45K BTU garage/shop heater. POS from day 1. I have replaced the ignitor, now after reading the book(AGAIN) the 4 flashes indicates that either my Roll Out Switch or Hi Limit Switch need to be reset - my question is this. What type/amount of resistance should I measure on these two switches to determine they are bad or good. Right now if I stick the fluke meter on I get nothing. On the FRS I get noting in either position. Very frustrating. For 6 years, every year I fight with this thing.

The switch is 100% open or 100% closed. Touch the leads of your meter together to test the leads and meter before doing a ohm test (your checking to make sure your meter can check for true resistance).

I have checked my meter and it is working correctly. I have also cycled the FRS and get nothing in either position. YOu might have guessed that at this point I am gun shy about spending any money on this thing as I have already paid for two service visits and have the same mess I had before. If I buy the FRS - which by the way works very quickly when I hold a lighter up to it, how can I be sure this will fixt it. I know short answer you can't be. As a quick test can I jumper both the Hi Limit and FRS to see? I have to think the Hi Limit is way lower in the ladder logic as it would only come into play after the burners ignite. Yes I have checek, with a manominer(sp) and have 12WC on the outlet side of my tank valve, 12WC at the inlet side of the gas valve and I can't get anything at the outlet side of the valve becuause it won't run through the cycle. Incidentally the large blower fan does kick on as though the burners had ignited. Seems odd since the logic did not play out a la ignited burners - what is the need for the fan if the burners don't ignite.