12 Troubleshooting
Installer reference guide
78
RRLQ004~008CA + RHBH/X04+08CB
ROTEX HPSU low temperature Bi‑bloc
4P384979-1C – 2017.04
▪ Using an ohmmeter, check if contactors K1M, K2M, K3M and K5M
(depending on your installation) operate correctly. All contacts of
these contactors must be in open position when the power is
turned OFF.
WARNING
If the internal wiring is damaged, it has to be replaced by
the manufacturer, its service agent or similarly qualified
persons.
Booster heater of the domestic hot water tank
INFORMATION
Only for wall-mounted units equipped with a domestic hot
water tank with a built-in electrical booster heater (RKHW).
It is recommended to remove lime buildup on the booster heater to
extend its life span, especially in regions with hard water. To do so,
drain the domestic hot water tank, remove the booster heater from
the domestic hot water tank and immerse in a bucket (or similar) with
lime-removing product for 24 hours.
12
Troubleshooting
12.1
Overview: Troubleshooting
This chapter describes what you have to do in case of problems.
It contains information about:
▪ Solving problems based on symptoms
▪ Solving problems based on error codes
Before troubleshooting
Carry out a thorough visual inspection of the unit and look for
obvious defects such as loose connections or defective wiring.
12.2
Precautions when troubleshooting
WARNING
▪ When carrying out an inspection on the switch box of
the unit, always make sure that the unit is disconnected
from the mains. Turn off the respective circuit breaker.
▪ When a safety device was activated, stop the unit and
find out why the safety device was activated before
resetting it. NEVER bridge safety devices or change
their values to a value other than the factory default
setting. If you are unable to find the cause of the
problem, call your dealer.
DANGER: RISK OF ELECTROCUTION
WARNING
Prevent hazard due to the inadvertent resetting of the
thermal cut-out: this appliance must NOT be supplied
through an external switching device, such as a timer, or
connected to a circuit that is regularly turned ON and OFF
by the utility.
DANGER: RISK OF BURNING
12.3
Solving problems based on
symptoms
12.3.1
Symptom: The unit is NOT heating or
cooling as expected
Possible causes
Corrective action
The temperature setting is NOT
correct
Check the temperature setting on
the remote controller. Refer to
the operation manual.
The water flow is too low
Check and make sure that:
▪ All shut-off valves of the water
circuit are completely open.
▪ The water filter is clean. Clean
if necessary.
▪ There is no air in the system.
Purge air if necessary. You
can purge air manually (see
"To perform a manual air
purge" on page 74
) or use the
automatic air purge function
(see
"To perform an automatic
air purge" on page 74
).
▪ The water pressure is >1 bar.
▪ The expansion vessel is NOT
broken.
▪ The resistance in the water
circuit is NOT too high for the
pump (see the ESP curve in
the "Technical data" chapter).
If the problem persists after you
have conducted all of the above
checks, contact your dealer. In
some cases, it is normal that the
unit decides to use a low water
flow.
The water volume in the
installation is too low
Make sure that the water volume
in the installation is above the
minimum required value (see
"6.4.3 To check the water volume
and flow rate" on page 25
).
12.3.2
Symptom: The compressor does NOT
start (space heating or domestic water
heating)
Possible causes
Corrective action
The unit must start up out of its
operation range (the water
temperature is too low)
If the water temperature is too
low, the unit uses the backup
heater to reach the minimum
water temperature first (15°C).
Check and make sure that:
▪ The power supply to the
backup heater is correctly
wired.
▪ The backup heater thermal
protector is NOT activated.
▪ The backup heater contactors
are NOT broken.
If the problem persists after you
have conducted all of the above
checks, contact your dealer.
