furnace gremlins ????

[donnyman]

Here I go again, I have everything needed for this unit to work, gas flow, ignition, new fan motor and sail switch, clean burner assembly.

I just reinstalled this unit so all has been gone over, several attempts were made to start with no luck. I need new ideas as to what is wrong. please help.

the furnace is a Atwood 8535-1v.


DONNY

[Pigman1]

Have you checked the LP gas pressure at the heater?

[donnyman]

Pigman

Hello! I haven't checked lP pressure but I did check my house battery voltage and man was it low 10v it is on charge as I type.

All Troubleshoot charts say low voltage will cause just the problem I am having, so, we will see but it may take all night.

If that is my problem I will be very happy except now I need to know why my battery which is quite new is so low!!!!!

this money pit is killing my wallet!

[wa8yxm]

Easy check of LP pressure ... Do other LP things work normally? The harder check requires test insturments.

Yes, 10 volts will do it. Fan does not spin fast enough to close sail swich.

If you have the service manual your multi-meter is your friend.

The furnace I know best is an ATTWOOD but some Su4rburans... Use the same control board (With a different paint job).

On this there is a multi-pin MOLEX connector, This is a tarnished memory but I think there are six pins.

The service manual will tell you the meaning of each pin, I THINK but am not sure one is ground (Else you pick a good ground point for the black (negative) lead on your multi meter.

ONE of the pins is "Sail switch"

Stick the red probe down into the "Back" (Wire side) of the socket till ti makes contact.. If you do not see any voltage, ever, the battery is the culprit. Not enough blower RPM due to low voltage. (This assumes switch is known to be good, bad switch (Damaged during install) may do it too.

[donnyman]

Hello!

Every thing is tested and functional! I even have a spark in the furnace but I fear it is too weak to do the job. my battery is dead even after a all night charge. I will replace it shortly then test the furnace again.

The battery is less than a year old so I think I have a charging problem.

it's raining so I have to wait but I will respond after I install another battery.

Thanks!!!

[donnyman]

I am a bit embarrassed to say the obvious isn't always, to me!

As I said everything was working but no ignition right? well while testing the ignition by arcing the high tension lead to ground it appeared to me if it was working so well why no flame (the obvious) "check the electrodes". so I turned the propane off at the tank.

pulled the gas valve assembly out and turned it around and grounded it to the frame and turned on the furnace ----no spark then I pulled the high tension lead off and tried it again. it arced to the frame. I got a "new set of electrodes" problem solved. the furnace fired the first try when reinstalled.

This is only part of the story...just let me say, don't buy cheap tools (voltmeter) my battery is fine.... whole other story.

Thanks for responding it really helps this old brain of mine.

DONNY