BTR TANK TYPE HEATERS
SERVICE HANDBOOK
A.O. Smith Water Products Service Handbook
Irving, Texas ©2000 Training Department
21
STEP 3 TEST HIGH LIMIT RIGHT TERMINAL
STEP 3. TO TEST HIGH LIMIT RIGHT TERMINAL. Ensure that the jumper wire
between the high limit and thermostat is connected, and the damper motor power line is
connected. Test for 24 VAC between the high limit right terminal and ground.
IF THEN
The meter does not read 24 VAC: • Push the reset button and redo the test (storage
water temperature below 185 degrees).
The meter reads 24 VAC: • Go to step 4.
After Push in Reset - 24 VAC is now present
Reasons For Resetting
Condition Cause Solution
High limit open Never set on initial
installation
Push high limit button
Excessive water temperature Faultythermostat Replace dual control
Heater shut down before
reaching thermostat setting
Faulty high limit Replace dual control
Note: The right terminal of the high limit has a jumper wire connected to the left terminal of the
thermostat. There is also a black wire connecting to the damper motor assembly. This black wire
supplies power to the motor to close the damper during periods of standby.