16
Thermann Installer's Manual
Heat Pump Water Heaters
Troubleshooting
WARNING Electrocution
Troubleshooting must only be carried out by a qualified contractor. Prior to all work on the appliance,
isolate it from the power supply.
!
Material losses
If you disconnect the appliance from the power supply, it is no longer protected against frost or cor-
rosion.
f
f
Only disconnect the appliance from the power supply for longer periods if you are also draining
the hot water cylinder.
f
f
For work inside the appliance, remove the appliance cover (see chapter "Cleaning and maintenance
/ Re-
moving the appliance cover").
f
f
If necessary, remove the upper section of the casing jacket (see chapter "Maintenance and cleaning / Re-
moving the casing ring").
Note
Refit the casing ring after completing the work. See chapter "Maintenance and cleaning / Fitting the
casing ring").
Note
Following an interruption of the power supply, compressor operation remains blocked for at least one
minute while the appliance initialises.
If the compressor subsequently fails to start, it may be blocked by additional safety devices (motor
overload relay, high pressure switch). This block can last between 1 and 10
minutes.
f
f
See chapter "Troubleshooting" in the Owner's Guide.
Fault display in the programming unit
The "service/fault" symbol on the appliance programming unit indicates the occurrence of a fault when it
illuminates or flashes. If the symbol is still illuminated or flashing after 12
hours, please contact the service
department.
A permanently illuminated "service/fault" symbol indicates that a fault has occurred, but the heat pump is
still heating. A flashing "service/fault" symbol indicates that a fault has occurred and the heat pump is no
longer heating.
"Service/
fault"
symbol
Possible causes of fault
Note
Remedy
illumi-
nated
The integral sensor is faulty.
If the integral sensor is faulty, it is set to
the value of the cylinder top sensor, and
amount of mixed water is calculated
using this value. The appliance contin-
ues to deliver heat.
Contact the service department.
The cylinder top sensor is faulty.
The appliance continues to deliver heat. Contact the service department.
Hot gas temperature sensor faulty The appliance limits the set tempera-
ture to 50
°
C.
Contact the service department.
Impressed current anode short
circuit or faulty protective anode
If the impressed current anode is faulty,
the appliance is not protected against
corrosion.
Contact the service department.
No communication between con-
troller and programming unit.
The controller carries on running inde-
pendently.
Contact the service department.
After 70 minutes of defrosting,
the evaporator temperature has
not yet reached 3
°
C. The com-
pressor is not working.
If the fault is continuously displayed, an
air intake temperature outside the ap-
plication limits may be the cause.
The fault is cleared automatically once the
evaporator temperature rises to 3
°
C.
flashes
The cylinder top sensor and the
integral sensor are faulty. The ap-
pliance no longer delivers heat.
The appliance does not permit emer-
gency heating mode.
Contact the service department.
Air intake temperature sensor
faulty
Contact the service department. Activate
emergency heating mode.
Evaporator temperature sensor
faulty
Contact the service department. Activate
emergency heating mode.
The anode current is interrupted.
The appliance does not heat up.
The appliance does not permit emer-
gency heating mode.
Check the impressed current anode and the
wiring.
