Electrical Connections; Working Limits - HL -i Series Use And Maintenance Handbook

ELECTRICAL CONNECTIONS

Check power supply against name plate data on the unit (voltage, frequency, phase number). Relevant regulations
must be strictly adhered to.
Use a power supply cable whose section shall not be smaller than the value indicated in the wiring diagrams
appendix "C") and whose length shall be moderate to ensure there won't be excessive voltage drops.
Upstream cable shall be protected by means of an automatic circuit breaker or of three fuses whose nominal current
is equal to that of the unit's main disconnecting switch inside the unit's electric panel.
The breaking power of these elements must be at least equal to the maximum short-circuit current which is
generated if a failure occurs in the place where the unit is installed.

WORKING LIMITS

The water flow rate supplied by the unit is related to a 5°C temperature jump between input and
output which depends on the supplied cooling power. The maximum allowable flow rate entails a 3°C
jump ( higher flow rates may cause too high evaporating temperatures and damage the evaporator ).
The minimum allowable flow rate entails a 7°C jump (lower flow rates may cause too low evaporating
temperatures, as a consequence the safety devices would be tripped and the unit would stop).
COOL WATER TEMPERATURE:
The minimum outlet temperature of evaporator is 5°C not included "brine" versions (*); the
maximum inlet temperature to the evaporator is 30°C.
( * ) : Operation with low- temperature water:
If the cool water temperature is lower than 4°C (out of the evaporator) a water-ethyl glycol mixture
should be used (see table below).The antifreeze thermostat(always 3-5°C above the mixture freezing
point), the operating thermostat and the set point (4°C above the desired water temperature out of the
evaporator) must also be set to new values.
OPERATION WITH WATER-ETHYL GLYCOL MIXTURE
DESCRIPTION
FREEZING
TEMPERATURE
PERCENTAGE OF ETHYL-GLYCOL OUT OF MIXTURE
5% 10% 15%
-2.1℃ -4.5℃ -7℃
5
WEIGHT
20% 25% 30%
-10℃ -13℃ -17℃ -21℃
(see
35% 40%
-25℃