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Danfoss District Energy
VI.HE.M1.02
DKDHR
Instructions for installation and use
VX Solo HWS substations
13.2 Troubleshooting - Domestic hot water
Problem
Possible cause
Solution
No domestic hot water
Defective or wrongly set differential
pressure controller.
Check the functions of the differential
pressure controller - clean valve seat and
capillary tubes if required, - air and rinse
capillary tubes.
Strainer on DH supply clogged.
Clean strainer.
Defective actuator - or possibly dirt in
the valve housing.
Check the functions of the actuator -
clean valve seat if required.
Automatic controls wrongly set or defec-
tive - possibly power failure.
Check if the setting of the controller is
correct, - see separate instructions.
Check the power supply;
Temporary setting of actuator to “manu-
al” control - see instructions on heating
circuit, manual control.
Calified heating element.
Clean DHW cylinder with acid solution or
replace heating element.
Inadequate cylinder capacity.
Wait for heating / loading of the cylinder.
You may check the specifications of the
manufacturer conc. cylinder capacity.
Long waiting time
Circulation pump out of operation.
Check whether the pump is running -
whether the pump is receiving power.
control that there is no air in the pump
housing - see pump manual.
Temperature too low
See “No domestic hot water”.
See “No domestic hot water”.
Non-return valve on the circulation line
defective (leads to mixing - and the
circulation water pipes become cold dur-
ing tapping).
Replace non-return valve.
Temperature too high
Defective actuator - possibly dirt in the
valve housing.
Check the functions of the actuator -
clean valve seat if required.
Automatic controls wrongly set or defec-
tive.
Check if the setting of the controller is
correct, - see separate instructions.
Defective immersion sensor.
Replace immersion sensor.
Variations in temperature
Non-return valve on the circulation line
defective (leads to mixing - and the
circulation water pipes become cold dur-
ing tapping).
Replace non-return valve.
