Furnace short cycling
Hi everyone,
First time posting but long time reader of these forums. Down to the brass tax here, I have a suburban sf 25 that cycles on the limit switch. I have not bench tested unit yet or checked WC pressure. I know there is not enough vents attached to furnace as the build quality on these RV's are sometimes well below par. If front cover of furnace is on it cycles on limit switch about every 3 to 4 minutes. With cover on the temp out of closest vent (about 3ft away) registers at about 166 degrees when limit switch activates. It runs the cool down cycle then fires back up and repeats process. With all vents off unit and front cover off, the burner chamber directly behind limit switch gets close to 170 then cycles as usual. If I jumper the limit switch the furnace will run non stop. However the temps of burner chamber are 230 after 12min of running with an exhaust temp of over 400. I have replaced limit switch twice so I know it is working correctly but I believe the furnace is being over fired and cannot dispel heat out fast enough. I will WC check my lp pressure to make sure it's at 11 ish but other then that I am at a loss. I checked the ohms of the dual solenoid gas valve on the furnace itself and I'm right at 38 so I am in the specs of 30 to 50 on both sides. Is there a way to adjust flame via the gas valve on the furnace itself? My heating cooling system is run via remote on a carrier V system. Can I remove the furnace from the carrier units thermostat via the wires spliced at back of furnace and splice in a digital wall mount one with no I'll effects? Any input is greatly appreciated. I will follow up with info after I check lp pressure.
Thank you.
First time posting but long time reader of these forums. Down to the brass tax here, I have a suburban sf 25 that cycles on the limit switch. I have not bench tested unit yet or checked WC pressure. I know there is not enough vents attached to furnace as the build quality on these RV's are sometimes well below par. If front cover of furnace is on it cycles on limit switch about every 3 to 4 minutes. With cover on the temp out of closest vent (about 3ft away) registers at about 166 degrees when limit switch activates. It runs the cool down cycle then fires back up and repeats process. With all vents off unit and front cover off, the burner chamber directly behind limit switch gets close to 170 then cycles as usual. If I jumper the limit switch the furnace will run non stop. However the temps of burner chamber are 230 after 12min of running with an exhaust temp of over 400. I have replaced limit switch twice so I know it is working correctly but I believe the furnace is being over fired and cannot dispel heat out fast enough. I will WC check my lp pressure to make sure it's at 11 ish but other then that I am at a loss. I checked the ohms of the dual solenoid gas valve on the furnace itself and I'm right at 38 so I am in the specs of 30 to 50 on both sides. Is there a way to adjust flame via the gas valve on the furnace itself? My heating cooling system is run via remote on a carrier V system. Can I remove the furnace from the carrier units thermostat via the wires spliced at back of furnace and splice in a digital wall mount one with no I'll effects? Any input is greatly appreciated. I will follow up with info after I check lp pressure.
Thank you.
