Midea MGC-F05W/N1, Руководство пользователя

Страница: 78 / 94

Running and Maintenance MCAC-TSM-2008-02
76 Installation
7. Running and Maintenance
7.1 Operating characteristics
Set point in cooling
(factory set) = 10°C, Hysteresis = 3°C.
The compressor starts with water temperatures above 13°C.
The compressor shuts down with water temperatures of less than 10°C.
Set point in heating
(factory set) = 45°C, Hysteresis = 3°C.
The compressor starts with water temperatures below 42°C.
The compressor shuts down with water temperatures above 45°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 shut-down 180 seconds.
- Minimum time since last start-up 360 seconds.
Pump
The electronic board includes a pump control output. The pump starts when the assembly is powered up
and at least 120 seconds before the compressor starts up and stops 120 seconds after the assembly shuts
down. After the first 120 seconds o f 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 centre 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 five seconds.
When electrical current exceeds to setting value and condenser temperature over than 65°C, system will
shut down, but not returns to normal operation until the condenser temperature decreased less than 52°C. If
phase sequence were detected error, please re-input power, and then the system will turn normal.