A. O. Smith Water Products Company
Service Handbook
Irving, Texas 2000
©
Training Department
25
TROUBLESHOOTING
STEP 9 - BLOWER SPEED TEST
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.
IF…
AND
terminal 1 to gnd. does not show 120 VAC
terminal 1 to gnd. does show 120 VAC
blower is running
blower is not runn
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
He a te r m ode ls -
966 or 967
Ohm s re sista nce
de sire d +/- 7.5%
BTH 120
11.5
BTH 150 AND 199
11.2
BTH 250
7.4
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.
Summary of Contents for BTH 120
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