Unit Start−Up; Delivered Void Of Charge - Lennox Merit 13HPX Series Installation Instructions Manual

Unit Start−Up
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.
UNIT START−UP
1. Rotate fan to check for binding.
2. Inspect all factory− and field−installed wiring for loose
connections.
3. Verify that the manifold gauge set is connected as
illustrated in figure 19. Use a temperature sensor
positioned near the liquid line service port as illustrated
in figure 19 which will be required later when using the
subcooling method for optimizing the system
refrigerant charge.
4. Replace the stem caps and tighten to the value listed
in table 1.
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. Open both the liquid and vapor line service valves to
release the refrigerant charge contained in outdoor
unit into the system.
7. Use figure 18 to determine next step in system
preparation.
OPEN BOTH VAPOR AND LIQUID SERVICE
REFRIGERANT FROM OUTDOOR UNIT TO
NO
GO TO SERVICE AND WEIGH
IN REFRIGERANT CHARGE
FOR OUTDOOR UNITS

DELIVERED VOID OF CHARGE

ON PAGE 23.
Figure 18. Outdoor Unit Factory Charge
Downloaded from ManualsNet.com
IMPORTANT
VALVE STEMS TO RELEASE
SYSTEM.
REFRIGERANT
YES
PRESENT
GO TO OPTIMIZING SYSTEM
REFRIGERANT CHARGE ON
PAGE 25.
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Service and Weigh In Refrigerant for
Outdoor Units Delivered Void of Charge
The following procedures are only required if it has been
determine that the new outdoor unit is void of charge. Skip
to the next section if refrigerant charge is present.
LEAK CHECK, REPAIR AND EVACUATE
If the outdoor unit is void of refrigerant, clean the system
using the procedure described below.
1. Leak check system using procedures provided on
page 16. Repair any leaks discovered during leak test.
2. Evacuate the system using procedure provided in
figure 13.
3. Use nitrogen to break the vacuum and install a new
filter drier in the system.
4. Evacuate the system again using procedure in figure
13.
CONNECT MANIFOLD GAUGE SET AND WEIGH IN
CHARGE
After the evacuation procedure, reconnect the manifold
gauge set as illustrated in figure 19.
NOTE − Temperature sensor illustrated in figure 19 is not
required for initial system weigh in charging.
1. Close manifold gauge set valves and connect the
gauge set as exampled in figure 19.
2. Check that fan rotates freely.
3. Inspect all factory− and field−installed wiring for loose
connections.
4. Open the high side manifold gauge valve and weigh in
liquid refrigerant. Use figure 20 to calculate the correct
weigh−in charge.
5. Close manifold gauge valves.
6. Monitor the system to determine the amount of
moisture remaining in the oil. It may be necessary to
replace the bi−flow filter drier several times to achieve
the required dryness level. If system dryness is not
verified, the compressor will fail in the future.
7. Continue to Optimizing System Refrigerant Charge
on page 25 to optimize the system charge using
subcooling method.
Page 23
13HPX SERIES