Service Manual

25
The vacuum level and vacuum pump may be the same as those for current
refrigerants. However, the rubber hose and gauge manifold to be used for evacuation
and refrigerant charge should be exclusively for POE oils
NOTICE
2) Use an electronic leak detector or soap bubbles to check for leaks. Add a trace of
refrigerant to the system (if using an electronic leak detector), and then raise the
pressure using nitrogen gas (140 PSIG). Do not use R-134a or R-404A as a
mixture with pressurized air for leak testing.
3) For checking leak on R290 System can be use the regular way with a bubble
solution or other leak detector dedicated for combustible gas.
3. Evacuation and Recharge
1) Attach a vacuum pump to the system. Be sure the charging hoses are
connected to low-side access valves.
2) Turn on the vacuum pump. Open the gauge manifold valves. Never allow the
oil in the vacuum pump to flow backwards.
3) Allow the vacuum pump to pull down to a 29.9" Hg vacuum. Evacuating period
depends on pump capacity.
4) Close the low-side valve on the gauge manifold.
5) Disconnect the gauge manifold hose from the vacuum pump and attach it to a
refrigerant service cylinder. Remember to loosen the connection and purge the
air from the hose. See the nameplate for the required refrigerant charge.
Hoshizaki recommends only virgin refrigerant or reclaimed refrigerant which
meets ARI Standard 700 (latest edition) be used.
6) A liquid charge is required when charging an R-134a system. Place the service
cylinder on the scales; if the service cylinder is not equipped with a dip tube,
invert the service cylinder, and then place it on the scales. Open the high-side
valve on the gauge manifold.
7) For R290 is system is recommend to place a nitrogen charge to identify leak
as maximum 200 PSI.
8) Liquid or vapor is possible for R290 be charged.
9) Allow the system to charge with liquid until the proper charge weight is met.