11.
12.
If outdoorairtemperatureor pressureat suction
valve changes,chargeto new suction line
temperatureindicatedonchart.
Optimum performance will be achieved when
the operating charge produces 5° to 6°F
suction superheat at suction service valve
with 82°F (28°C) outdoor ambient and 80°F
(27°C) dry bulb (67°F / 19°C) wet bulb) indoor
temperature (DOE "B" test conditions) at rated
airflow.
C. HEATING MODE
To check system operation during heating cycle, refer to
the Tech Label on outdoor unit. This chart indicates
whether a correct relationship exists between system
operating pressure and air temperature entering indoor
and outdoor units. If pressure and temperature do not
match on chart, system refrigerant charge may not be
correct. Do not use chart to adjust refrigerant charge.
NOTE: When charging is necessary during heating
season, charge must be weighed in accordance with unit
rating plate +0.6 ounces per foot of a inch liquid line above
or below 15 feet respectively (+17g per 305mm of 10mm
liquid line above or below 4.6m respectively).
SEQUENCE OF OPERATION
A. COOLING MODE
On a call for cooling, the thermostat makes circuits R-O,
R-Y, and R-G. Circuit R-O energizes reversing valve,
switching it to cooling position. Circuit R-Y energizes
contactor, starting outdoor fan motor and compressor.
Circuit R-G energizes indoor unit blower relay, starting
indoor blower motor.
When thermostat is satisfied, its contacts open,
de-energizing contactor and blower relay. Compressor
and motors stop.
NOTE: If indoor unit is equipped with a time-delay relay
circuit, the blower runs an additional length of time to
increase system efficiency. (Applies to both cooling and
heating modes.)
B. HEATING MODE
On a call for heating, the thermostat makes circuits R-Y
and R-G (circuit R-O is NOT made, and the reversing
valve stays in the de-energized, heating position). Circuit
R-Y energizes contactor, starting outdoor fan motor and
compressor. Circuit R-G energizes indoor blower relay,
starting blower motor. If the room temperature continues
to fall, circuit R-W2 is made through the second-stage
room thermostat bulb. Circuit R-W2 energizes a
sequencer, bringing on the first bank supplemental
electric heat and providing electrical potential to the
second heater sequencer (if used). If outdoor
temperature falls below the setting of the outdoor
thermostat (field-installed option), contacts close to
complete the circuit and bring on the second bank of
supplemental electric heat.
When the thermostat is satisfied, its contacts open,
de-energizing contactor, blower relay, and sequencer.
Compressor, motors, and heaters stop.
12 specificationssubjectto change without notice. 428 01 5106 03
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