Unit Operation; Unit Start-Up; Operating Manifold Gauge Set And Service Valves - Lennox Elite EL22XPV Series Installation Instructions Manual

When the Operation Mode jumper is installed in the "Com-
fort Mode" the suction pressure setpoint is 125 psig.

Unit Operation

EL22XPV Unit Operation with a S30 Communicating
Thermostat
When the EL22XPV unit is installed with a S30 commu-
nicating thermostat and a communicating indoor unit, the
unit capacity will be controlled in the variable capacity
mode throughout the range of capacity from minimum ca-
pacity to maximum capacity based upon thermostat de-
mand. The indoor air volume will be controlled to match
cooling capacity throughout the capacity range.
EL22XPV Unit Operation with a Conventional 24VAC
Non-Communicating 2-Stage Thermostat
When the EL22XPV unit is installed with a conventional
24VAC non-communicating 2-stage thermostat, a Y1 first
stage heating or cooling demand will initiate heating or
cooling operation and first stage indoor blower operation.
The compressor will be controlled in the variable capacity
mode by varying the compressor capacity to obtain the
target suction pressure set point. The Y2 second stage
heating or cooling demand will initiate second stage blow-
er operation. Increased air volume will increase the load
on the indoor coil and increase the suction pressure. The
EL22XPV compressor capacity will continue to be con-
trolled based upon the suction pressure. The unit capacity
will be controlled in the variable capacity mode throughout
the range of capacity from minimum capacity to maximum
capacity. If the Y2 demand remains after 20 minutes, the
EL22XPV control will begin to ramp up the compressor ca-
pacity until maximum capacity is achieved. The EL22XPV
unit will cycle off once the thermostat demand is satisfied.
EL22XPV Unit Operation with a Conventional 24VAC
Non-Communicating Single-Stage Thermostat
When the EL22XPV unit is installed with a conventional
24VAC non-communicating single-stage thermostat, a Y1
first stage heating or cooling demand will initiate heating
or cooling operation and heating or cooling indoor blower
operation. In single stage thermostat applications, a jump-
er must be installed between Y1 and Y2 on the EL22XPV
outdoor control. The compressor will be controlled in the
variable capacity mode by varying the compressor capac-
ity to obtain the target suction pressure set point. If the
heating or cooling demand remains after 20 minutes, the
EL22XPV control will begin to ramp up the compressor ca-
pacity until maximum capacity is achieved. The EL22XPV
unit will cycle off once the thermostat demand is satisfied.

UNIT START-UP

IMPORTANT
If unit is equipped with a crankcase heater, it should
be energized 24 hours before unit start-up to prevent
compressor damage as a result of slugging.
1 - Rotate fan to check for binding.
2 - Inspect all factory- and field-installed wiring for
loose connections.
3 - After evacuation is complete, open the liquid line and
vapor line service valve stems to release the refrigerant
charge (contained in outdoor unit) into the system.
4 - Replace the stem caps and tighten to the value
listed in table 2.
5 - Check voltage supply at the disconnect switch. The
voltage must be within the range listed on the unit's
nameplate. If not, do not start the equipment until
you have consulted with the power company and
the voltage condition has been corrected.
6 - Connect manifold gauge set for testing and charging.
7 - Set the thermostat for a cooling demand. Turn
on power to the indoor indoor unit and close the
outdoor unit disconnect switch to start the unit.
8 - Recheck voltage while the unit is running. Power
must be within range shown on the unit nameplate.
9 - Check system for sufficient refrigerant using the
procedures outlined under Checking Refrigerant
Charge.
HEAT PUMP CONTROL – DEFROST OPERATION
A full description of the heat pump control can be found
in the detailed installation and service procedure manual
available on LennoxPros.com.
The master control measures differential temperatures
to detect when the system is performing poorly because
of frost build-up on the outdoor coil. The heat pump con-
trol self-calibrates when the defrost system starts and
after each system defrost cycle. The heat pump control
monitors ambient temperature, outdoor coil temperature,
and total run-time to determine when a defrost cycle is
required. The coil temperature sensor is designed with a
spring clip to allow mounting to the outside coil tubing. The
location of the coil sensor is important for proper defrost
operation.
NOTE – The heat pump control accurately measures the
performance of the system as frost accumulates on the
outdoor coil. This typically will translate into longer running
time between defrost cycles as more frost accumulates
on the outdoor coil before the heat pump control initiates
defrost cycles.
OPERATING MANIFOLD GAUGE SET AND SERVICE
VALVES
The liquid and vapor line service valves are used for re-
moving refrigerant, flushing, leak testing, evacuating,
checking charge and charging.
Each valve is equipped with a service port which has a
factory-installed valve stem. Figures 14 and 15 provide
information on how to access and operate both angle- and
ball-type service valves.
When servicing or repairing heating, ventilating and air
conditioning components, ensure the fasteners are appro-
priately tightened. Table 1 lists torque values for fasteners.
Page 18
Torque Requirements