Mitsubishi Electric ECOV-X37VA Manuel D'installation page 27

7-3. Installation of liquid pipe
7-3-1. Installing the solenoid valve <liquid>
Install the solenoid valve <liquid> right in front of the expansion valve (upstream side). Installing the solenoid valve near the
outdoor unit may cause capacity shortage to the pump down and the high pressure switch may cut the unit.
7-3-2. Installing the strainer <liquid>
Install the strainer at the solenoid valve <liquid> inlet. Check the strainer during test run and remove contaminants.
7-3-3. Installing the dryer
Be sure to attach a dryer to the unit outlet (liquid pipe).
When installing the dryer, do not leave the dryer open for more than 30 seconds. Install the dryer in the correct orientation.
Failure to install the dryer may cause damage to the compressor.
Procure a dryer locally.
Select the most suitable dryer that meets the following criteria.
• R744-compatible
• With a 100% molecular sieve solid core
• Design pressure of 8.0 MPa or higher
7-3-4. Installing the sight glass
Provide a sight glass to the unit outlet (liquid pipe).
Procure a sight glass locally.
Select a sight glass that meets the following criteria.
• R744-compatible
• Design pressure of 8.0 MPa or higher
• With a water-level indicator
7-3-5. Installing a pressure relief device
A pressure relief device must be installed on the liquid pipe.
Select a safety valve that has an activation threshold at or below 8.0 MPa.
7-3-6. When the ambient temperature around the pipe rises high
If the liquid pipe is heated by the effect of other heat source, flash gas is generated and a poor cooling problem occurs.
Route the liquid pipe where the temperature is low. Insulate the liquid pipe if it is installed in place where the temperature is
high.
7-3-7. When the evaporator is installed below the main suction pipe
When an evaporator is installed below the main suction
pipe, provide a small trap on the evaporator outlet to pre-
vent the effect from the liquid refrigerant to the tempera-
ture sensing valve of the expansion valve. Provide an
interlocking opposite trap above the main suction pipe to
prevent the liquid refrigerant/oil from flowing from the
main suction pipe to the riser pipe during stop operation.
A solenoid valve must be installed to each evaporator that
is installed above the main suction pipe as shown in the
figure on the right.
7-3-8. When there are multiple evaporators in the system
Equalize the pressure loss of each pipe circuit to equalize
the flowing amount of the refrigerant to each evaporator.
Branching point must be below the pipe. If the twinning
pipe is installed above the pipe, a sufficient amount of the
liquid refrigerant is not fed to the branched circuit, causing
a poor cooling problem.
Main suction pipe
Evapo-
rator
Expansion valve
Flow of liquid
refrigerant
Gravity
direction
27
Evapo-
S
rator
Downward
Evapo-
S
rator
S
Solenoid valve
Suction pipe
Main
pipe
Twinning pipe
Twinning
pipe
WT09614X03_GB