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240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
12-15. Manually adjusting the fan motor speed
Only
540 (T-H3)models
While the FM+ DIPswitch will automatically increase the fan speed by 6%, the fan motor speed on
the 540 (T-H3) models can also be manually adjusted. In order to perform manual adjustments to the
speed, a controller is required.
Adjusting maximum fan motor speed
1. While water heater is in operation, set DIPswitch No.7 on the upper bank of the 540 (T-H3)
computer board to the “ON” position. (Fig. 1)
2. On the controller, display mode #3 (fan motor speed) by entering the “Diagnostics mode” (Refer to
Section 12-1).
3. Press and hold down the
“MAX”
button on the computer board. While holding down the “MAX”
button, press either the
“Increase”
or
“Decrease”
button to increase or decrease the fan motor
speed, respectively (Fig. 2). Refer to the controller display to verify that speed has been set to
desired value.
4. After fan speed has been set, set DIPswitch No.7 on the upper bank of the 540 (T-H3) computer
board back to the “OFF” position.
Adjusting minimum fan motor speed
1. While water heater is in operation, set DIPswitch No.7 on the upper bank of the 540 (T-H3)
computer boardto the “ON” position. (Fig. 1)
2. On the controller, display mode #3 (fan motor speed) by entering the “Diagnostics mode” (Refer to
Section 12-1).
3. Press and hold down the
“MIN”
button on the computer board. While holding down the “MIN”
button, press either the
“Increase”
or
“Decrease”
button to increase or decrease the fan motor
speed, respectively (Fig. 2). Refer to the controller display to verify that speed has been set to
desired value.
4. After fan speed has been set, set DIPswitch No.7 on the upper bank of the 540 (T-H3) computer
board back to the “OFF” position.
WARNING
Manually adjusting the fan motor speed of the 540
(T-H3) models will change the
amount of intake air for combustion, which can cause excess CO emission from
the exhaust chamber if the fan motor speed is set incorrectly. Therefore, this
procedure should never be performed unless the Technical Services Department
has given consent and authorization.
The dark square is the direction
the DIPswitch should be set to.
OFF
ON
1 2 3 4 5 6 7 8
DIPswitch setting on the 540 (T-H3) models
(Upper bank of DIPswitches)
540 (T-H3) models
computer board
MIN button
MAX button
Increase button
Decrease button