State Industries SBD85 500 - Manual (Page 24)

SBD TANK TYPE HEATERS
SERVICE HANDBOOK
Technical Training Department
Ashland City, TN ©2003
23
STEP 6 PC BOARD MOTOR TEST
STEP 6. PC BOARD/MOTOR TEST. Check for 24 VAC between the two motor lead
terminals of the PC board. Disconnect the wires for this test.
IF THEN
24 VAC is not present:
•
Replace the Damper Drive (part #
194484) and go to step 7. The board
and relay are one piece. Regardless of
which part is defective, both parts
should be changed.
Voltage is present: • This verifies that the motor is receiving
power but not closing the damper.
• Replace the Damper Drive and go to
step 7.
Note: The service switch may be used to bypass the damper, while waiting for a replacement part.
WARNING - In the event of damper motor failure, verify that the damper is in the "open"
position before utilizing the service switch
Service Switch
Motor Lead Motor Lead