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Figure 9: Orifice Installation in TE2
Figure 10: Sensing Bulb Installation Position
Solenoid Valve
A suitably sized solenoid valve needs to be installed in the
liquid line just before the expansion valve on single
evaporator system and just before the 'T' piece in the main
liquid line on Twin systems. The liquid line solenoid valve is
not supplied in both Single and Twin system.
Figure 11: Position of Liquid Solenoid Valve
in Single System
Figure 12: Position of Liquid Solenoid Valve
in Twin System
Issue: 01.06.2023
Pressure Testing
Never use oxygen, dry air, or acetylene for
pressure testing of the system as these may
form an inflammable mixture.
Do not open the service valves on the
condensing unit until pressure testing
procedures have been carried out.
•
Both the indoor and outdoor units have been pressure
tested in the factory prior to dispatch. All units come
with a holding charge of oxygen free nitrogen
~2barg. Remove the holding charge and indication tag
prior to pipework installation using the service valve or
regulator with pressure gauges and hoses.
•
Once the pipework installation is complete, it should be
pressure tested for leak prior to evacuation.
•
A pressure leak test should be carried out using oxygen
free nitrogen (OFN). A calibrated nitrogen pressure
regulator must always be used. Before starting any
pressure testing, ensure the area surrounding the system
is safe, inform relevant personnel and fit warning signs
indicating high pressure testing. Also, use correct
Personal Protection Equipment (PPE) as required.
•
Always pressurize the system slowly, preferably in
stages up to the maximum required pressure. Never
exceed maximum test pressures shown in Table 8. Failure
to obey the limit will cause premature failure on the
pressure safety device.
Table 8: Maximum Working Pressure
High Side, barg (psig)
28 (405)
•
Listen for any possible leaks and check all joints with
bubble spray. If any leaks are discovered, release
pressure slowly from both suction and liquid line of
system until empty, repair leak and then repeat pressure
testing procedure. Never attempt to repair a leak on a
pressurized system.
•
A strength test should also be incorporated (to the
installed pipework only) according to applicable
standards.
•
Once testing has been completed satisfactorily, release
the pressure from the system gradually and safely to
external atmosphere.
Evacuation & Charging
Moisture prevents proper functioning of the
compressor and the refrigeration system.
Ensure that a good quality vacuum pump is
used to pull a minimum vacuum of 250
microns (0.25 torr) measured at refrigeration system, and
not at the vacuum pump gauge.
Once pressure testing has been completed, the system needs
to be evacuated to remove any moisture from the piping. This
can be done as follows:
•
Ensure any nitrogen charge is safely released from the
system.
•
Connect a gauge manifold to the connections on the
service valves on the condensing unit.
Low Side, barg (psig)
19 (275)
Page 8
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