Filter
Top Products
36
7) Evacuation, Vacuum Pump and Refrigerant Charge [R404A]
Never allow the oil in the vacuum pump to flow backward. The vacuum level and vacuum
pump may be the same as those for the current refrigerants. However, the rubber hose
and gauge manifold to be used for evacuation and refrigerant charge should be exclusively
for R404A.
8) Refrigerant Leak Check
Refrigerant leaks can be detected by charging the unit with a little refrigerant, raising the
pressure with nitrogen and using an electronic detector. Do not use air or oxygen instead
of nitrogen for this purpose, or rise in pressure as well as in temperature may cause
R404A to suddenly react with oxygen and explode. Be sure to use nitrogen to prevent
explosion.
[b] REFRIGERANT RECOVERY
The icemaker unit is provided with refrigerant access valves. Using proper refrigerant
practices, recover the refrigerant from the access valves and store it in an approved
container. Do not discharge the refrigerant into the atmosphere.
[c] EVACUATION AND RECHARGE
1) Attach a vacuum pump to the system. Be sure to connect charging hoses to both high
and low-side access valves.
2) Turn on the vacuum pump. Open the service manifold valves. Never allow the oil in the
vacuum pump to flow backwards.
3) Allow the vacuum pump to pull down to a 760 mmHg vacuum. Evacuating period
depends on pump capacity.
4) Close the low-side valve and high-side valve on the service manifold.
5) Disconnect the vacuum pump and attach a refrigerant service cylinder to the high-side
line. Remember to loosen the connection and purge the air from the hose. For air-cooled
and water-cooled models, see the nameplate for the required refrigerant charge.
6) A liquid charge is recommended for charging an R-404A system. Invert the service
cylinder and place it on scales. Open the high-side valve on the service manifold.
7) Allow the system to charge with liquid until the proper charge weight is met.
8) If necessary, add any remaining charge to the system through the low-side. Use a
throttling valve or liquid dispensing device to add the remaining liquid charge through the
low-side access port with the unit running.
9) Close the service manifold valves and disconnect the service manifold hoses.
10) Cap the access valves to prevent a possible leak.