J&E Hall JEHSD-0600-M-3, Technical Manual

Page: 12 / 40

Issue: 01.05.2017 Page 12
Installation
Pressure Testing
The condensing units are pressure tested in the factory prior to dispatch. All units come with a holding
charge of oxygen free nitrogen (OFN).
Once the pipework installation is complete, it should be pressure tested prior to evacuation to test for leaks.
A pressure leak test should be carried out using OFN.
NEVER USE OXYGEN FOR PRESSURE TESTING SYSTEMS . 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 PPE as
required.
Always pressurize the system slowly, preferably in stages up to the maximum required pressure. Maximum test pressures
applicable to the unit are as follows:
Listen for any possible leaks and check all joints with bubble spray. If any leaks are discovered, release pressure slowly
from system until empty, repair leak and then restart pressure testing procedure. Never attempt to repair a leak on a
pressurized system.
A strength test should also be incorporated (to installed pipework only) according to local regulations.
Once testing has been completed satisfactorily, release the pressure from the system gradually and safely to external
atmosphere.
Evacuation & Charging
Once pressure testing has been completed, the system can now be evacuated to remove air and 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.
•
Connect a vacuum pump and vacuum gauge to the system.
•
Ensure all gauge manifold and service valves are open as required.
•
Evacuate the system until vacuum is below 250 microns (0.25 torr).
Note: A triple evacuation procedure is recommended for all new systems or where moisture is suspected
Once the system is isolated and the vacuum pump is switched off, any rise in pressure indicates that either there may be a
leak in the system or moisture is still present. In this case, recheck the system for leaks, repair as necessary, and then restart
the evacuation procedure. Once completed satisfactorily, the vacuum pump and vacuum gauge can be removed.
At this point, the refrigerant charge can be added to the system as required. Refrigerants must be charged in the liquid
phase.
Charging of liquid into the suction side of the system should ONLY be done with a metering device. Use
calibrated weighing scales to record the amount of refrigerant added to the system.
Test pressure
High side Low side
28 barG
(405 psiG)
19 barG
(275 psiG)
Important Note:
Moisture prevents proper functioning of the compressor and the refrigeration system. Ensure that a good
quality vacuum pump is used to pull a vacuum below 250 microns (0.25 torr).