Hussmann USL-2, Инструкция по установке и обслуживанию

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Page 9
in the liquid line after the condenser and just
ahead of the filter-drier. It has sweat connec-
tions, and is in a horizontal position. The
manufacturer may label the receiver as a muf-
fler or a drier but it is, in fact, an empty shell.
CRANKCASE PRESSURE REGULATOR -
The USL-2 with R404a refrigerant em-
ploys a crankcase pressure regulator in the
suction line. The CPR is set for 12 psi. The
purpose of the valve is to maintain a low suc-
tion pressure on start-up so that the compres-
sor will start properly. On start-up, the valve
will hold the suction pressure at the desired
setting until the suction pressure has dropped
below the setting, then the valve will open.
If it becomes necessary to check or reset
the setting, the case must be warm such as af-
ter a defrost cycle or from an initial warm
case condition. Put a suction compound gauge
on the compressor suction valve, start the com-
pressor. If the pressure needs to be reduced
turn the adjustment screw clockwise or, coun-
terclockwise to raise the pressure. DO NOT
SET THE VALVE BASED ON THE NAME-
PLATE AMPERAGE RATING AS THE
PRESSURE SETTING WILL BE TOO HIGH
AND THE COMPRESSOR WILL NOT
START PROPERLY.