Vaillant geoTHERM Installation And Maintenance Instructions

Appendix
38 Installation and maintenance instructions geoTHERM 0020250180_00
Code
Meaning Cause
Remedy
F.735
Evaporation temperature too high – Temperature in the environment cir-
cuit (heating mode) or building cir-
cuit (cooling mode) too high for com-
pressor operation
– Feed-in of external heat into the en-
vironment circuit
– Reduce or stop the external heat
that is entering
– Check the de-icer (does it heat
up even though it is "Off" in the
sensor/actuator test?)
– Check the EEV (does the EEV
move to the limit stop? Use the
sensor/actuator test)
– Check the compressor inlet
sensor and low-pressure sensor
F.740
Environment cir. inlet temperature too low – Inlet temperature in the environment
circuit too low for the compressor to
start
Heating:
– VWS environment circuit inlet tem-
perature < -10 °C
– Check the dimensioning of the
environment circuit for VWS
– Check the sensors
F.741
Building circuit inlet Return temperature too
low
– Return temperature in the building
circuit too low for the compressor to
start
Heating:
– Return temperature < 5 °C
Cooling:
– Return temperature < 7 °C
– Check the sensors
– Checking the cooling mixer
F.742
Environment cir. inlet temperature too high – Inlet temperature in the environment
circuit too high for the compressor to
start
Heating:
– Environment circuit inlet temp. > 25
°C
– Check the environment circuit
– Check the sensors
– Checking the environment circuit
pump
– Checking the cooling mixer
– Checking the isolation valve
in the environment circuit (if
present)
F.743
Building circuit inlet Return temperature too
high
– Return temperature in the building
circuit too high for the compressor to
start
Heating:
– Return temperature > 55 °C
Cooling:
– Return temperature > 35 °C
– Check the sensors
– Checking the heating pump
– Checking the non-return flap (if
present)
– Checking the 2-zone set (if
present)
F Sensor characteristics for the VR 10 external temperature sensor
Temperature (°C) Resistance (ohms)
-40 87879
-35 63774
-30 46747
-25 34599
-20 25848
-15 19484
-10 14814
-5 11358
0 8778
5 6836
10 5363
15 4238
20 3372

Vaillant geoTHERM Specifications

General

Brand	Vaillant
Model	geoTHERM
Category	Heat Pump
Language	English