A.O. Smith 120 trough 500

BTR TANK TYPE HEATERS

SERVICE HANDBOOK

A.O. Smith Water Products Service Handbook

HARNESS CHART

Heater Harness Function Damper Harness

Black 24V Hot 1-Brown

Yellow 24V from Therm 2-Orange

Red 24V from damper 3-Yellow

White 24V common 4-Black

Series 110 and 111 heaters and converted model BTR(C) and BTC heaters with Effikal

Dampers.

NORMAL OPERATION

Condition:

• Heater on standby

• Damper closed

• High Limit closed

STEP A

TEST FOR 24VAC BETWEEN BLACK (COMMON)

AND BROWN

STEP A. TEST FOR 24VAC BETWEEN BLACK (COMMON) AND BROWN

IF THEN

24VAC is present Continue to Step B.

24VAC is not present See Troubleshooting Step A1

Wires are from left to right:

Black iYellow iBrown iWhite