11
4. If the system is over charged, recover liquid refrigerant
slowly from the charging port on the liquid line from the air
handler until the float is in the middle of the sight glass.
5. Let the system run for at least 30 minutes. Make sure the
float is still in the middle of the sight glass. If the float is not
in the middle, repeat steps 3, 4, & 5.
system check
After R-410A is charged to the middle of the sight glass (in
heating), the discharge and suction pressure may be measured
to make sure that the system is operating normally.
• The discharge pressure should be between 300 – 350 psig.
• The suction pressure should be between 100 – 150 psig.
During the summer, after charging in heating mode, the
system should be shifted to cooling mode operation. Since
the system just ran in heating mode, the well will be cold. The
system discharge pressure is usually below 300 psig and the
suction pressure is usually below 100 psig. As time passes,
the well will gradually heat up and both the discharge and
suction pressure will increase. In a hot summer, the discharge
pressure could reach 400 psig and the suction pressure could
exceed 140 psig.
If an unknown or unidentifiable restriction is observed between
the high compressor discharge psig and low compressor
suction psig, check the entering and exiting temperature at
the oil separator.
notE:
The oil separator has a glass filter,
which may have become clogged. The pressure drop across
the oil separator should be no more than 5 psig. See Table 6.
Air Circulation - Indoor Blower
1. Set the thermostat system mode on OFF and the fan mode
to ON.
2. Verify the blower runs continuously. Check the air delivery
at the supply registers and adjust register openings for
balanced air distribution. If insufficient air is detected,
examine ductwork for leaks or obstructions.
3. Set the thermostat fan mode to AUTO and verify the blower
stops running.
System Heating
1. Set the thermostat’s system mode to HEAT and the fan
mode to AUTO.
2. Gradually adjust the thermostat temperature setpoint above
room temperature and verify that the compressor unit and
the indoor blower energize.
oPEratInG sEQuEncE
cooling
1. After receiving a
Y1
and
o
input the system will begin cooling
operation
2. Prior to compressor start, discharge pressure and suction
pressure are checked by the system control.
a. If the discharge pressure is above 635 psig, the system
will not start.
b. If the suction pressure is below 20 psig, the system will
not start.
c. If any temperature sensor is shorted or open, the system
will not start.
d. If any pressure sensor is open, the system will not start.
e. If the system has run in the previous 5 minutes, a 5
minute anti-short cycle timer must expire before the
system will restart.
3. If the above conditions are met the compressor will start
and the reversing valve shift into position if not already in
the cooling position
a. At any time during compressor operation the system
will stop if:
– The discharge pressure exceeds 635 psig.
– The suction pressure falls below 25 psig after 1
minute of compressor operation.
– Any temperature sensor becomes shorted or open.
– Any pressure sensor becomes open.
– The
o
input is removed.
– The
Y1
input is removed.
b. If the suction pressure is below 95 psig, the hot gas
injection valve will be opened for 10 seconds every 3
minutes until the suction pressure is above 95 psig. If
this continues for 60 hot gas injection activations, the
system will go into soft lock out mode (
SL
) for 60 minutes
for
status and event codes.
c. While the compressor is operating in cooling mode the
EXV attempts to control the superheat at the compressor
inlet to 7° F +/- 3° F. The EXV fully closes when the
Y1
input is removed.
heating
1. After receiving a
Y1
input (with no O) the system will begin
heating operation
2. Prior to compressor start discharge pressure and suction
pressure are checked.
a. If the discharge pressure is above 635 psig the system
will not start
b. If the suction pressure is below 20 psig the system will
not start
c. If any temperature sensor is shorted or open, the system
will not start.
d. If any pressure sensor is open, the system will not start.
e. If the system has run in the previous 5 minutes, a 5
minute anti-short cycle timer must expire before the
system will restart
3. If the above conditions are met the compressor will start
and the reversing valve shift into position if not already in
the heating position.
a. On units equipped with a Well Seal Valve, the valve will
open 5 seconds prior to compressor start.
b. At any time during compressor operation the system
will stop if:
– The discharge pressure exceeds 635 psig.
– The suction pressure falls below 25 psig after 1
minute of compressor operation.
– Any temperature sensor becomes shorted or open.
– Any pressure sensor becomes open.
– The
o
input is activated.
– The
Y1
input is removed.
c. After 1 minute of operation if the suction pressure
exceeds 236 psig or the discharge pressure 600 psig,
the system will stop for 30 minutes to allow well recovery
and code 09 or 10 will appear in the two digit display.
d. If at any time during heating operation the compressor
is prevented from running due to one of the above
conditions the
W2
output will be energized.
e. When the system is operating in heating mode the EXV
moves to control the discharge pressure between 300
and 346 psig. The EXV fully closes when
Y1
is removed.
