A.O. Smith 120 trough 500 - Manual (Page 33)

BTR TANK TYPE HEATERS
SERVICE HANDBOOK
A.O. Smith Water Products Service Handbook
Irving, Texas ©2000 Training Department
32
STEP 11 WIRE HARNESS TEST
STEP 11. WIRE HARNESS TEST. Test for 24 VAC between terminal 24V on the IID
module, and 24V (GND).
IF THEN
24 VAC is not present: • Check the wiring harness.
24 VAC is present: • Go to step 12.
Note: This test may be easier to conduct by removing the red wire from the IID terminal. Test for 24
VAC between the red wire and ground. Reconnect the red wire to the 24V terminal after the test.