When i turn my thermostat on the heat element and the vent motor turns on at the same time and it starts blowing hot air. this only lasts about 5-10 min until the heating element shuts off and it blows cold air for the rest of the time. It doesn't stop because it reached the temperature it was supposed to because my house stays cold all the time and i would like my heater to stay on. Any assistance would help? Thank you!
It sounds to me that your air flow is restricted somewhere. The first thing to check is your air filter. If that gets real dirty your restricted air flow will cause the hi-limit(hi temperature limit switch) in your heat exchanger compartment to over heat and open up your gas valve electrical circuit,thus, shutting off the gas to your burners. After the hi-limit switch cools down the furnace will go back to heating again then it will overheat again(you get the picture?) If it keeps cycling on and off like that the house will never get warm if it is cold outside. If your air filter is reasonably clean(you should be able to see light thru it easily) then the secondary heat exchanger could also be dirty, this is located above the indoor fan housing, you would need to pull the indoor blower assembly out of the furnace and look up above. The secondary heat exchanger looks similar to a radiator will fins. You can use a medium stiff plastic brush to brush the dirt,hair, whatever off of it. Another problem spot would be the cooling evaporator coil (if you have central airconditioning) located most likely above the furnace in the plenum(if your furnace is in a basement). This usually is difficult to access if an access cover wasn't installed when the airconditioning was installed. I would recommend an experience service tech to clean it for you. Also make sure all you supply air registers and return air registers are open . These are the things I would check first. Good luck!!
This sounds to be a possible deffective fan limiting switch. It over rides everything if it thinks the heater is overheating,shutting off the gas and running continuously. You can pick up a fan limiting switch at a heating and air conditioning supply. You need to locate and take the old one with you.
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