The 33 and 13 error codes ndicate an open high temp limit error.
There may be
several limits on the furnace.Blow describes locations:
The pri***** *****mit control is located on the partition panel and monitors
heat exchanger compartment temperatures. It is a normally closed
(electrically), automatic reset, temperature-activated sensor.
The limit guards against the overheating as a result of insufficient
conditioned air passing over the heat exchanger.
The auxiliary limit control(s) are located on or near the circulator
blower and monitors heat exchanger compartment temperatures.
They are a normally-closed (electrically), manual-reset, temperature
activated sensors. These limits guard against overheating as a
result of insufficient conditioned air passing over the heat exchanger.
These would be located on the draft hood if you have one on your furnace.
The rollout limit controls are mounted on the burner/manifold assembly
and monitor the burner flame. They are normally-closed
(electrically), manual-reset, temperature-activated sensors. These
limits guard against burner flames not being properly drawn into the
Lets start with the most simple and easy. Look near burners for limits with a little button in center.It will push in to reset.If none are tripped we will go from here. Let me know if you have a multi meter for troubleshooting.