Symptom: Tank Disinfection Function Is Not Completed Correctly (Ah-Error) - Daikin EPRA10EAV3 Installer's Reference Manual

14 | Troubleshooting

14.3.10 Symptom: Tank disinfection function is NOT completed correctly (AH-error)

Installer reference guide
256
Possible causes
The auxiliary boiler is not working
correctly.
The backup heater equilibrium
temperature has not been configured
correctly
There is air in the system.
Too much heat pump capacity is used
for heating domestic hot water
Possible causes
The disinfection function was
interrupted by domestic hot water
tapping
Large domestic hot water tapping
happened recently before the
programmed start-up of the disinfection
function
The disinfection operation was stopped
manually: [C.3] Operation > Tank was
turned off during disinfection.
Corrective action
If an auxiliary boiler is connected
directly to the tank and space heating
support is activated, make sure that:
▪ the boiler is operating correctly.
▪ the boiler capacity is sufficient.
Increase the equilibrium temperature to
activate the backup heater operation at
a higher outdoor temperature.
Go to: [9.3.7]: Installer settings
> Backup heater > Equilibrium
temperature [5‑01]
Purge air manually or automatically. See
the air purge function in the chapter
4
"11 Commissioning" [ 234].
Check if the Space heating
priority settings have been
configured appropriately:
▪ Make sure that the Space heating
priority has been enabled.
Go to [9.6.1]:
settings > Balancing > Space
heating priority [5‑02]
▪ Increase the "space heating priority
temperature" to activate backup
heater operation at a higher outdoor
temperature.
Go to [9.6.3]:
settings > Balancing
Priority temperature [5‑03]
Corrective action
Program the start-up of the disinfection
function when the coming 4 hours NO
domestic hot water tapping is expected.
If in [5.6] Tank > Heat up mode the
mode Reheat only is selected, it is
recommended to program the start-up
of the disinfection function at least
4 hours later than the last expected
large hot water tapping. This start-up
can be set by installer settings
(disinfection function).
Do NOT stop tank operation during
disinfection.
EPRA08~12EAV3+W1 + ETSH/X(B)12P30+50EF
Daikin Altherma 3 H MT ECH₂O
Installer
Installer
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4P663478-1B – 2022.07