Installation Guide

Page 29 mrcool.com
Air Evacuation
Note on Adding Refrigerant
Some systems require additional charging depending on pipe lengths. The standard pipe length varies according to local
regulations. For example, in North America, the standard pipe length is 25ft (7.5m). In other areas, the standard pipe
length is 16ft (5m). The additional refrigerant to be charged can be calculated using the following formula:
Flare nut
Cap
Valve body
Valve stem
Fig. 7.2
11. Remove the charge hose from the service port.
12. Using hexagon wrench, fully open both the high
pressure and low pressure valves.
13. Tighten valve caps on all three valves (service port,
high pressure, low pressure) by hand. You may tighten it
further using a torque wrench if needed.
OPEN VALVE STEMS GENTLY
When opening valve stems, turn the hexago-
nal wrench until it hits against the stopper. Do
not try to force the valve to open further.
ADDITIONAL REFRIGERANT PER PIPE LENGTH
Connective
Pipe Length (m)
Air Purging
Method
Additional Refrigerant
≤ Standard pipe length
N/A N/A
> Standard pipe length Vacuum Pump
Inverter R410A:
(Pipe length – standard length) x 15g/m
(Pipe length – standard length) x 0.16oZ/ft
Fixed-frequency R410A:
(Pipe length – standard length) x 20g/m
(Pipe length – standard length) x 0.21oZ/ft
Inverter R410A:
(Pipe length – standard length) x 30g/m
(Pipe length – standard length) x 0.32oZ/ft
Fixed-frequency R410A:
(Pipe length – standard length) x 40g/m
(Pipe length – standard length) x 0.42oZ/ft
CAUTION
DO NOT mix refrigerant types.
Vacuum Pump
Liquid Side: Ø 0.25” (ø 6.35)
Liquid Side: Ø 0.375” (ø 9.52)
3. Open the Low Pressure side of the manifold gauge.
Keep the High Pressure side closed.
4. Turn on the vacuum pump to evacuate the system.
5. Run the vacuum for at least 15 minutes, or until the
Compound Meter reads -76cmHG (-105 Pa).
6. Close the Low Pressure side of the manifold gauge,
and turn off the vacuum pump.
7. Wait for 5 minutes, then check that there has been
no change in system pressure.
8. If there is a change in system pressure, refer to Gas
Leak Check section for information on how to check for
leaks. If there is no change in system pressure, unscrew
the cap from the packed valve (high pressure valve).
9. Insert hexagon wrench into the packed valve (high-
pressure valve) and open the valve by turning the wrench
in a 1/4 counter clockwise turn. Listen for gas to exit the
system, then close the valve after 5 seconds.
10. Watch the Pressure Gauge for one minute to make
sure that there is no change in pressure. The Pressure
Gauge should read slightly higher than atmospheric
pressure.