallon propane tank hooked up and it's working perfectly so far, I think it's a replacement board but not looking forward to ripping this Heater to check in this weather since it makes a massive hole for Cold air to enter my living space
if anyone has any ideas I'm up to try them but what I know so far is smacking the pipe is jostling the valves and all of my sensors in the Heater unit itself check out fine but I have no idea if the stock lpg tank tells the Heater it's empty or not

[piper guy]

If it’s the usual Suburban SF42 ( you didn’t tell us what model and year your coach is), the circuit board comes out in like 5 minutes if that. Pull the fuse for the thermostat on the inside panel before you go out to the furnace.

Take off the 4 screws holding the outside cover and the cover will pull off with both the intake and exhaust attached. If it doesn’t come off easily, then unscrew and remove them separately. Look at the top of the fan housing and you’ll see a silver bracket that is held on with two screws. Remove screws and work the bracket out and the circuit board is on top. If the board is toast, get a new one from Dinosaur Electronics.

[XCMARK]

if your using small tanks at 19*f you may have low pressure in the tank. you could try running a Y fitting and running multiple tanks to help with problem. You may also have a oil substance in the fuel lines causing low flow. You could have a regulator sticking also causing low pressure, next time it will not light try the stove top see if you have a normal flame on the big burner without hitting the lines.

[cartercarbaficionado]

Originally Posted by piper guy

If it’s the usual Suburban SF42 ( you didn’t tell us what model and year your coach is), the circuit board comes out in like 5 minutes if that. Pull the fuse for the thermostat on the inside panel before you go out to the furnace.

Take off the 4 screws holding the outside cover and the cover will pull off with both the intake and exhaust attached. If it doesn’t come off easily, then unscrew and remove them separately. Look at the top of the fan housing and you’ll see a silver bracket that is held on with two screws. Remove screws and work the bracket out and the circuit board is on top. If the board is toast, get a new one from Dinosaur Electronics.

I said what suburban furnace model it is, also its a 1987 winnebago superchief. but you'll find more information on the furnace model itself

[cartercarbaficionado]

Originally Posted by XCMARK

if your using small tanks at 19*f you may have low pressure in the tank. you could try running a Y fitting and running multiple tanks to help with problem. You may also have a oil substance in the fuel lines causing low flow. You could have a regulator sticking also causing low pressure, next time it will not light try the stove top see if you have a normal flame on the big burner without hitting the lines.

all burners are the same size, could be a sticking regulator and I think the copper lines are fairly clean since the water heater started with no issues (no water in unit just lit long enough to watch it ignite fully before shutting off) though I have full gas flow to the stove the whole time this is happening and my blower and sail switch are operating correctly