422 fan stays on

[woodauger]

The circulation fan runs at a very slow speed so long as the heater is plugged in, even when switched to 'off' and cold. The speed is obviously slower than either of the heater's design speeds. The connector wires at the board measure yel/red 108vac, yel/blk 62.5vac, red/ blk 41.5vac. when the fan is malfunctioning. The Problem occurs weather the thermostat is connected or not. the service manuals I have seen don't have the schematic for the 422, but show one for the 441 only. Does this sound like the board is in trouble? Thanks, Gary

[hawkins111]

If the red and black shows 42 volts I would think the main board relay is stuck on some how. You can have the board repaired for a reasonable price. Search on the net for Monitor circuit board repair and you will find the guy that can help.