34 | © Danfoss | Produced by Danfoss Redan A/S | 2022.03
145X2068
AQ40514397064001-000101
15.
TROUBLESHOOTING GENERAL
/ TROUBLESHOOTING DHW
In the event of operating disturbances, the following basic features
should be checked before carrying out actual troubleshooting:
• the substation is connected to electricity,
• the strainer on the DH supply pipe is clean,
• the supply temperature of the DH is at the normal level,
• the differential pressure is equal to or higher than the normal
(local) differential pressure in the DH network – if in doubt, ask
the DH plant supervisor.
Authorized personnel only
Assembly, start-up and maintenance work must be per-
formed by qualified and authorized personnel only.
TROUBLE SHOOTING - DOMESTIC HOT WATER
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)
Problem
Possible cause
Solution
Too little or no domestic hot water Dirt strainer in the district heating supply
line clogged.
Clean the dirt 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 defective
- possibly power failure.
Check if the setting of the controller is correct,
- see separate instructions. Check the power sup-
ply; Temporary setting of actuator to “manual”
control - see instructions on heating circuit,
manual control.
Calified plate heat exchanger
Replace
Charging pump pump out of operation or set
too low.
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.
Defective or clogged non-return valve.
Replace or clean
Defective immersion sensor.
Replace sensor.
Calified heat exchanger.
Descale the heat exchanger or replace it
Inadequate cylinder capacity.
Wait for heating / loading of the cylinder.
You may check the specifications of the
manufacturer conc. cylinder capacity.
Long wait for hot water
Circulation pump out of order.
Check whether the pump is running - and wheth-
er there is a power supply to the pump. Make
sure that there is no air in the pump housing.
Temperature too low
See “No domestic hot water”.
See “No domestic hot water”.
Non-return valve on the circulation line defec-
tive (leads to mixing - and the circulation water
pipes become cold during tapping).
Replace non-return valve.
Montage- und Betriebsanleitung / User manual
VXe SLS
