Refrigerant Charging; Electronic Function; Abbreviation; Electric Control Working Environment - Lennox MCA Series Service Manual

13.7.2. Refrigerant Charging

• Connect the charge hose to the charging cylinder, open
the two-way valve and the three-way valve.
• Connect the charge hose which you disconnected from
the vacuum pump to the valve at the bottom of the
cylinder. If the refrigerant is R-410A, make the cylinder
bottom up to ensure liquid charge.
• Purge the air from the charge hose
• Open the valve at the bottom of the cylinder and press
the check valve on the charge set to purge the air (be
careful of the liquid refrigerant).
• Put the charging cylinder onto the electronic scale and
record the weight.
• Open the valves (Low side) on the charge set and
charge the system with liquid refrigerant. If the
system cannot be charge with the specified amount
of refrigerant, or can be charged with a little at a time
(approximately 150g each time) , operating the air
conditioner in the cooling cycle; however, one time is
not sufficient, wait approximately 1 minute and then
repeat the procedure.
• When the electronic scale displays the proper weight,
disconnect the charge hose from the 3- way valve's
service port immediately
• If the system has been charged with liquid refrigerant
while operating the air conditioner, turn off the air
conditioner before disconnecting the hose.
• Mounted the valve stem caps and the service port.
Use torque wrench to tighten the service port cap to a
torque of 18N·m (13.27 ft·lbs).
• Always leak check after servicing the refrigerant
system.
There are one low-pressure centralized valve and one high-
pressure centralized valve, it will be more time saving when
vacuum and recycle refrigerant. But refer to the previous
instruction when vacuum and recycle refrigerant.

14. Electronic Function

14.1. Abbreviation

• T1: Indoor ambient temperature
• T2: Middle indoor heat exchanger coil temperature
• T3: Outdoor heat exchanger pipe temperature
• T4: Outdoor ambient temperature
• T5: Compressor discharge temperature
14.2. Electric Control Working
Environment.
• Input voltage: 230V.
• Input power frequency: 60Hz.
• Indoor fan standard working amp.: <1A
• Outdoor fan standard working amp.: <1.5A.
• Four-way valve standard amp.: <1A

15. Adding Refrigerant - Single-Zone Systems

The outdoor unit is factory-charged with refrigerant. Calculate
the additional refrigerant required according to the diameter
and the length of the liquid pipe between the outdoor unit
and indoor unit connections.
Be sure to add the proper amount of additional refrigerant.
Failure to do so may result in reduced performance.
See "Table 4. Line Set Guide" on page 23 for how much
refrigerant needs to be added based on pipe length.
NOTE: Interconnecting pipe work between outdoor and
indoor units must be 10 ft. or longer.
NOTE: Do not remove refrigerant for line lengths less
than 25 ft. R-410A is a blended refrigerant. If you
must remove charge, it is necessary to remove
the entire charge and weigh in the new charge.

16. Single-Zone Outdoor Unit LED Locations

Single-zone outdoor units display flash codes on the main
board. The main board is accessed through the top of the
unit. Indoor units will display more detailed error codes.
These outdoor units do not have a SW1 spot check push
button switch. Diagnostic is performed through a series of
blue, red and green LEDs.
NOTE: The control on all single-zone outdoor units is
mounted with all LEDs down and cannot be seen
unless the control is removed.
Figure 25. Typical Location of Outdoor Unit LEDs
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