Install Instructions

Installation Manual - B-VMH09,12,18CU-1
13
3.5 Additional refrigerant charge
CAUTION
Refrigerant may only be charged after performing the leak
test and the vacuum pumping.
Check the type of refrigerant to be used on the machine
nameplate. Charging with an unsuitable refrigerant may
cause explosions and accidents, so always ensure that the
appropriate refrigerant is charged.
Refrigerant containers shall be opened slowly.
The outdoor unit is factory charged with refrigerant. Calculate the
added refrigerant according to the diameter and the length of the
liquid pipe of the outdoor unit/indoor unit connection.
3.6 Refrigerant piping work
1) Caution on the pipe handling
Protect the open end of the pipe against dust and moisture.
All pipe bends should be as gentle as possible. Use a pipe
bender for bending.
Be sure to add the proper amount of additional refrigerant.
Failure to do so may result in reduced performance.
Pipe length Up to 15m/49.2ft More than 15m/49.2ft
Not less than 15minNot less than 10 minRun time
*2. If the compound pressure gauge pointer swings back,
refrigerant may have water content or a loose pipe joint may
exist. Check all pipe joints and relighted nuts as needed, then
repeat steps 2) through 4).
Be sure to
place a cap.
If no flare cap is
available, cover the
flare mouth with
tape to keep dirt or
water out.
Wall
Rain
Pipe length and refrigerant amount:
Connective
pipe length
Less
than 7.5m
More
than 7.5m
Air purging
method
Use vacuum
pump.
Use vacuum
pump.
Additional amount of refrigerant to be charged
Liquid side: 1/4in/6.35mm
R410A: (Pipe length-7.5(25))x15g/m(0.16oz/ft)
Liquid side: 3/8in/9.52mm
R410A: (Pipe length-7.5(25))x30g/m(0.32oz/ft)
Do not mix any substance other than the specified refrigerant
into the refrigeration cycle.
When refrigerant gas leaks occur, ventilate the room as soon as
possible.
The specified refrigerant should always be recovered and never
be released directly into the environment.
Use a vacuum pump for the specified refrigerant. Using the
same vacuum pump for different refrigerants may damage the
vacuum pump or the unit.
If using additional refrigerant, perform air purging from the
refrigerant pipes and indoor unit using a vacuum pump, then
charge additional refrigerant.
Use a hexagonal wrench (0.2in/4mm) to operate the stop valve
rod.
All refrigerant pipe joints should be tightened with a torque
wrench at the specified tightening torque.
When piping work is completed, it is necessary to purge the
air and check for gas leakage.
3.4 Purging air and checking gas leakage
1) Connect projection side of charging hose (which comes from
gauge manifold) to gas stop valve's service port.
2) Fully open gauge manifold's low-pressure valve (Lo) and
completely close its high-pressure valve (Hi)
(High-pressure valve subsequently requires no operation.)
3) Do vacuum pumping and make sure that the compound
pressure gauge reads -0.1MPa (-76cmHg).*1
4) Close gauge manifold's low-pressure valve (Lo) and stop
vacuum pump.
(Keep this state for a few minutes to make sure that the
compound pressure gauge pointer does not swing back.)*2
5) Remove caps from liquid stop valve and gas stop valve.
6) Turn the liquid stop valve's rod 90 degrees counterclockwise
with a hexagonal wrench to open valve.
Close it after 5 seconds, and check for gas leakage.
Using soapy water, check for gas leakage from indoor unit's
flare and outdoor unit's flare and valve rods.
After the check is complete, wipe all soapy water off.
7) Disconnect charging hose from gas stop valve's service port
then fully open liquid and gas stop valves.
(Do not attempt to turn valve rod beyond its stop.)
8) Tighten valve caps and service port caps for the liquid and gas
stop valves with a torque wrench at the specified torques.
*1. Pipe length vs. Vacuum pump run time
WARNING