Instructions for installation and use
Akva Lux II VXe
24 | © Danfoss | Produced by Danfoss Redan A/S | 2021.02
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16. TROUBLE SHOOTING - DOMESTIC HOT WATER
Problem
Possible cause
Solution
DHW*, no hot water
Non-return valve in the circulation pipe
defective (leads to mixing - the circula-
tion water pipes become cold during
tapping).
Replace the non-return valve.
Temperature too low / variations in
temperature
Non-return valve in thermostatic mixer
in the bathroom defective - results in hot
and cold water mixing. Please note that
fluctuating temperatures may occur at
other tapping points in the system!
NB, Check all mixers in the house for
faults/defects!
Replace the mixer or perhaps only the
non-return valve.
Lack of hot water pressure
Clogged strainer in the cold water meter
or possibly in the cold water supply in
the unit.
Calified heat exchanger.
Clean the strainer (cold water meter,
in consultation with the water supply
company).
Replace the heat exchanger.
Long wait for hot water
Circulation pump out of order.
Check whether the pump is running -
and whether there is a power supply to
the pump. Make sure that there is no air
in the pump housing.
No hot water
Dirt strainer in the district heating sup-
ply line clogged.
Defective DHW controller.
Defective sensor. (PTC2)
Clean the dirt strainer.
Check controller settings. You may con-
tact Danfoss Redan A/S for further infor-
mation.
Replace sensor.
Hot water temeprature too low
As above.
Non-return valve in the circulation pipe
defective (leads to mixing - the circulation
water pipes become cold during ).
As above.
Replace non-return valve.
Hot water temperature too high
Defective domestic hot water controller.
Check the function of the DHW control-
ler and replace if defective.
Temperature falls during tapping (lack
of capacity)
Air in the capillary tube for the differen-
tial pressure controller.
Calified plate heat exchanger.
Vent the capillary pipe.
Replace the plate heat exchanger.
Fundamental
In the event of disruptions to operation, you should fundamentally - before commencing the actual troubleshooting - check
whether:
• the system is correctly connected
• the district heating supply temperature is at its normal level
• the differential pressure is at its normal level. Ask your district
heating supplier if necessary
• there is a power supply to the system - pump and automatics
• the dirt strainer in the district heating supply pipe is clean
• there is air in the system (if the system is vented)
