A.O. Smith BTH 120 Service Handbook - Troubleshooting
A. O. Smith Water Products Company
Service Handbook
Irving, Texas 2000©
Training Department
22
TROUBLESHOOTING
STEP 6. 24 VAC FROM CONTROL BOARD TERMINAL CN3 TO E.C.O.
Plug to CN 3 disconnected. (Energy Cutoff)
Check for 24 VAC red terminal 4 to ground on CN 3 terminal (red wires are the ECO wires).
STEP 6 - CONTROL BOARD TEST
STEP 5 - 24 VAC FROM TRANSFORMER
STEP 5. 24 VAC FROM TRANSFORMER
24 VAC transformer indicator light should be "on".
Insert probe into back of connect. Check for 24 VAC
blue wire connect to ground and yellow wire connect
to ground.
IF…
THEN
blue to ground does not have 24 VAC
replace trans
blue to ground does have 24 VAC
continue
yellow to ground does have 24 VAC
replace trans
yellow ground does not have 24 VAC
go to Step 6.
Meter Should
Read 24 VAC