VRF Air-Conditioner IOM
5
Excessive tightening may damage horn mouth and
lead to refrigerant leakage.
5.2
Air tightness leakage detection
Conduct
air
tightness
leakage
detection
confirmation at the end of piping work.
Leakage detection method:
(a)
Fill dry compressed nitrogen into indoor unit and
piping system, and slowly boost the pressure to
4.3MPa;
(b)
After maintaining pressure for 10min, coat soapy
water or other foaming agent at the connection
position such as weld and thread joint, and
observe whether there is leakage;
(c)
If any leakage, tighten or repair weld leaking
position after pressure relief.
(d)
Fill into dry compressed nitrogen again and
slowly boost the pressure to 4.3MPa;
(e)
Start to record the reading of pressure gauge after
maintaining pressure for 6h, and then record the
reading of pressure gauge again after 24h;
(f)
If no pressure drop, then the air tightness is
qualified. If any pressure drop, find out the
leakage point and repair, and then repeat the
above d and e procedures until qualified.
Pressure reading is related to temperature
variation, so the temperature variation factor shall
be considered when judging whether there is
pressure drop. The relation of pressure correction
value and temperature variation is:
−
+
+
∗
=
∆
1
273
273
1
2
1
t
t
P
P
P
P
P
∆
−
=
2
correction
△
P--Pressure correction value (bar)
P
correction
---Corrected pressure value (bar)
P
1
---The first pressure reading (bar)
P
2
---The second pressure reading (bar)
t
1
---Temperature at the first pressure reading (
)
℃
t
2
---Temperature at the second pressure reading
(
)
℃
In air tightness test, do not connect indoor unit
and outdoor unit, otherwise, nitrogen may leak to
outdoor unit.
5.3
Thermal insulation
If no leakage after inspection, respectively wrap
liquid pipe, gas pipe and each connecting position
with thick-enough heat-resistant polyethylene, and
conduct good thermal insulation.
Field piping must be connected to the piping
connecting part all the time. If poor thermal
insulation for piping, there will be dew outside
and scald if any touch.
6.
Installation of Drainage Piping
6.1
Drainage piping installation
In delivery, the drainage outlet is PVC pipe; in
connecting water pipe, please use auxiliary
sealing material and sleeve.
Conduct thermal insulation for drainage pipe of
indoor unit, otherwise, condensation may be
caused. The connecting part of indoor unit must
also be subjected to thermal insulation treatment.
Before installation, please confirm whether the
connection condition of pump defrosting tray and
the surface thermal insulation are intact.
For drainage pipe connection, use hard PVC
binding agent and confirm there is no leakage.
The junction of drainage pipe and drainage outlet
of indoor unit must be free from bearing any force,
including water pipe gravity.
The downward inclination of drainage pipe shall
be above (1/100) and the middle shall be free
from bending.
The transverse pull-out of drainage pipe shall be
within 20m. If the drainage pipe is longer, please
arrange a support to prevent bending.
Drainage system joints must be sealed against
water leakage.
The height from drainage pipe end to ground or
drainage channel bottom shall be larger than
50mm, and the drainage pipe end shall not be put
into water. When directly discharging condensed
water into foul ditch, bend drainage pipe upward
to a U-shaped water seal in order to avoid odor
entering into room through drainage pipe.
For concentrated construction of drainage pipe of
multiple indoor units during suspended ceiling
installation (with pump), arrange U-shaped bend
at the branch water pipe connecting each indoor
unit to prevent water return from main drainage
pipe.
For seat installation, dismantle pump assembly,
and directly connect the drainage pipe of
accessories to drainage outlet of defrosting tray.
Caution
Caution
Thermal insulation material
Incline
downward
above 1/100
