System Evacuation & Recharging; Self-Contained Products - Cornelius XAC 1444 Service Training Manual

Xtreme Ice Training Manual
SYSTEM EVACUATION & RECHARGING
Should service work ever be required on a product where the sealed refrigeration is opened for any rea-
son, the refrigerant must be recovered, drier/filter replaced, evacuated and recharged. The old method of
"purging" is NOT ACCEPTABLE. Always evacuate the system through both the high and low side service
valves. Be certain both valves are completely open when evacuating and the drier/filter has been re-
placed.

SELF-CONTAINED PRODUCTS

With the new POE [Polyol Ester] oils, the refrigeration system is more prone to moisture problems than
the CFC systems. Every effort should be made to never have the system open to the atmosphere for
longer than 15 minutes, and the replacement of the drier/filter is no longer an option, [IT IS MANDATO-
RY].
A good vacuum is not always easy to measure, however the goal is to have less then 1% non-condens-
ible vapors in the system at the completion of the evacuation. Basic guidelines with a good pump would
be to evacuate a self–contained product 30 to 45 minutes and a remote product no less than 60 minutes.
The system should be evacuated to approximately 200/250 microns. Then perform a 5 minute holding
test. You may expect a low grade loss of the vacuum as normal. However, a rapid rise to normal atmo-
spheric pressure would signal a system leak is present and must be located and repaired before recharg-
ing the product. A slower pressure rise to approximately 1500 microns would signal moisture still present
in the refrigeration system.
On a "WET" system, it would be beneficial to use heat lamps to raise the temperature of the compressor
dome and evaporator surface area during the evacuation.
To assure a properly recharged product, the refrigerant charge must be weighed into the product using an
electronic charging scale or dial-a-charge. On air- and water-cooled products the charge should be
introduced into the high side service valve. On remote systems, the charge should be introduced into the
product receiver.
OPEN
OPEN
VACUUM
PUMP
CLOSED
FIGURE 14
October 17, 2005
MANIFOLD SET
OPEN
OPEN
HIGH SIDE
SERVICE
VALVE
LOW SIDE
SERVICE
VALVE
CLOSED
CHARGING
CYLINDER
ELECTRONIC
SCALE
OPEN
CLOSED
VACUUM
PUMP
35
MANIFOLD SET
CLOSED
CLOSED
HIGH SIDE
SERVICE
VALVE
LOW SIDE
SERVICE
VALVE
OPEN
CHARGING
CYLINDER
OPEN
ELECTRONIC
SCALE
TP00952