Technical information

UGH021/0301 VL Series Portable Chillers, 2 to 40 Tons
Page: 29
4.6 HIGH PRESSURE
A. If the refrigerant high pressure safety switch has opened, this switch
must be manually reset after the problem has been resolved.
B. Refrigerant high pressure will vary with ambient temperature from a
minimum of 190 psi to as high as 280 psi. Check for restricted
filters, broken or loose blower drive belts, restricted air flow.
C. On air-cooled models: maintain at least four feet of clearance for
each condenser intake.
D. On air-cooled models: check if the discharge duct work (if installed)
is undersized and restricting air flow.
4.7 LOW PRESSURE
A. If the refrigerant low pressure safety switch has opened, the cause
of the problem must isolated and resolved.
B. The switch will automatically reset when the pressure rises above
the cut-in pressure. If this does not occur contact the Conair service
department for instructions.
C. The low pressure switch is set to cut-out at 58 psi and cut-in at 63
psi. If a low pressure condition exists for more than five seconds the
compressor will stop and a “L-P” fault will appear in the display
window.
D. After the refrigerant pressure rises above the cut-in pressure, a three
minute time delay will occur before the compressor restarts. This
will protect the evaporator and compressor from damage should a
problem occur in the refrigeration system or if the chiller is
operated under circumstances which could cause damage to the
refrigeration system.
E. If a low pressure fault occurs, check for blockage in the evaporator
water inlet. If a blockage is found, back flush the evaporator and
flush complete process water system.
F. Check for low freon. The refrigerant sight glass should appear clear
when the unit is operating at 100% cooling capacity. Constant
foam or bubbles indicate a loss of freon.
G. Check to see if the condensing media is too cold. On air condensed
units, the ambient air at the condenser intake must be at least
60°F. If this is not possible, a damper control assembly package may
be required.
4.8 FREEZESTAT
A. The freezestat sensor bulb is located at the evaporator water outlet