INST
ALLA
TION
INSTUCTIONS
INST
ALLA
TION
INSTUCTIONS
P27 OF 34
P28 OF 34
VACUUM AND LEAKAGE CHECK
Evacuate the pipes between indoor and outdoor units, using vacuum pump and manifold/gauge set, to a
minimum of 500 microns (service valves remain front seated). Hold for 30 minutes to check if the vacuum level is
maintained. Using dry nitrogen or other leakage detection tool for leak checking. Be certain there is no pressure
in the system when repairing a leak.
Vacuum and Check Leakage before Releasing Refrigerant from Outdoor Unit to Indoor Unit
VACUUM REFRIGERANT PIPES
Service valve
Hexagon
Allen wrench
VACUUM
Humid air left inside the refrigerant circuit can
cause compressor malfunction and failure.
After having connected the indoor and outdoor
units, the air and humidity from the refrigerant
circuit using a vacuum pump.
1) Unscrew and remove the caps from the
2-way and 3-way valves.
2) Unscrew and remove the cap from the
service valve.
3) Connect the vacuum pump hose to the
service valve.
4) Operate the vacuum pump for 10-15
minutes until an absolute vacuum of 500
micron has been reached.
5) With the vacuum pump still in operation,
close the low-pressure knob on the vacuum
pump coupling.
Stop the vacuum pump.
6) Open the 2-way valve by 1/4 turn and then
close it after 10 seconds. Check all the
joints for leaks using liquid soap or an
electronic leak device.
7) Turn the body of the 2-way and 3-way
valves. Disconnect the vacuum pump hose.
8) Replace and tighten all the caps on the
valves.
Vacuum pump
INDOOR UNIT
Refrigerant fluid direction of flow
3-way valve
Service
inlet
(2) Turn
(8) Secure
Valve cap
(7) Turn to open fully
(2) Turn
(8) Secure
Connect to the
indoor unit
(8) Secure
(2) Turn
2-way valve
(6) Open by 1/4 turn
(7) Turn to open
fully
Valve cap
3-way valve
Blank cap
Refrigerant pipe
Outdoor unit
Cap
Service hose
with valve core
Compound pressure gauge
Gauge manifold
Pressure gauge
High pressure
side valve
(closed)
Service hose
Vacuum pump
Service hose
Low pressure
side valve
-100 kPa
-76cm.Hg
-1 bar
(For a description of how to use the
gauge manifold, refer to the gauge
manifold operation manual.)
YMGI, Engineered Comfort Products for A Sustainable and Efficient Green World !
YMGI, Engineered Comfort Products for A Sustainable and Efficient Green World !
RELEASE REFRIGERANT FROM OUTDOOR TO THE INDOOR UNIT
Unit is pre-charged with refrigerant good for 25' of
connection tubes. If vacuum is held for about 30
minutes and no leak is found, first back-seat the
liquid (smaller) service valve by Allen Wrench (hex
head) slowly to release pre-charged refrigerant from
the condensing unit into the connection pipes and
indoor unit. If no abnormal things are found, fully
open liquid (smaller) and gas (bigger) service
valves. Always replace and tighten the caps onto
service valves.
Releasing Refrigerant from Outdoor Unit to Connected
Pipes and Indoor Unit
SYSTEM INSPECTION AND TRIAL RUNNING
CHECK SYSTEM THOROUGHLY
Check system thoroughly to make sure the unit is ready for trial running: check wires and pipes and air intake and discharge
and power and thermostat and others necessary components.
liquid
connecting
pipe
liquid closing valve
gas conne-
cting pipe
screw cap
gas
charging
hole
screw cap
allen wrench
ADJUST REFRIGERANT-GUIDELINE
Right amount of refrigerant is very important. It is one of the basics to ensure unit a safe operation over time.
Normally single zone outdoor unit is pre-charged with refrigerant for 25ft inter-connecting copper (liquid) line. Multiple zone outdoor unit is
pre-charged for various length of copper (liquid) lines of allowed quantity of indoor units, following specs. or engineering submittal.
For single zone unit or multiple zone multiple compressor unit, normally the outdoor unit is pre-charged for 25ft line sets. If the copper line is
longer or shorter than 25ft, need to add or deduct refrigerant, following general rule of thumb for rough adjustment:
1/4" liquid line unit: 0.3 Oz/ft; 3/8" liquid line unit: 0.4 OZ/ft; 1/2" liquid line unit: 1.2 OZ/ft.
For multiple zone one compressor unit, if the copper line is longer or shorter than the length at which pre-charged refrigerant is good for, as
listed in the engineering submittal or related labels or tables, need to add or deduct refrigerant, following 0.23 OZ/ft rule of thumb for rough
adjustment.
In all situations, the minimum copper line (liquid or gas) length for each indoor unit is 15ft.
For a better adjustment, may combine above guideline with the indoor or outdoor (ambient) temperature-refrigerant pressure chart, or
generally 8-12F super-heat method.
Model
Liquid valve
In.
1/4
1/4
1/4
1/4
1/4
1/4
1/4
1/4
1/4
1/4
1/4
1/4
1/4
Gas valve
3/8
3/8
3/8
3/8
3/8
3/8
3/8
3/8
3/8
3/8
3/8
3/8
3/8
Max. pipe length (add up length of all liquid lines only), if not upper sizing pipes
120
200
230
260
Max. installed indoor and
outdoor unit elevation difference
Outdoor unit is installed below the indoor unit
Ft.
15
25
30
30
Outdoor unit is installed above indoor unit
Ft.
25
25
30
30
Max. pipe length, if not adjusting factory pre-charged refrigerant
Ft.
100 (add up length of all liquid lines only) 130 (add up length of all liquid lines only)
Minimum pipe length (for each indoor unit)
/
15ft
Refrigerant charge adjustment, if actual length is different from the number in the line above
+- Oz/Ft
0.23
In.
Ft.
* Adjust refrigerant charge, following instructions, if the actual installation elevation difference is different from 7'
and length is different from the listed numbers above.
* Any indoor unit is 30' or more apart from the outdoor unit, better to adjust refrigerant. If it is 50' or more apart,
better to upper size the copper lines and adjust refrigerant.
* Any run can not be more than 100' apart from the outdoor unit; otherwise, that indoor unit 's capacity may be
decreased too much.
Valve sizes at outdoor unit
60 (add up length of all liquid lines only) 100 (add up length of all liquid lines only)
WMMS-21CH-V2B(59)(2)
WMMS-30CH-V2B(59)(2)
WMMS-24CH-V2B(59)(2)
WMMS-36CH-V2B(59)(2)
WMMS-42CH-V2B(59)(2) WMMS-48CH-V2B(59)(2)
WMMS-60CH-V2B(59)(2)
1/4
1/4
1/4
1/4
3/8
3/8
1/2
1/2
300
30
30
130 (add up length of all liquid lines only)
1/4
5/8
