24 | © Danfoss | Produced by Danfoss Redan A/S | 2020.06
13.
TROUBLESHOOTING GENERAL
/ TROUBLESHOOTING DHW
Problem
Possible cause
Solution
Too little or no DHW.
Strainer in supply or return line clogged.
Clean strainer(s).
DHW circulation pump out of order or with
too low setting. (only if DHW circulation
is installed).
Check circulation pump.
Defective or clogged non-return valve.
Replace – clean.
No electricity. Only if station are with DHW
circulation.
Check.
Scaling of the plate heat exchanger.
Replace – rinse out.
Defective temperature sensors.
Check – replace.
Defective controller.
Check – replace.
Hot water in some taps but not in all.
DCW is being mixed with the DHW, e.g. in
a defective thermostatic mixing valve.
Check – replace.
DHW circulation pump out of order or with
too low setting. (only if DHW circulation
is installed).
Replace – clean.
Tap temperature too high; DHW tap load
too high.
Thermostatic valve adjusted to a too high
level. Thermostat is defect.
Check – set – replace.
Temperature drop during tapping.
Scaling of the plate heat exchanger.
Replace – rinse out.
Larger DHW flow than the flat station has
been designed for.
Reduce DHW flow.
In the event of operating disturbances, the following basic features
should be checked before carrying out actual troubleshooting:
• the flat station is connected to electricity,
• the strainer on the HS supply pipe is clean,
• the supply temperature of the HS is at the normal level,
• the differential pressure is equal to or higher than the normal
(local) differential pressure in the HS network – if in doubt, ask
the HS plant supervisor.
Authorized personnel only
Assembly, start-up and maintenance work must be per-
formed by qualified and authorized personnel only.
User manual
EvoFlat Four-Pipe System
