Piping Connection - Hitachi HRNM Série Manuel D'installation

Insulate Pipes
Insulate the refrigerant pipes as shown below
Stop Valve
Insulation
(Field Supply)
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 R: Total Quantity of Charged Refrigerant (kg)
V: Room Volume (m³)
C
V 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

-
Refrigerant Piping
(Field Supply)
Hole down the cover
(a) Front and Right Side Piping Work Select the correct
It is available to correct the liquid or gas piping, power
wiring less than 14mm
and transition wiring from "A" part.
PIPING AND REFRIGERANT CHARGE
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.
Front side
Piping cover
Bottom side piping work
Front side
Piping work
Piping work
(Piping Cover)
(knock-out hole)
slowly
Front side piping
cover
knock-out size depending on whether it is for power
wiring or transition wiring.
Right Side Piping Hole
Front Side Piping Hole
2
NOTES:
When using conduit, check to the tube size before
removing "B" part.
21
Rear side piping cover
Rear side piping work
(Knock-out hole)
Right side piping work
(Knock-out hole)
Rear Cover
Rear side piping cover