Symptom 7: Space heating capacity shortage at low outdoor
temperatures
P
OSSIBLE CAUSES
Backup heater operation is not
activated.
The backup heater equilibrium
temperature has not been
configured correctly.
Too much heat pump capacity is
used for heating domestic hot water
(applies only to installations with a
domestic hot water tank).
RKHBH/X008AA
Indoor unit for air to water heat pump system
4PW50203-1A
C
ORRECTIVE ACTION
Check that the "backup heater
operation status" field setting [4-00]
is turned on, see "Field settings" on
page 17.
Check whether or not the thermal
protector of the backup heater has
been activated (refer to Main
components, "Backup heater
thermal protector" on page 6 for
location of the reset button).
Check if booster heater and backup
heater are configured to operate
simultaneously (field setting [4-01],
see "Field settings" on page 17)
Check whether or not the thermal
fuse of the backup heater is blown
(refer to "Main components",
"Backup heater thermal fuse" on
page 6 for location of the reset
button).
Raise the 'equilibrium temperature'
field setting [5-01] to activate backup
heater operation at a higher outdoor
temperature.
Check that the 'space heating
priority temperature' field settings
are configured appropriately:
• Make sure that the "space heating
priority status" field setting [5-02] is
enabled.
• Raise the 'space heating priority
temperature' field setting [5-03] to
activate booster heater operation at a
higher outdoor temperature.
Error codes
When a safety device is activated, the user interface LED will be
flashing, and an error code will be displayed.
A list of all errors and corrective actions can be found in the table
below.
Reset the safety by turning the unit OFF and back ON.
Instruction to turn the unit OFF
User interface mode
Domestic water
(heating/cooling =)
heating mode (w)
ON
ON
ON
OFF
OFF
ON
OFF
OFF
In case this procedure for resetting the safety is not successful,
contact your local dealer.
Error
code
Failure cause
Inlet water temperature
80
thermistor failure (inlet water
thermistor broken)
Outlet water temperature
81
thermistor failure (outlet water
temperature sensor broken)
Water heat exchanger freeze-up
89
failure (due to water flow too low)
Water heat exchanger freeze-up
failure (due to refrigerant
shortage)
Flow failure (water flow too low
7H
or no water flow at all, minimum
required water flow is 12 l/min)
Outlet water temperature of
8H
indoor unit too high (>65°C)
Indoor unit PCB defective
A1
Too low (during cooling
A5
operation) or too high (during
heating operation) refrigerant
temperature (measured by R3T)
Push the y
Push the
v button
button
1 time
1 time
1 time
—
—
1 time
—
—
Corrective action
Contact your local dealer.
Contact your local dealer.
Refer to error code 7H.
Contact your local dealer.
• Check that all shut off valves of
the water circuit are completely
open.
• Check if the water filter needs
cleaning.
•
Check that the unit is
operating within its operating
range (refer to
"Technical
).
specifications" on page 29
• Also refer to "Charging water" on
page 11.
• Make sure there is no air in the
system (purge air).
• Check on the manometer that
there is sufficient water
pressure. The water pressure
must be >0.3 bar (water is cold),
>>0.3 bar (water is hot).
• Check that the pump speed
setting is on the highest speed.
• Make sure that the expansion
vessel is not broken.
• Check that the resistance in the
water circuit is not too high for
the pump (refer to "Setting the
pump speed" on page 17).
• If this error occurs at defrost
operation (during space heating
or domestic water heating),
make sure that the backup
heater power supply is wired
correctly and that fuses are not
blown.
• Check that the pump fuse (FU2)
and PCB fuse (FU1) are not
blown.
• Check that the contactor of the
electric backup heater is not
short circuited.
• Check that the outlet water
thermistor is giving the correct
read out.
Contact your local dealer.
Contact your local dealer.
Installation manual
27