[sparko]

Carrier 58 DHC gas heater (“crusader” on access door) 1992.

The heater goes through the start up sequence:
Honeywell Thermostat calls for heat; the draft inducer starts; the igniter glows and the burners light. After about 45 seconds, the blower starts for about 2 seconds and the burners go out and everything shuts down. Sequence starts again. Sometimes the blower will go for 1 or 2 minutes before shutting down. Room temp never reaches thermostat setting.

I tested the sequence by touching S1 and S2 terminals on the control board as directed and the heater goes through the test sequence as it is supposed to, including low speed blower and high speed blower.

Sometimes the blower will start on it's own (no draft inducer or flames) for 1 or 2 seconds and shut off. Then it will try to start again and may run a few seconds and stop. I hear the click, click of the blower switch.

The blower seems to go on and off at the wrong times, and sometimes just gives a “puff” and shuts down, then I hear the draft inducer starting the sequence over again.
What's wrong? Control board?