11 Troubleshooting
Installation manual
15
EKHWS150~300D3V3
Domestic hot water tank with option kit for air to water heat pump
system
4P510672-1C – 2023.02
Chemical disinfection
If the applicable legislation requires a chemical disinfection in
specific situations, involving the domestic hot water tank, please be
aware that the domestic hot water tank is a stainless steel cylinder
containing an aluminium anode. We recommend to use a non-
chloride based disinfectant approved for use with water intended for
human consumption.
NOTICE
When using means for descaling or chemical disinfection,
make sure water quality still complies with EU directive
2020/2184.
Switch box
▪ Carry out a thorough visual inspection of the switch box and look
for obvious defects such as loose connections or defective wiring.
▪ Check for correct operation of contactor K3M by use of an
ohmmeter. All contacts of this contactor must be in open position.
Pressure relief valve hose
Check the condition and routing of the hose. Water must drain
appropriately from the hose.
Booster heater of the domestic hot water tank
It is recommended to remove lime buildup on the booster heater to
extend its life span, especially in regions with hard water. To do so,
drain the domestic hot water tank, remove the booster heater from
the domestic hot water tank and immerse in a bucket (or similar) with
lime-removing product for 24 hours.
11
Troubleshooting
11.1
Overview: Troubleshooting
This chapter describes what you have to do in case of problems.
It contains information about solving problems based on symptoms.
Before troubleshooting
Carry out a thorough visual inspection of the unit and look for
obvious defects such as loose connections or defective wiring.
11.2
Precautions when troubleshooting
DANGER: RISK OF ELECTROCUTION
DANGER: RISK OF BURNING/SCALDING
WARNING
▪ When carrying out an inspection on the switch box of
the unit, ALWAYS make sure that the unit is
disconnected from the mains. Turn off the respective
circuit breaker.
▪ When a safety device was activated, stop the unit and
find out why the safety device was activated before
resetting it. NEVER shunt safety devices or change
their values to a value other than the factory default
setting. If you are unable to find the cause of the
problem, call your dealer.
WARNING
Prevent hazards due to inadvertent resetting of the thermal
cut-out: power to this appliance MUST NOT be supplied
through an external switching device, such as a timer, or
connected to a circuit that is regularly turned ON and OFF
by the utility.
11.3
Solving problems based on
symptoms
11.3.1
Symptom: No water flow from hot taps
Possible causes
Corrective action
The main water supply is OFF.
The cold water inlet pressure
reducing valve is not fitted
properly.
The strainer is blocked.
Turn OFF the water supply,
remove and clean the strainer of
the Inlet control group (field
supply).
The cold water inlet pressure
reducing valve is not fitted
properly.
Check and refit as required.
11.3.2
Symptom: The water from the hot taps is
cold
Possible causes
Corrective action
The thermal cut-out(s) has/have
operated.
Check and reset the button(s).
The unit is NOT operating.
Check unit operation. Refer to
the manual delivered with the
unit. If any faults are suspected,
contact your dealer.
11.3.3
Symptom: Intermittent water discharge
Possible causes
Corrective action
Thermal control failure (water will
be hot).
▪ Turn OFF the power to the
unit.
▪ When discharge has stopped,
check the thermal controls and
replace if faulty.
▪ Contact your local dealer.
The expansion vessel is broken.
Replace the expansion vessel.
11.3.4
Symptom: Continuous water discharge
Possible causes
Corrective action
Cold water inlet pressure.
Check the pressure reducing
valve. Replace the pressure
reducing valve if the measured
pressure is >2.1 bar.
Temperature and pressure relief
valve.
Check and reset button.
The expansion relief valve is not
functioning properly.
Check for correct operation of the
pressure relief valve by turning
the red knob on the valve
counter clockwise:
▪ If you do not hear a clacking
sound, contact your local
dealer.
▪ In case the water keeps
running out of the unit, close
both the water inlet and outlet
shut-off valves first and then
contact your local dealer.
