York d1na036n07206a

[pmolina]

Every 10-15 seconds the heater surges as if it's trying to come on, even though it just went off and has reached its temp. Everytime it tries to kick on it blows air out of the exhaust vent(I guess:huh: its an exhaust vent).  We turn the thermostat off after it reached it's temp but wife is complaining she gets cold:crybaby:!

Ok so we had a H\A guy come out, but he said he could find nothing wrong??? It didnt do this last winter or summer but there's nothing wrong:huh:.  Oh he did say if there was some thing wrong it would have to be the contol module.  Oh and one more thing that is odd one by one we are losing heat to our rooms. :help:

[dkpd1581]

I know this is an old post but was looking through at the 0 replies....figured I would give it a try. Heat season is coming and most likely you will have the same problems again.  I couldn't pull up your furnace; however, a common problem with a furnace that comes on, runs fine, shuts off, and then has the blower motor come back on for a short period of time and then mysteriously stops is the Temperature Limit Switch in the burner compartment.

You may have a Combination Fan Limit Switch

http://americanhvacparts.com/Merchant2/merchant.mvc?

The heater turns off and the burner compartment temperature still continues to rise (for several reasons).  The limit switch senses this temperature rise and attempts to cool the system down by coming back on and moving air through the exchanger for a period of time.  This could be due to a defective limit switch, and improperly adjusted switch, a dirty filter, obstructed exchanger, obstructed flue, kinked/defective duct work., to short of a FAN OFF cycle adjustment, blower motor speed too slow creating too high of a temperature rise in the exchanger, defective blower motor, defective induced draft motor.

I have even had a blower motor mysteriously come on and blow hot air in the summer time at a Church in Clarkston GA.  The air handler was on a second floor in a mechanical closet where the indoor temperature in the closet met/exceeded the minimum OFF setting of the Combination Fan Limit Switch - the Church saved money by not running the AC and things got hot.  The heat was enough to engage the furnace safety switch even in the dead of summer when a thermostat call for heating was the furthest from anyone's mind - ven with the thermostat in the OFF position.

Your primary issue most likely lies in the safety switch:

1. Identify which style safety/limit switch your unit uses

2. Check it for adjustment/calibration/operation

3. Check and adjust the heat rise across your exchanger and adjust as necessary

4. Verify indoor blower motor speed and operation

5. Verify no flue or heat exchanger obstructions

6. Verify during the on cycle that you have no flame roll out or blow back in the burner compartment

Best of luck and let us know

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