Controller; Operating Modes And Functions; Automatic Auxiliary Functions - Vaillant geoTHERM VWS Series Installation Instructions Manual

8 Controller

8 Controller
To operate the heat pump economically, it is important
to match the control system to the customer's heating
system and to the pattern of use.
In the following chapter, all the functions of the weath-
er-controlled energy balance controller will be ex-
plained.
8.1

Operating modes and functions

There are five operating modes available for the heating
circuit:
– Auto: the operation of the heating circuit alternates
between the "Heating" and "Energy saving" modes in
accordance with a preset timer programme.
– Eco: the operation of the heating circuit alternates
between the "Heating" and "Off" modes in accordance
with a preset timer programme. The
heating circuit is switched off during the set-back peri-
od provided the frost protection function (which de-
pends on the outside
temperature) is not activated.
– Energy saving: the heating circuit is operated at the
set-back temperature independently of any preset
timer programme.
– Heating: the heating circuit is operated at the flow
temperature setpoint independently of any preset
timer programme.
– Off: the heating circuit is out of operation, provided
that the frost protection function (which depends on
the external temperature) is not activated.
The "Auto", "On and "Off" operating modes are availa-
ble for connected domestic hot water cylinders:
– Auto: the commands for recharging the cylinder or
enabling the circulating pump are given according to a
preset timer programme.
– On: recharging is constantly enabled, i.e. the cylinder
is immediately re-heated when needed, and the circu-
lating pump is constantly in operation.
– Off: the cylinder is not heated and the circulation
pump is not in
operation. Only when the storage tank temperature
falls below 10 °C is the storage tank reheated to 15 °C
for frost protection reasons.
8.2

Automatic auxiliary functions

Frost protection
The controller is equipped with a frost protection func-
tion. This function ensures that the heating system 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 below 3 °C.
Cylinder frost protection
This function starts automatically if the current DHW
temperature falls below 10 °C. The cylinder is then heat-
44
ed to 15 °C. This function is also active in the "Off" and
"Auto" operating modes, regardless of the timer pro-
grammes.
Checking the external sensors
The necessary sensors are configured using the basic
hydraulic circuit that you specified during the initial
commissioning. The heat pump constantly checks auto-
matically that all sensors are installed and functioning.
Protection from loss of heating water
An analogue pressure sensor monitors for any potential
loss of water and switches the heat pump off if the
water pressure is below 0.5 bar gauge pressure, and on
again when the water pressure is above 0.7 bar gauge
pressure.
Pump blocking and valve blocking 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 for any loss of
brine and switches the brine pump off if the brine pres-
sure falls even once below 0.2 bar gauge pressure and
Error 91 is displayed in the error memory.
The heat pump switches on again when the brine pres-
sure rises above 0.4 bar gauge pressure.
A warning message appears in Menu
pressure falls below 0.6 bar gauge pressure for longer
than one minute.
Floor protection switching for all hydraulic systems
without a buffer cylinder (e.g. for Hydraulic Plans
1 and 3)
If the heating flow temperature in the underfloor
heating circuit measured by sensor VF2 continuously
exceeds a value of (max. HK temp. + compressor
hysteresis + 2 K, default setting: 52 °C) for longer than
15 Minuten, the heat pump switches off with error mes-
sage F.72 (see Chap. 10.6). The heat pump switches on
again when the flow temperature has fallen below this
value and the error has been reset.
The maximum heating flow temperature can be changed
via vrDIALOG with the "Maximum heating circuit tem-
perature" parameter.
a
Caution!
Risk of damage to the floor.
Only set the value for the floor protec-
tion circuit high enough that heated
floors are not damaged by excessively
high temperatures.
Installation instructions geoTHERM VWS/VWW 0020057444_01
1 if the brine