REMOTE CONDENSING UNIT

28

26

24

32

30

22

20

18

36

34

16

14

12

10

8

6

4

50

System Startup

Final Charge Adjustment

(Non-Matching Systems—Cooling Operation)

I

NDOOR

C

OIL WITH

E

XPANSION

V

ALVE

:

At stabilized cooling conditions and with an outdoor temperature of 60°F or higher, the system should have from

9°F to 15°F subcooling. For a proper subcooling reading, measure the refrigerant pressure and temperature at the outdoor unit’s liquid line service valve. If you have less than

9°F subcooling, add charge. If you have more than 15°F subcooling, remove charge.

I

NDOOR

C

OIL WITH

O

RIFICE OR

C

AP

T

UBE

:

For a proper superheat reading, measure the refrigerant pressure and temperature at the outdoor unit vapor line service valve. The superheat should be within 3°F of that shown on the Desired Superheat vs Outdoor Temperature

chart (following page). If the superheat is more than 3°F

higher than shown on the chart, add charge. If the superheat is more than 3°F lower than shown on the chart, remove charge.

EXAMPLE: The low side pressure is 84 psi. The low side temperature is 80°F. The outdoor temperature is 95°F.

The indoor temperature is 85°F. By referring to a pressure temperature chart, you will see that 84 psi equals a saturated temperature of 50°F. The superheat is 80 - 50 = 30°F.

The chart shows a superheat of 20°F is ideal for these conditions. Since our superheat is 30 - 20 = 10°F higher than ideal, charge must be added.

If the system is performing properly, reinstall the service port caps and the valve bonnets. With the valve opened, the valve bonnet is the primary seal against refrigerant leaks. Apply two drops of clean oil to the cap threads, allowing the oil to run down to the inner cap seal surface.

Close caps finger-tight. Then tighten cap an additional two to three hex flats. NOTE: Subsequent opening and replace of the cap will require only 1/2 to 1 hex flat. See the table below for the torque required for an effective seal on the valve bonnet (1/6 turn past finger tight).

Tubing Size

3/8

1/2, 5/8, 3/4

7/8, 1 1/8

Torque (Foot-Pounds)

10

14

16

After closing the valve bonnet, perform a final refrigerant leak test on the valves and sweat connections. Return the room thermostat to the desired settings.

DESIRED SUPERHEAT vs OUTDOOR TEMPERATURE

60

70

° F

In do or

90° F

Ind

85°

F In do or oor

75

° F

In do or

80°

F I ndo or

110 120 70 80 90

OUTDOOR TEMPERATURE

12

100