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When the Operation Mode jumper is installed in the "Com-
fort Mode" the suction pressure setpoint is 125 psig.
Unit Operation
EL18XCV Unit Operation with a S30 Communicating
Thermostat
When the EL18XCV 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.
EL18XCV Unit Operation with a Conventional 24VAC
Non-Communicating 2-Stage Thermostat
When the EL18XCV unit is installed with a conventional
24VAC non-communicating 2-stage thermostat, a Y1 first
stage cooling demand will initiate 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 cooling demand will initi-
ate second stage blower operation. Increased air volume
will increase the load on the indoor coil and increase the
suction pressure. The EL18XCV compressor capacity will
continue to be controlled based upon the suction pres-
sure. The unit capacity will be controlled in the variable
capacity mode throughout the range of capacity from min-
imum capacity to maximum capacity. If the Y2 demand
remains after 20 minutes, the EL18XCV control will begin
to ramp up the compressor capacity until maximum ca-
pacity is achieved. The EL18XCV unit will cycle off once
the thermostat demand is satisfied.
EL18XCV Unit Operation with a Conventional 24VAC
Non-Communicating Single-Stage Thermostat
When the EL18XCV unit is installed with a conventional
24VAC non-communicating single-stage thermostat, a Y1
first stage cooling demand will initiate cooling operation
and cooling indoor blower operation. In single stage ther-
mostat applications, a jumper must be installed between
Y1 and Y2 on the EL18XCV outdoor control. The com-
pressor will be controlled in the variable capacity mode
by varying the compressor capacity to obtain the target
suction pressure set point. If the cooling demand remains
after 20 minutes, the EL18XCV control will begin to ramp
up the compressor capacity until maximum capacity is
achieved. The EL18XCV unit will cycle off once the ther-
mostat 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.
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 2 lists torque values for fasteners.
TABLE 1
Parts
Service valve cap
Sheet-metal screws
Machine screws #10
Compressor bolts
Gauge port seal cap
To prevent stripping of the various caps used, the
appropriately sized wrench should be used and fitted
snugly over the cap before tightening.
Using Manifold Gauge Set
When checking the system charge, only use a manifold
gauge set that features low loss anti-blow back fittings.
Manifold gauge set used with HFC-410A refrigerant sys-
tems must be capable of handling the higher system oper-
ating pressures. The gauges should be rated for use with
pressures of 0 - 800 psig on the high side and a low side
of 30" vacuum to 250 psig with dampened speed to 500
psi. Gauge hoses must be rated for use at up to 800 psig
of pressure with a 4000 psig burst rating.
Page 18
Torque Requirements
– TORQUE REQUIREMENTS
Recommended Torque
8 ft.-lb.
16 in.-lb.
28 in.-lb.
90 in.-lb.
8 ft.-lb.
IMPORTANT
11 NM
2 NM
3 NM
10 NM
11 NM
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