Hoshizaki Steelheart Series Service Manual page 37

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.
2) Turn on the vacuum pump, then open the high-side valve on the gauge manifold. 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 high-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 the requirements of ARI
Standard 700 (latest edition) be used.
4. Recharge
6) R-290 can be charged in either the liquid or vapor state.
Liquid charge is preferred. If refrigerant charging is done in the liquid state, place the
service cylinder on the scales; if the service cylinder is not equipped with a dip
tube, invert the service cylinder, then place it on the scales. Open the high-side
valve on the gauge manifold.
7) Allow the system to charge with liquid until the proper charge weight is met.
8) Close the high-side valve on the gauge manifold. If charging is complete, skip to step 10.
9) If necessary, add any remaining charge to the system through the low-side.
NOTICE! To prevent compressor damage, use a throttling valve or liquid
dispensing device to add the remaining liquid charge through the low-side
refrigerant access valve with the compressor running. Close the refrigerant
cylinder valve and let the low-side refrigerant equalize to the system, then close the
low-side manifold gauge. Move the power switch to the "OFF" position (if applicable) or
unplug the appliance from the electrical outlet.
10) Pinch off (crimp down) the process tubes just below the piercing valves.
11) Remove the piercing valves. Cut the process tubes to remove the piercing valve holes
then braze the process tubes closed. Note: Be sure there is no refrigerant leak before
brazing.
12) Use a combustible gas leak detector or soap bubbles to check for leaks again.
13) Place red sleeves over the process tubes.
14) Plug the appliance back into the electrical outlet.
IMPORTANT
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