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Standard Dehumidification with FX4 Multi-tap ECM Fan Coils
For better dehumidification, the ACC+ terminal on the thermostat can be used to control
a speed tap when there is a No call for dehumidification. The G terminal will be used to
control a speed tap when there is a call for dehumidification. The ACC+ terminal will
need to be set up properly for dehumidification through the thermostat control screens.
NOTE
: Multi-Tap ECM motors have multiple speed taps that need to be set properly
when commissioning a system. It is the responsibility of the installation/service
technician to ensure the equipment is maintaining a minimum of 315 CFM per ton. See
the Fan Coil installation instructions for setting the speed taps correctly.
Set Up Standard Dehumidification on an FX4 Fan Coil
1) Connect the ACC+ terminal to the speed tap designed for cooling when there is
NO demand for dehumidification. Recommended minimum of 350 CFM/ton (i.e.
“Cooling speed” tap).
2)
The G terminal should be connected to the “Dehumidification speed” tap.
(Required Minimum of 315 CFM/ton)
For example: ACC+ will be set to active open and can be connected to speed tap
3. When there is no demand for dehumidification, then ACC+ will supply 24V to
tap 3 causing the motor to run at the tap 3 CFM. When there is a
dehumidification demand ACC+ will remove 24V from speed tap 3 and since G is
active already (in cooling) the Fancoil will run at the speed tap connected to G
likely speed tap 2 CFM.
NOTE
: on FX fan coils, when two speed taps are energized at once, the higher of
the two tap number is used. Therefore; when Y1/Y2 & G & ACC+ are energized
during a call for cooling, ACC+ is used.
Summary of Contents for TP-WEM01
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