[ronald871]

ALL i get is the fan motor blowing nothing else code 33 i check the 2 resetable limit switch with the red wires for a open both were fine when i remove 1 of the thermistat wire off the control board the code will clear and then place wire back on with power the inducder will start and heater will go threw it's normal cycle till it call 4 gas then i get the code 34 and the inginator will light 2 times before going on lockup bad board? can that cause a code 33? as the heater say's limit switch but obvious the board feed the limit switch

[mark28]

the high limit switch on the right hand upper side in the firewall is more then likely bad. its not a re-settable switch, how ever you could jump the two red wires together for trouble shooting. more then likely your secondary heat exchanger is plugged up and the furnace can not pull the flame through accordingly. remember to ask yourself why this switch is went out, because the furnace is getting too hot and can not get ride of its heat.