Installation manual

ENVISION AIR HANDLER INSTALLATION MANUAL

ECM Blower Control

The ECM blower motor is controlled by an interface board

installed in the air handler and allows field selectable CFM

settings. The interface board receives inputs from the

thermostat and converts them to signals used by the ECM

motor. There are four different airflow settings that are field

selectable via DIP switches (see Blower Performance table).

Cooling/Heating settings

The cooling/heating CFM settings determine the

normal cooling/heating CFM when the unit is not in

dehumidification mode or auxiliary heat mode. DIP switches

1 and 2 ‘off’ is the lowest CFM setting while with DIP

switches 1 and 2 ‘on’ is the highest CFM setting. To prevent

air coil freeze up, the lowest CFM setting can not be used

when dehumidification mode is selected. DIP 9 must be ‘on’

to enable normal airflow settings.

Dehumidification Mode settings

This setting provides for field selection of humidity control

(via setting DIP 9 ‘off’). The cooling airflow settings are

determined by the Cooling/Heating DIP switch settings

above. Dehumidification mode reduces the selected normal

cooling CFM by 15%-20% which increases the moisture

removing capability of the heat pump. To prevent air coil

freeze up, the lowest CFM setting can not be used when

dehumidification mode is selected.

Dehumidification Mode (Continuous) – This mode is

selected via setting DIP 9 ‘off’ on the ECM interface board

and will be engaged whenever an ‘O’ input is present. In this

mode any time the unit is operating in cooling mode, it will

run at a CFM level 15%-20% lower than the selected normal

cooling CFM.

NOTE: Do not select dehumidification mode if the lowest

Cooling/Heating airflow level is selected (DIPS 1 & 2 off).

Auxiliary Heat settings - DIP 5 and 6 on the ECM interface

board are used to select the desired CFM in auxiliary/

emergency heat mode. Whenever auxiliary or emergency

electric heat is energized this air flow setting will be used.

NOTE: DIP switches 3, 4, 7, 8, and 10 are not used.