4.6 Power limitation
The frequency converter (FC) is continuously sensing the condensing pressure via the high pressure
sensor (HPT) and gradually slows down the speed of the compressor, if the pressure exceeds the set
limitation value. This is done to avoid a high pressure alarm.
4.7 Components and function
4.7.1 Compressor
The compressor in Living HP is a high-efficiency, variable speed scroll compressor. It is designed especially
for speed control and can not run without frequency converter. Speed and by that cooling capacity is
regulated by changing the operating frequency, the maximum working range of the compressor is no less
than 20 to 120 rps (revolutions per second). In the smaller unit sizes the maximum frequency is limited via
a setting in the frequency converter. Controlling of the compressor is completely automatic according to
the need of the premises and the signal comes via the control unit Carel to the frequency converter.
4.7.2 Compressor protection
The compressor is protected by the following:
•
High pressure switch in the high pressure side (HPZ)
•
Low pressure switch on the low pressure side (LPZ)
•
Refrigerant discharge gas temperature sensor (HTT)
• If any of the above protections are triggered the unit will be stopped and cause will be displayed in the
alarm screen. Manual acknowledgment and reset must be done before the compressor can start again.
4.7.3 Frequency converter
The frequency converter of the compressor is located in the electrical cabinet. The programmable
controller receives a control signal corresponding to the current heating load from the control unit Carel
and then, via frequency converter, regulates the compressors speed according to the actual heating
load. The programmable controller has also a high pressure sensor (HPT) connected. This sensor
continuously measuring the pressure in the heating system. If the pressure exceeds the set value in the
programmable controller the output frequency is reduced and thereby the compressors speed will be
reduced so that the pressure will not rise to the level were the high pressure switch (HPZ) on the high
pressure side will trigger. The compressor is protected from fast start and stops by an restart delay
function in the programmable controller.
4.7.4 Refrigerant
The refrigerant is of type R410 A, the system comes pre-filled and tested at the factory. On top of the
Living HP are the high and low pressure side measuring points (tappings). Concerning the control and
reporting of the refrigerant installation, see chapter .
4.7.5 Condenser and Evaporator
The evaporator coil is made of copper tubes with aluminium fins and is used to absorb heat from extract
air. A brazed plate heat exchanger is used as a condenser to transfer heat to the water system. The
condenser is made of stainless steel plates brazed together with every plate turned 180 degrees in
opposition to each other. This design creates two highly turbulent fluid channels that flow in opposite
directions over a massive surface area.
Operation and Maintenance Instructions
209531
8
Systemair AB
