heater short cycling

peaches

Gas heater is short cycling... blows cold air.  Can turn it up to 80 and it will eventually catch up and heat to that temp but once you turn it down it starts again.  Had three professionals come check it last year and could not solve problem.  They suggested it might be the heat sensor.  What trouble shooting can I do to solve myself.  Thermostat works fine with the a/c.  Filter is clean.

Please help... we're freezing!!! :)

Tim McElwain

What is the make

of the heater? Does it have a pilot? If so is it electric ignition?



How many returns do you have coming back to the unit, assuming this is a forced warm air unit?

peaches

make of heater

the heater is a gibson.  I don't know if it is electric ignition... how can i tell?

There are 4 returns in the house.  When it short cycles the pilot light is on and then when the blower comes on the pilot light goes out.  Hope this helps and thanks for your response.

Tim McElwain

If it is spark ignition

the pilot will be out until there is a call for heat. You will hear a sparking sound and then the pilot will light, next the burner will come on and then in 30 to 60 seconds later the blower should come on.



If it is a hot surface igniter system when it calls for heat the igniter will start to glow and will take about 30 seconds or so and then it will ignite the burners?



If the pilot is lit all the time then it probably has a thermocouple type pilot system.