Operating Principle; Control Functions; Protective Functions - Fujitsu Waterstage WOYG160LJL Installation Manual

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Operating principle

The heat pump transmits the energy contained in the
surrounding air into the dwelling to be heated.
The heat pump consists of four main elements, in which
a refrigerant (R410A) circulates.
- In the evaporator (ref. 13,
The calories are taken from the outside air and
transmitted to the refrigerant. Because it has a low
boiling point, it changes from a liquid to a vapour, even
in cold weather (down to -25°C outside temperature).
- In the compressor (ref. 10,
The vaporised refrigerant is pressurised and takes on
even more calories.
- In the condenser (ref. 14,
The energy of the refrigerant is transmitted to the
heating circuit. The refrigerant returns to its liquid state.
- In the expansion valve (ref. 9,
The liquefied refrigerant is returned to a low pressure
and regains its initial temperature and pressure.
The heat pump is equipped with a controller which
controls the room temperature based on the outdoor
temperature measurement. The room thermostat
(option) provides a corrective action for the temperature
control.
The hydraulic unit is fitted with an electrical backup or
boiler connection which intervenes to provide additional
heat during the coldest periods.
Dwelling heat loss (kW)
8
7
6
Backup
5
4
3
Heat Pump
2
1
0
-20 -15 -10 -5
HP +
electrical
backup
fig. 10 - Examples and operating limits
- 14 -
fig. 8, page
fig. 8, page
fig. 9, page
fig. 8, page
HP power
0 5 10 15 20 25
Outdoor temperature (°C)
Max
authorised HP
start-up temp.
HP only
Outdoor temperature (°C)

• Control functions

- The heating circuit's flow temperature is controlled by
the temperature control.
- Depending
the outdoor unit's power is modulated by the "Inverter"
12):
compressor.
- Control of the backup electrical heating.
- The daily timer program is used to set the periods
where the ambient temperature is comfortable or
12):
reduced.
- Summer/winter time mode switchover is automatic.
- Management of the boiler backup*.
13):
- Room sensor*: The room sensor provides a corrective
action for the temperature control.
- Control of a second heating circuit*.
12):
- Domestic hot water*: Heating timer program.
- Managing cooling*.
* Where the heat pump is fitted with options and associated kits.

• Protective functions

- Anti-legionella cycle for domestic hot water.
- Frost protection: Frost protection cuts in if the heating
circuit's flow temperature falls below 5°C (provided
that the heat pump's electrical power supply is not
interrupted).
46
on the heating flow
Waterstage / Installation / 2011 - EN
temperature,