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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 period provided the
frost protection function (which depends on the out-
side 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 re-
heated 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 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 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
then heated to 15 °C. This function is also active in the
geoTHERM exclusive VWS 0020051614_00 installation instructions
"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 pres-
sure 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
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 (in hydraulic plan 6)
If the heating flow temperature in the underfloor heat-
ing circuit measured by sensor VF2 continuously ex-
ceeds a value of (max. HK temp. + compressor hystere-
sis + 2 K, default setting: 52 °C) for longer than 15 min-
utes, the heat pump switches off with error message
F.72 (see Chap. 10.6). When the heating flow tempera-
ture falls below this value again and the error has been
reset the heat pump switches back on.
The maximum heating flow temperature can be changed
via vrDIALOG with the "Maximum heating circuit tem-
perature" parameter.
a
Caution!
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.
Controller 8
49
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