Refrigerant Piping - Daikin LREQ-BY1 Installation Manual

6.

REFRIGERANT PIPING

To Piping Work Contractors
• Never open the shutoff valve until the steps specified in
WIRING" on page 11 and "8-3 Checking of device and installation
conditions" on page 16 of piping.
• Do not use flux at the time of brazing and connecting refrigerant
pipes. Use phosphorous copper brazing filler metal (BCuP-2),
which does not require flux. Chlorine-based flux causes piping
corrosion. Furthermore, if fluoride is contained, the flux will have
adverse influences on the refrigerant piping line, such as the
deterioration of refrigerating machine oil.
CAUTION
• All field piping must be installed by a licensed refrigeration
technician and must comply with relevant local and national
regulations.
[Precautions for reuse of existing refrigerant piping/heat
exchangers]
Keep the following points in mind for the reuse of existing
refrigerant piping / heat exchangers.
A malfunction may result if there is deficiency.
• Do not use the existing piping in the following cases. Perform new
piping instead.
• The piping is different in size.
• The strength of the piping is insufficient.
• The compressor of the condensing unit previously used caused a
malfunction.
An adverse influence of residual substances, such as the oxidation
of refrigerant oil and the generation of scale, is considered.
• If the indoor unit or outdoor unit is disconnected from the piping for
a long time.
The intrusion of water and dust into the piping is considered.
• The copper pipe is corroded.
• The refrigerant of the condensing unit previously used was other
than R410A (e.g., R404A / R507 or R407C).
The contamination of the refrigerant with heterogeneity is
considered.
• If there are welded connections midway on the local piping, make
gas leakage checks on the welded connections.
• Be sure to insulate the connection piping.
The liquid and gas pipe temperatures are as follows:
Liquid pipe arrival minimum temperature: 0°C
Gas pipe arrival minimum temperature: –45°C
In the case of thickness insufficiency, add additional insulation
material or renew the existing insulation material.
• Renew the insulation material if the insulation material is degraded.
Keep the following points in mind for the reuse of existing heat
exchangers
• Units with insufficient design pressure (since this product is an
R410A unit) require a lower-stage design pressure of 2.5 MPa
[25 bars].
• Units for which the path to the heat exchanger has been routed so
that the flow of refrigerant is from bottom to top
• Units with copper tubing or fan corrosion
• Units that may be contaminated with foreign matter such as
rubbish or other dirt
LREQ5~20B7Y1
Air cooled refrigeration condensing unit
4PW74302-1D – 2016.11
"7. FIELD
Installation manual
6