Symptom: The Water Pressure Relief Valve Leaks; Symptom: The Space Is Not Sufficiently Heated At Low Outdoor Temperatures; Symptom: The Pressure At The Tapping Point Is Temporarily Unusually High; Symptom: Decoration Panels Are Pushed Away Due To A Swollen Tank - Rotex HPSU Bi-Bloc Ultra Series Installer's Reference Manual

12 Troubleshooting
Possible causes
The valve (if equipped) of the
water circuit towards the
expansion vessel is closed.
The water volume in the
installation is too high
The water circuit head is too high The water circuit head is the
12.3.6 Symptom: The water pressure relief valve
leaks
Possible causes
Dirt is blocking the water
pressure relief valve outlet
12.3.7 Symptom: The space is NOT sufficiently
heated at low outdoor temperatures
Possible causes
The backup heater operation is
not activated
Installer reference guide
88
Corrective action
Open the valve.
Make sure that the water volume
in the installation is below the
maximum allowed value (see
"6.4.3 To check the water volume
rate" [ 4 26] and
and flow
"6.4.4 Changing the pre-pressure
vessel" [ 4 27]).
of the expansion
difference in height between the
indoor unit and the highest point
of the water circuit. If the indoor
unit is located at the highest
point of the installation, the
installation height is considered
0 m. The maximum water circuit
head is 10 m.
Check the installation
requirements.
Corrective action
Check whether the pressure
relief valve works correctly by
turning the red knob on the valve
counterclockwise:
▪ If you do NOT hear a clacking
sound, contact your dealer.
▪ If the water keeps running out
of the unit, close both the
water inlet and outlet shut-off
valves first and then contact
your dealer.
Corrective action
Check the following:
▪ The backup heater operation
mode is enabled.
Go to: [9.3.8]: Installer
settings > Backup heater >
Operation [4‑00]
▪ The backup heater overcurrent
circuit breaker is on. If not, turn
it back on.
▪ The thermal protector of the
backup heater is NOT
activated. If it has, check the
following, and then press the
reset button in the switch box:
▪ The water pressure
▪ Whether there is air in the
system
▪ The air purge operation
Possible causes
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 (applies only to
installations with a domestic hot
water tank)
12.3.8 Symptom: The pressure at the tapping
point is temporarily unusually high
Possible causes
Failing or blocked pressure relief
valve.
12.3.9 Symptom: Decoration panels are pushed
away due to a swollen tank
Possible causes
Failing or blocked pressure relief
valve.
12.3.10 Symptom: Tank disinfection function is
NOT completed correctly (AH-error)
Possible causes
The disinfection function was
interrupted by domestic hot water
tapping
Corrective action
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
"9 Commissioning" [ 4 80].
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]: Installer
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]: Installer
settings > Balancing
Offset BSH setpoint [5‑03]
Corrective action
▪ Flush and clean the complete
tank including the piping
between pressure relief valve
and the cold water inlet.
▪ Replace the pressure relief
valve.
Corrective action
Contact your local dealer.
Corrective action
Program the start-up of the
disinfection function when the
coming 4 hours NO domestic hot
water tapping is expected.
RRGA04~08DAV3 + RHBX04+08DA
ROTEX HPSU Bi-Bloc Ultra
4P495262-1B – 2019.10
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