Transformer - A.O. Smith BTH 120 Service And Parts Manual

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...
blue to ground does not have 24 VAC
blue to ground does have 24 VAC
yellow to ground does have 24 VAC
yellow ground does not have 24 VAC
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).
A. O. Smith Water Products Company
Irving, Texas 2000©
TROUBLESHOOTING
STEP 5 - 24 VAC FROM TRANSFORMER
Meter Should
Read 24 VAC
THEN
replace trans
continue
replace trans
go to Step 6.
STEP 6 - CONTROL BOARD TEST
22
Service Handbook
Training Department