21
Low Speed Fan Adjustment
2-Pin DIP Switch
The Low Speed 2-Pin DIP switch is located near the center of
the UCB. See Fig. 23.
When replacing UCB, the board will be shipped as default
without a low speed selected. For all 40RF units, set both dip
switches to “OFF” (0) for Test and Balance. Set both dip
switches to “ON” (1) for normal operation.See Table 11. The
dip switch positions can also be found on the unit's control
label diagram.
FAN FAULT DETECTION
The supply fan assembly is equipped with a relay internal to the
motor and a manual limit switch installed on the stator. These
components work in tandem to prevent the supply fan from run-
ning if the there are electrical issues or high temperatures in the
supply air section. If the 40RF is connected to the condensing unit
correctly (refer to Power Supply and Wiring), the Unit Control
Board will also prevent the thermostat signals from being sent to
the condensing unit, preventing compressor(s) from energizing if
there is a problem with the supply fan.
FREEZE PROTECTION
On select models, there is a factory-installed and wired tempera-
ture switch (P/N HH18HB016) to protect the compressor(s) in the
condensing unit when frost buildup is present on the indoor coil.
The temperature switch is used to prevent the compressor(s) from
turning on while the indoor coil is frosted. Refer to the unit wiring
label diagram for wiring of this switch.
Fig. 23 — UCB Fan Speed Controls
Table 11 — Low Speed 2-Pin DIP Switch Settings
LOW SPEED
% OF USER SET
FAN SPEED
MODE
DIP1 DIP2
0 0 100% Test and Balance
11 66% Normal Operation
Fan Speed Set Up Controls
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