35
PMML0129A rev.4 - 02/2010
ENGLISH
■
Insulate Pipes
Insulate the refrigerant pipes as shown below
After connecting the refrigerant piping, seal the refrigerant pipes
by using the field-supplied insulation material. Insulate the unions
and flare-nuts at the piping connections completely. Insulate the
liquid piping and gas piping completely to avoid decreasing of
performance and dewing on the surface of the pipe.
Caution on Refrigerant Leakage
Specifiers/installers have responsibility to follow local codes and
regulation which specify safety requirements against refrigerant
leakage.
Maximum Permissible Concentration of HCFC/HFC Gas
The refrigerant R410A, charged in the HRNM system, is an
incombustible and non-toxic gas. However, if leakage occurs
and gas fills a room, it may cause suffocation.
The maximum permissible concentration of HCFC/HFC gas,
R410A in air is 0.44 kg/m³, according to EN378-1
Therefore, some effective measure must be taken to lower the
R410A concentration in air below 0.44 kg/m³, in case of leakage.
Calculation of Refrigerant Concentration
1. Calculate the total quantity of refrigerant R (kg) charged in
the system connecting all the indoor units of rooms to be air-
conditioned.
2. Calculate the room Volume V (m³) of each room.
3. Calculate the refrigerant concentration C (kg/m³) of the room
according to the following equation:
R
___ < C
V
R: Total Quantity of Charged Refrigerant (kg)
V: Room Volume (m³)
C: Refrigerant Concentration 0.44 kg/m³ for R410A
Countermesure for Refrigerant Leakage According to KHK
Standard
1. Provide a shutterless opening which allow fresh air to
circulate into the room.
2. Provide a doorless opening of 0.15% or more size to the floor area.
3. Pay a special attention to the place, such as a basement, etc.,
where refrigerant can stay, since refrigerant is heavier than air.
12.1.3. PIPING CONNECTION
- Pipes can be connected from 4 directions. Make holes in the
piping cover or cabinet for taking out pipes. Take the piping
cover away from the unit, and make holes by cutting along
the guideline at the rear of the cover or punching with a driver.
Remove the burr with a cutter.
(a) Front and Right Side Piping Work Select the correct knock-
out size depending on whether it is for power wiring or
transition wiring.
B
A
It is available to correct the liquid or gas piping, power wiring
less than 14mm
2
and transition wiring from “A” part.
NOTES:
When using conduit, check to the tube size before
removing “B” part.
Front side
Piping cover
Front side
Piping work
(knock-out hole)
Bottom side piping work
Piping work
(Piping cover)
Right side piping work
(knock-out hole)
Rear side piping work
(knock-out hole)
Rear side piping cover
Hole down the
cover slowly
Front side piping cover
Rear side piping cover
Rear cover
Front Side Piping Hole
Right Side Piping Hole
Stop Valve
Insulation
(Field Supply)
Refrigerant Piping
(Field Supply)
PIPING AND
REFRIGERANT CHARGE
