Running And Maintenance - Sinclair SCV-50EA Service Manual

15. Running and Maintenance

a) Operating characteristics
Set point in cooling mode
(factory set) = 12°C, Hysteresis = 3°C.
The compressor starts with water temperatures above 12°C.
The compressor shuts down with water temperatures of less than 9°C.
Set point in heating mode
(factory set) = 40°C, Hysteresis = 4°C.
The compressor starts with water temperatures below 38°C.
The compressor shuts down with water temperatures above 42°C.
In the event of a temporary power failure, when power returns, the mode set previously will be retained in the
memory.
Compressor start up delay
Two functions prevent the compressor from starting up too frequently
- Minimum time since last start-up 300 seconds.
Pump
The electronic board includes a pump control output. The pump starts when the assembly is powered up
and at least 285 seconds before the compressor starts up and stops 120 seconds after the assembly shuts
down. After the first 120 seconds of pump operation when the water flow is at full speed, the water flow
alarm functions are activated (differential pressure switch and flow switch). With a pump connected to
terminals PL and PN on the installer terminal board.
Fan speed control
For correct operation of the unit with different outside temperatures, the microprocessor controls the fan
speed based on the pressure reading from the pressure probe, thus enabling heat exchange to be increased
and/or decreased, maintaining the condensing or evaporation temperature practically constant.
The fan functions independently of the compressor.
Frost prevention alarm
To prevent the water freezing and damaging the plate heat exchanger, the microprocessor shuts down the
compressor if the temperature measured by the heat exchanger outlet temperature sensor is less than 3°C.
The frost prevention temperature set point can be modified by an authorized service center only and only
after verifying that the water circuit contains antifreeze. Tripping of this alarm shuts down the compressor but
not the pump, which remains active. To reset normal functions, the outlet water temperature must rise to
more than +15°C. Reset is manual.
Water flow alarm
The microprocessor provides for management of a water flow alarm controlled by a differential pressure
switch fitted as standard on the appliance to be installed on the water delivery piping.
This safety device may trip after the first 120 seconds of pump operation when the water flow is up to speed.
Tripping of this alarm shuts down the compressor but not the pump, which remains active. To reset normal
functions, the alarm contact must be deactivated for at least 15 seconds.
When electrical current exceeds to setting value and condenser temperature over than 62°C, system will
shut down, but not returns to normal operation until the condenser temperature decreased less than 52°C.
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