RV Repair: Suburban furnace wont heat, suburban water heater, suburban furnace

Question
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Thanks for the help.  I finally took the furnace in to have it bench tested and they also checked the circuit board.  Turns out the problem was with the thermostat.  

Followup To
Question -
I have a suburban SF-42 furnace in my '97 Safari Trek, model 2430

The furnace blows cold air.

I am pretty mechanically inclined, and not bothered by tearing into my furnace to get it  working.

I removed it from its installed position.  When I activate the thermostat, the furnace starts blowing cold air, just as it did before I removed it.  I probed the red wire leading to the board and there was voltage there. I could hear the LP valve clicking in after a short delay.  So it appears to me that the board, electrode or aperture could be the problem.  I removed the inspection plate so I could see the ignitor and aperture.  I saw nothing unusual there.  I think I may have to replace either the board or the igniter.
I have a board out of a Suburban water heater that I just replaced and am thinking that this board will probaly work, even though it isn't the same size.  How do I test board and how do I test the igniter?

Answer -
Ron,
   The circuit board you recently replaced is probably a 520741.  Depending on your serial # for SF 42 it may be the right one.  FOR SERIAL #'S 912000061 & BELOW USE 520612
FOR SERIAL #'S 912000061 TO 003805481 USE 520741
FOR SERIAL #'S 003805481 & ABOVE USE 520820.  The only way to really test the circuit board is with a board tester.  You said it is getting 12 volts to the board, so you can check to see if it sends out 12 volts to the gas valve.  If it does and you can hear the valve click isolate the solenoids on the valve and make sure they are each clicking.  If they are then you can check for spark by removing the spark lead from the board and holding it approx. 1/8" from where it hooks up and look for a spark there.  I hope this helps.

Darren

Answer
Ron,
    I don't see how the problem could have been with the t-stat since it's only function is to tell the blower to come on.  Once that happens and the fan sets the sail switch it should send power to the circuit board through a limit switch.  Then the board opens the gas valve and provides an igniton source.  You said you had power at the circuit board.  As long as it was 10.5-14 volts it should have worked fine.  If you can explain further let me know, I'm not afraid to learn something new.  Thanks.

Darren