got called out for no heat, and the control board appeared to be toast. contractors on the big wiring harness were scorched; the thing was an aftermarket board and not oem. after replacing the board with oem it is still throwing code for the pressure switch being stuck open. have tried jumping the switch to no avail, in spite of the fact that the switch is clearly open regardless. when testing the voltage on the board, it checks out up until the point of the thermostat wire. there is no voltage between C and R. tried reinstalling the other board and it throws a code for an open flame rollout switch. have tested all 4 of the high limit switches and tried jumping them as well. haven't even been able to get the inducer draft to come on. the blower motor kicks on and then throws the error code