Ruud natural gas furnace occasionally will not turn on
About 15 yrs old, clean, yes some rust. Seems to run fine for a week, then will not turn on. Replaced electronic thermostat (but now know that was not the problem). Have removed thermostat and used jumpers to cause gas to open (flame, has pilot light) and use another jumper to start fan. But now that is not working consistently. Used multimeter and there is voltage with Red and White (gas) and Red and Yellow (blower). Is there a way to test the 3 sensors that are wired in a series? What is a typical - based on experience - cause… to help me to know where to start to look. Thanks!
I belive you are saying you have a standing pilot (IE: always lit) and upon a call for heat nothing happens. Is this correct? Then tell us what you have to do to get unit operating again. Also assuming your wires are color coded correct if you jump the R to Y you will be starting the outdoor a/c. R to G is the fan only.