SBD TANK TYPE HEATERS
SERVICE HANDBOOK
Technical Training Department
Ashland City, TN ©2003
30
TROUBLESHOOTING THE EFFIKAL DAMPER (continued)
Condition:
Thermostat closed, damper is open fully
STEP 10A TEST FOR 24VAC BETWEEN BLACK AND YELLOW
NEHT FI
11 petS ot eunitnoc – tcerroc si sihT tneserp si CAV42
24VAC is not present • See Step 9B.
• Check the harness plug connecting.
• Check that cam on shaft rotates with
shaft.
• Replace the damper board.
• Ensure that cam is secure against end
switch.
Condition:
Damper rotates continuously
STEP 10B ADJUST END SWITCH TO CAM CONTACT
NEHT FI
Damper stops in proper position 24 VAC should be open on a call for heat
and close during standby/
Damper does not stop in proper position • Replace damper assembly.