Bending Pipes; Pipe Connection; Installing Heat Insulation; Mounting Thermistors - Fujitsu Airstage Uty-Vdgu Installation Manual

5.3. Bending pipes

• The pipes are shaped by your hands or pipe bender. Be careful not to collapse them.
• Do not bend the pipes in an angle more than 90°.
• When pipes are repeatedly bend or stretched, the material will harden, making it difficult
to bend or stretch them anymore. Do not bend or stretch the pipes more than 3 times.
To prevent breaking of the pipe, avoid sharp bends.
If the pipe is bent repeatedly at the same place, it will break.

5.4. Pipe connection

If air or another type of refrigerant enters the refrigera-
tion cycle, the internal pressure in the refrigeration
cycle will become abnormally high and prevent the
unit from exerting its full performance.
Apply nitrogen gas while brazing the pipes.
Nitrogen gas pressure: 2.9 psi (0.02 MPa)
(= pressure felt sufficiently on the back of your hand)
If a pipe is brazed without applying nitrogen gas, it will create an oxidation film.
This can degrade performance or damage the parts in the unit (such as the compressor
or valves).
Do not use flux to braze pipes. If the flux is the chlorine type, it will cause the pipes to
corrode.
In addition, if the flux contains fluoride, it will affect the refrigerant piping system due to
deterioration of refrigerant oil.
For brazing material, use phosphor copper that does not require flux.
Connection Pipe (Liquid)
Connect the EEV unit pipe to the connection pipe. Braze the connectors.
When brazing the piping, take measures to prevent damage to the unit and surround-
ings due to heat.
(a) Connecting 1 EEV unit
Connection pipe
(locally purchased)
(b) Connecting 2 EEV units
If connecting 2 stacked EEV units, connect the special branch pipe (optional parts).
Relay pipes: Outside dimensions Ø 1/2 in
(Ø 12.7 mm) (locally purchased)
Relay pipes: Outside dimensions Ø 1/2 in
(Ø 12.7 mm) (locally purchased)
Branch pipes
(optional parts)
CAUTION
CAUTION
Pressure regulating valve
Cap
Nitrogen gas
Brazing area
Outer diameter of pipe [in (mm)]
1/2 (12.70)
Connection pipe
(locally purchased)
Branch pipes
(optional parts)

5.5. Installing heat insulation

After checking for gas leaks (refer to the installation manual of the outdoor unit), perform
this section. Failure to do so may cause water leaks.
Implement heat insulation as shown in the diagram below.
(1) Mount the rubber sheets (accessories).
(2) Mount the heat insulations (accessories). There should be no gaps between the
insulation and the product.
(3) Secure to a pipe using 2 cable ties.
(2) Heat insulations
(accessories)
(3) Cable ties
(Large, accessories)
• Perform the work in (1), (2) and (3) for the 2 pipes.
• For the heat insulation on the separation tube (Optional parts) used to connect 2 EEV
units, refer to the installation manual of the separation tube.
For construction other than mounting the EEV unit (e.g., mounting thermistors, electrical
wiring, and field settings, etc.), see the construction manual enclosed with the control
unit.

6. MOUNTING THERMISTORS

• To prevent water from accumulating on top of the thermistor, orient the thermistor wires
downwards when mounting the thermistor.
• Make good contact between thermistor and air handling unit. Put the top of the thermis-
tors on the air handling unit, this is the most sensitive point of the thermistor.
Mounting thermistors to general indoor units
General indoor unit
Refrigerant flow
during cooling
EEV
kit
A: Heat exchanger inlet pipe
Braze a thermistor holder pipe (Ø 1/4 in (Ø 6.35 mm), accessories) in front of the distribu-
tor branch.
Use a thermistor spring (accessories) to tightly seal and secure the thermistor (Ø 3/16 in
(Ø 4 mm), accessories) pipes.
(3)
(1) Thermistor holder pipe
(Ø 1/4 in (Ø 6.35 mm))
(3)
(2) Thermistor
(Ø 3/16 in (Ø 4 mm))
(2)
(3) Thermistor spring
(1)
* Attach this thermistor in a location where the evaporating temperature can be detected
during cooling operation.
B: Heat exchanger outlet pipe
Braze a thermistor holder pipe (Ø 3/8 in (Ø 9.53 mm), accessories) to the heat exchanger
outlet pipe.
Use a thermistor spring (accessories) to tightly seal and secure the thermistor (Ø 1/4 (Ø 6
mm), accessory) pipes.
CAUTION
(1) Butyl rubber sheets
(accessories)
No gap
Air inlet
C
A B
Heat
exchanger
D
Air outlet
(1) (2)
Heat
exchanger
Distributor
En-6