Automatic Auxiliary Functions - Vaillant geoTHERM VWS 61/2 Operating Manual

These different temperatures are produced in the cool-
ant circuit by means of a compressor (2) and an expan-
sion valve (4), which are situated between the evapora-
tor (1) and the condenser. The coolant flows in vapour
form from the evaporator (1) into the compressor,
where it is compressed. This causes the pressure and
temperature of the coolant vapour to rise sharply. After
this process it flows through the condenser, where it re-
leases its heat to the heating water by condensation. It
flows as a liquid to the expansion valve, where it ex-
pands significantly and in so doing loses much of its
pressure and temperature. This temperature is now
lower than that of the outside air which flows through
the evaporator (1). The coolant can thus take up more
heat in the evaporator, (1) turning into vapour in the
process and flowing to the compressor. The cycle starts
again.
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
coolant circuit are insulated. Should condensate appear,
however, it is collected in a pan and diverted under-
neath it. Drop formation under the unit is thus possible.
4.3

Automatic auxiliary functions

Frost protection
The controller is equipped with a frost protection func-
tion. This function ensures that your heating installation
is protected from frost in all operating modes.
If the outside temperature falls below a value of 3 °C, a
set-back temperature is automatically programmed for
each heating circuit.
Cylinder frost protection
This function starts automatically when the actual tem-
perature of the cylinder falls below 10 °C. The cylinder is
then heated to 15 °C. This function is also active in the
"Off" and "Auto" operating modes, regardless of the
timer programs.
Checking external sensors
The hydraulic basic circuit given by you during commis-
sioning determines the required sensors. The heat pump
constantly checks automatically that all the sensors are
fitted and functioning.
Protection against 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.
Operating Manual geoTHERM VWS/VWW 0020051547_02
Equipment and functional description 4
Pump seizing and valve seizing protection
To prevent the sticking of the heating, circulation and
brine pump or of the hot water diverter valve UV1, the
pumps and the valve, which have not been in operation
for 24 hours, are switched on every day for approx.
20 sec.
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 1.
Floor protection circuit for all hydraulics without
buffer cylinder (e.g. in hydraulic plans 1 and 3)
If the measured flow temperature in the underfloor
heating circuit continuously exceeds a value for more
than 15 minutes, the heat pump switches off and issues
an error message 72. When the heating flow tempera-
ture falls below this value again and the error has been
reset the heat pump switches back on.
Caution!
a
Danger of damage to the floor.
Set the value for the floor protection cir-
cuit ensuring that it is not high enough
to damage the floor as a result of exces-
sively high temperatures.
Phase monitoring
The sequence and existence of phases (clockwise rotat-
ing field) on the 400V voltage supply are continuously
monitored during commissioning and operation. If the
sequence is not correct or if a phase breaks down, the
heat pump is switched off due to the error to avoid
damage to the compressor.
Freezing protection function
The outlet temperature of the heat source is constantly
measured. If the heat source outlet temperature falls
below a specific value, the compressor temporarily
shuts off with the error message 20 or 21. If these er-
rors occur three times in a row there is a fault-induced
shutdown.
For the geoTHERM VWS heat pumps you can set the
value (Default setting -10 °C) for the freezing protection
in the installation assistant A4.
For the geoTHERM VWW heat pumps a default value of
+4 °C is set. This value cannot be changed.
GB 9