Carrier Gas Furnace, burner shuts off stating error code 33 and/or 13

[FrankMTL]

I have a Carrier Gas unit 9300TS model 58MTA100. It is combined with a multizone system as well as a Heat Pump. The system works great on the heatpump but as soon as it goes on EM HEAT and runs on the gas furnace, it works for about 10-15 minutes than the burner shuts off and the board gives me error 33 and/or 13. Which seems to mean limit switch error... I tried by passing the limit switch and it seems to work ok. I am thinking of replacing the limit switch HH12ZB190 (190 Degree)? Any suggestions, will this fix the problem?

[HayZee518]

is the high limit adjustable? if so try lowering the high set point a tad and trying it. if you have a multimeter, check the switch on the lowest resistance range for continuity - if it reads open replace it.

[06stang]

You should never bypass a limit switch unless you are prepared to sit there and monitor. These safety swithch are there for a reason. Having said that, if you have a restriced air flow, dirty filter, evaporator or under sized/ closed ducts and it has tripped the hi limit on several occasion the value (temperature trip point) will change as the bimetal strip has become weak. Limit switchs are inexpensive and should be changed with the same value swich as the original. Another issue that can cause this error code is the burner over firing. Has the gas pressure been checked? At sea level you should have 3.5" wc as you raise above sea level this will change. Over firing will cause the heat exchange to be too hot and in time will burn a hole in it causing CO to accumulate in the home. Again a very dangerous issue. If changing the limit doesn't solve the issue have a proffessional troubleshoot and repair for you.