2. Guideline for each installation process
13
_ Heat pump
50Hz/R410A
Part 3 Design and installation
2.2.5 Refrigerant pipe flushing
Flushing is a method of cleaning extraneous matter out of pipes using pressurized gas.
①
Set pressure regulator on nitrogen cylinder.
②
Connect the charge hose from pressure regulator to
service port on the liquid pipe side of the outdoor unit
before its connection to B/D unit or indoor unit.
③
Open the main valve on the nitrogen cylinder and set
the pressure regulator to 0.5MPa.
④
Ensure that nitrogen is flowing through the pipe properly.
⑤
For flushing block the end of the pipe with wood insula-
tion block.
⑥
When the pressure becomes great remove the block
quickly.
⑦
Do step 6 & 7 repeatedly till cleanness is ensured.
⑧
Connect the charge hose from pressure regulator to
service port on the gas pipe side of outdoor unit before
its connection to B/D unit or indoor unit.
⑨
Flow the steps 3, 4, 5, 6, 7.
⑩
In case of BD unit system, before connecting to indoor
units, each pipe should be flushed individually.
⑪
Flow the steps 3, 4, 5, 6, 7.
Refrigerant pipe flushing of 3 major effects
1. Removal of oxidation bubbles formed inside copper pipes when “nitrogen replacement is insufficient”
during soldering work
2. Removal of extraneous material and moisture from pipes when covering has been insufficient
3. Checks connections in pipes linking outdoor and indoor units (Both liquid and gas pipes)
NOTE
After welding the pipe, nitrogen flushing is strongly
recommended.
CAUTION
Gas pressure of 0.5 MPa
Taping
Nitrogen
Lo
Hi
Wood
Insulation
Primary
side
Pressure regulator
Nitrogen
Lo
Hi
Secondary
side 0.5 MPa
Nitrogen
Lo
Hi
