Dunham-Bush MM0305F, Руководство по установке, эксплуатации и обслуживанию

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4.0 OPERATION
4.1 PHASE ROTATION
Avoid running in reverse rotation. If during
initial start up the compressor does not build
up pressure, noise is abnormally loud and
power consumption is minimal, then there is a
possibility that the unit is operating at reverse
rotation. Shut down the power and connect
phase to the proper terminals. Running reverse
may damage the compressor (s).
4.2 CYCLE LIMIT RATE
Each compressors must not be cycle on-off for
more than 12 times per hour. The higher
number of starts per hour will reduce the life of
the compressor. Thus, it is suggested that anti
short cycle timer is provided in the system.
4.3 FAN CYCLING
(OPTIONAL,
STANDARD FOR HEAT
PUMP)
During cooling only, the head pressure control
would allow the unit to operate at lower
ambient temperature by building up the
discharge pressure through cycling of fans (for
single fan unit, this is achievable by reducing
the fan speed). If there is demand for cooling.
The unit would run on cooling until the manual
charge over is set to heating. Please observe
the lowest ambient for cooling mode. For heat
pump units fan cycling is standard.
4.4 DEFROST CYCLE
(STANDARD FOR
HEAT PUMP)
During heating, a defrost controller would
initiate the defrost cycle once there is demand
for it. The sensor from the controller would
sense the suction pressure and if the pressure is
lower then the preset value, Then a signal
would be sent to the control panel which then
relay the signal to the reversing valve to
reverse the cycle. Now, the outdoor coil would
be discharging hot air and defrosting the ice on
the fins surface. The standard factory set timer
for the defrost cycle is 10 minutes which could
be adjusted according to the site condition.
4.5 CRANKCASE HEATER
(STANDARD FOR
HEAT PUMP)
Refrigerant tend to migrate to colder section of
the unit. During winter, the compressor
compartment is at lower temperature than the
evaporator and thus refrigerant tend to
accumulate in the compressor compartment.
Connect power source to the unit a few hours
prior to compressor start up so that the
refrigerant would be forced out of the
compressor compartment. It is good practice to
let the crankcase heater to be energized
continuously, independent of compressor
operation.
4.6 STOP VALVE
Inspect all stop valves prior to start up. They
shall be in open position.
4.7 HYDROPHILIC
CONDENSER COIL
(STANDARD FOR
HEAT PUMP)
Hydrophilic fins assist condensation to be
removed faster and therefore reduced the
possibility of icing on the coil.
4.8 STAINLESS STEEL
BOLTS AND NUTS
Reduce the possibility of corrosion especially
when the environment is corrosive.
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