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

Reconnect plugs to board.
Blower operation check
• Tank must be calling for heat (minimum setting available is 80 F)
• Set multimeter to read 120 VAC
STEP 9. Check for 120 VAC from the back of CN 2 plug term 1 (black) to ground and from CN 2
term 2 (white) to ground.
He a te r m ode ls -
966 or 967
BTH 120
BTH 150 AND 199
BTH 250
Note: A shorted blower motor may damage the
control board or, on BTH 250 models, the blower
speed reduction board. Conduct a continuity
check between the black and white terminals of the
C2 blower plug.
IF...
terminal 1 to gnd. does not show 120 VAC
terminal 1 to gnd. does show 120 VAC
A. O. Smith Water Products Company
©
Irving, Texas 2000
TROUBLESHOOTING
STEP 9 - BLOWER SPEED TEST
Ohm s re sista nce
de sire d +/- 7.5%
11.5
11.2
7.4
AND
blower is not runn
blower is running
25
Service Handbook
Training Department