Maximum Allowable Height Difference; Precautions On Refrigerant Piping; Caution For Brazing - Daikin KHRQ23M29H Installationsanleitung

Maximum allowable height difference

Difference in height between outdoor and indoor units
H1≤40 m
Difference in height between lowest and heighest
indoor unit H2≤15 m
NOTICE
When the equivalent pipe length between outdoor and
indoor units is 90 m or more, the size of the main liquid
pipe must be increased. Never increase suction gas pipe
and HP/LP gas pipe sizes.
Depending on the length of the piping, the capacity may
drop, but even in such a case it is possible to increase the
size of the main liquid pipe.
HP
10
12~16
Make sure to perform the piping installation within the
range of the maximum allowable pipe length, allowable
level difference and allowable length after branching as
indicated above.
1 2 3
1 Outdoor unit
2 Main pipes
3 Increase only liquid pipe size
4 First refrigerant branch kit
5 Branch selector box
6 Indoor unit
7 HXHD125 indoor unit
10. P
RECAUTIONS ON REFRIGERANT PIPING
Do not allow anything other than the designated refrigerant to
get mixed into the freezing cycle, such as air, etc. If any
refrigerant gas leaks while working on the unit, ventilate the
room thoroughly right away.
Use R410A only when adding refrigerant
Installation tools:
Make sure to use installation tools (gauge manifold charge hose,
etc.) that are exclusively used for R410A installations to
withstand the pressure and to prevent foreign materials (e.g.
mineral oils and moisture) from mixing into the system.
Vacuum pump:
Use a 2-stage vacuum pump with a non-return valve.
Make sure the pump oil does not flow oppositely into the system
while the pump is not working.
Use a vacuum pump which can evacuate to –100.7 kPa (5 Torr,
–755 mm Hg).
Installation manual
13
H1
H2
Liquid Ø (mm)
→
9.5 12.7
→
12.7 15.9
4 5 6 7
Protection against contamination when installing pipes
- Take measures to prevent foreign materials like moisture and
contamination from mixing into the system.
Installation period
More than a month
Less than a month
Regardless of the period
- Block all gaps in the holes for passing out piping and wiring
using sealing material (field supply). (The capacity of the unit
will drop and small animals may enter the machine.)
Example: passing piping out through the front
1
- Use clean pipes only
- Hold the pipe end downwards when removing burrs
- Cover the pipe end when inserting it through a wall so that no
dust or dirt enters the pipe.
NOTICE
After all the piping has been connected, make sure there is
no gas leak. Use nitrogen to perform a gas leak check.

10.1. Caution for brazing

Make sure to blow through with nitrogen when brazing.
Blowing through with nitrogen prevents the creation of large
quantities of oxidized film on the inside of the piping. An oxidized
film adversely affects valves and compressors in the
refrigerating system and prevents proper operation.
The nitrogen pressure should be set to 0.02 MPa (i.e., just
enough so it can be felt on the skin) with a pressure-reducing
valve.
1 2
6
1 Refrigerant piping
2 Part to be brazed
3 Taping
4 Hands valve
5 Pressure-reducing valve
6 Nitrogen
Do not use anti-oxidants when brazing the pipe joints.
Residue can clog pipes and break equipment.
Do not use flux when brazing copper-to-copper refrigerant
piping. Use phosphor copper brazing filler alloy (BCuP) which
does not require flux.
Flux has an extremely harmful influence on refrigerant piping
systems. For instance, if chlorine based flux is used, it will cause
pipe corrosion or, in particular, if the flux contains fluorine, it will
deteriorate the refrigerant oil.
Protection method
Pinch the pipe
Pinch or tape the pipe
1 Plug the areas marked with
" ".
(When the piping is routed
from the front panel.)
3 4 5
6
REYAQ10~16P7Y1B
VRVIII system outdoor unit
4PW62582-1A – 08.2011