Operation Mode Of The Coolant Circuit; Automatic Auxiliary Functions - Vaillant geoTHERM VWS Serie Instrucciones De Uso

3 Equipment and functional description
3.2

Operation mode of the coolant circuit

Cold water
Heating system
Additional
heating
Switching valve
Heating water pump
3
Condenser
Expansion valve
Compressor
4
Evaporator
1
Brine pump
Heat source
Fig. 3.2 Principle of operation of the heat pump
The coolant circuit is connected by means of the evapo-
rator (1) to the environmental heat source, from which it
extracts thermal energy. At the same time, the physical
state of the coolant changes; it evaporates. The coolant
circuit is connected by means of the condenser (3) to
the heating system, to which it releases the heat again.
In so doing, the coolant becomes liquid again; it con-
denses.
As thermal energy can only pass from a body at a high-
er temperature to a body at a lower temperature, the
coolant in the evaporator must have a lower tempera-
ture than the environmental heat source. On the other
hand, the temperature of the coolant in the condenser
must be higher than that of the heating water in order
to be able to release the heat to it.
These different temperatures are produced in the cool-
ant circuit by means of a compressor (2) and an expan-
sion valve (4) between the evaporator and condenser.
The coolant flows in vapour form from the evaporator
into the compressor, where it is compressed. This caus-
es the pressure and temperature of the coolant vapour
to rise sharply. After this process it flows through the
condenser, where it releases its heat to the heating
water by condensation. It flows as a liquid to the expan-
sion valve, where it expands significantly and in so doing
loses much of its pressure and temperature. This tem-
perature is now lower than that of the brine flowing
through the evaporator. The coolant can thus take up
more heat in the evaporator, turning into vapour in the
process and flowing to the compressor. The cycle starts
again.
6
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If required, the electric auxiliary heating can be
switched in by the integrated controller.
To prevent the formation of condensate in the interior
of the unit, the pipes of the heat source circuit and the
Hot water
coolant circuit are insulated. In the unlikely event that
condensate forms, this collects in a condensate pan in-
side the unit and is discharged under the unit where a
suitable condensate drain should be installed.
Domestic
3.3
hot water cylinder
Frost protection
The controller is equipped with a frost protection func-
Heating water circuit
tion. This function ensures that your heating installation
is protected from frost in all operating modes.
The set-back temperature is pre-set automatically for
each heating circuit if the outside temperature falls
2
Coolant circuit below 3 °C.
Cylinder frost protection
This function starts automatically when the actual tem-
perature of the cylinder falls below 10 °C. The cylinder is
Heat source circuit
then heated to 15 °C. This function is also active in the
"Off" and "Auto" operating modes, regardless of the
timer programmes.
Checking the external sensors
The hydraulic basic circuit given by you during commis-
sioning determines the required sensors. The heat pump
constantly checks automatically that all sensors are in-
stalled and functioning.
Protection from loss of heating water
An analogue pressure sensor monitors possible low
water pressure and switches the heat pump off if the
water pressure on the pressure gauge reads less than
0.5 bar and switches it back on when the water pressure
is over 0.7 bar on the pressure gauge.
Pump seizing and valve seizing protection
To prevent the heating, circulation or brine pumps, or
the hot water diverter valve UV1, from seizing, those
pumps and the valve that have not been in operation for
the last 24 hours are turned on in sequence for approxi-
mately 20 seconds every day.
Protection against loss of brine (VWS only)
An analogue pressure sensor monitors possible low
brine pressure and switches the heat pump off if the
brine pressure is ever less than 0.2 bar on the pressure
gauge and error 91 is displayed on the error memory.
The heat pump switches on again when the brine pres-
sure rises above 0.4 bar gauge pressure.
If the brine pressure drops below 0.6 bar on the pres-
sure gauge for more than one minute a warning appears
in menu

Automatic auxiliary functions

1.
Operating Manual geoTHERM VWS/VWW 0020051578_01