CU/CFCU
Condensing Units
14
Condensing Units
Installation & Maintenance Manual : 6259626 IM V1.6.0 04/16
Refrigeration Information
PIPEWORK INSTALLATION
General
Special consideration should be given to vertical pipe runs and heat pump installation.
Unit performance will reduce if there are vertical rises of above 5m. Please consult
Airedale Service for risers above 10m.
When insulating refrigerant lines, cut approximately 30 - 50cm longer than the distance
between the units to ensure the insulation goes right upto the unit. Leave connections
uncovered for leak testing.
Remove burrs to the ends of the copper tube, holding the tube downward to avoid
allowing dirt to contaminate the tube.
Where applicable insert flare nuts removed from the pipework terminations and make a
flare at the end of the copper tube to conform with the following:
Inside surface is glossy and smooth
Tapered sides are of uniform length
Refrigeration lubrication is applied to matching surfaces
The installation of a sight glass close to the indoor unit is recommended.
Where applicable braze incoming pipe to rotalock service valve.
PRESSURE TESTING
When installation is complete, the system should be pressure tested.
Fill the system with dry nitrogen to a pressure of between 17 bar/250psig and 34bar/
500 psig.
NOTE: The LP switch if fitted must be disconnected for pressures above
17bar/250 psig.
Record the pressure over a minimum of 60 minutes to detect major leaks (a 24 hour
period should preferably be allowed).
If a reduction in pressure is detected, trace the leak and repair before conducting a further
pressure test and charging.
EVACUATION
Evacuation for systems operating with R407C refrigerant to be carried out as follows (for
alternative refrigerants please refer to Airedale).
Use a high vacuum pump and connect to the high and low pressure sides of the system
via a gauge manifold fitted with compound gauges. A high vacuum gauge should be fitted
to the system at the furthest point from the vacuum pump.
Triple evacuation should be used to ensure that all contaminants are removed.
Operate the vacuum pump until a pressure of 1.5 torr (200 Pa) absolute pressure is
reached, then stop the vacuum pump to break the vacuum using oxygen free Nitrogen
until the pressure rises above zero.
The above operation should be repeated a second time.
The system should then be evacuated a third time but this time to 0.5 torr
absolute pressure.
Break with the correct refrigerant, until pressures equalise between the charging bottle
and the system.
ALTERNATIVE
REFRIGERANTS
If an alternative refrigerant is to be used, this must be with the approval of Airedale
International Air Conditioning Ltd in order for the warranty to be valid.
Care must be taken to ensure that the refrigerant and compressor oil are compatible.
