A.O. Smith 120 trough 500 Service Handbook page 32

TROUBLESHOOTING THE EFFIKAL STYLE DAMPER (continued)
Condition:
Thermostat closed, damper is open fully
STEP A3
IF
24VAC is present
24VAC is not present
A.O. Smith Water Products
Irving, Texas ©2000
BTR TANK TYPE HEATERS
SERVICE HANDBOOK
TEST FOR 24VAC BETWEEN BLACK AND YELLOW
31
THEN
This is correct – continue to Step 11
•
See Step 9
•
Check the harness plug connecting ----
•
Check that cam on shaft rotates with
shaft
•
Replace the damper board
Service Handbook
Training Department