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The blower motor is a true variable speed motor designed to deliver constant CFM. Constant CFM is
valid, up to 1600cfm, with total static pressure up to 0.7 in. w.c. Constant CFM is valid, up to 1200cfm,
with total static pressure up to 1.2 in. w.c.
Single Stage Thermostat
•
When the thermostat calls for cooling, the
thermostat circuit between R and G is
completed.
•
The normally open contacts close, causing
the indoor blower motor to operate.
•
The thermostat circuit between R and Y/Y2
is also completed; this circuit closes the
contactor in the outdoor fan motor.
•
For a heat pump, the thermostat circuits R
and O energizes the reversing valve,
switching it to the cooling position (depends
on outdoor HVAC unit).
•
The air handler blower will turn off 90
seconds (default) after the thermostat stops
calling for cooling.
NOTE
For single stage systems, do not use the Y1
terminal.
2 Stage Thermostat
•
First stage (low) cooling: Thermostat closes
circuits R to G, R to O, and R to Y1.
•
Unit delivers low stage cooling airflow.
•
Second stage (high) cooling: Thermostat clos-
es circuits R to G, R to O, R to Y1 and R to Y/
Y2.
•
Unit delivers high stage cooling airflow.
IMPORTANT
•
During installation, use caution to prevent
the control board and other controls from
getting wet.
36
Single Stage Thermostat
•
When the thermostat calls for heat, the
thermostat circuit between R and W2 is
completed, activating the hot water circulating
pump.
•
A time delay (5 seconds default) follows after
the thermostat circuit between R and G are
complete, activating the blower motor.
•
The air handler blower will turn off 120
seconds (default) after the thermostat stops
calling for heating.
2 Stage Thermostat
•
Thermostat closes circuit R to W1 or W2.
•
Unit delivers the selected heat airflow.
•
Unit delivers W1 or W2 heating airflow and
pump is exercised.
Continuous Fan
•
Thermostat closes circuit R to G.
•
Blower runs at continuous fan airflow.
The air handler has an included pump timer
feature. The pump timer activates the circulating
pump for one minute every twenty-four hours
(default) by completing the thermostat circuit
between R and W. The circulation frequency can
be adjusted in the controls of the air handler.
Canadian Air Handler Installation and Operation
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