6 720 680 174 (2014/05)
Therm 8000S
Problem solving | 41
10 Problem solving
10.1 Problem/Cause/Solution
To remove error code from the display, press
the reset button.
Display
Cause
Solution
Fault in the flue gas limiter.
Temperature above 110 °C
inside the cabinet.
1. Check continuity of the flue gas limiter (normally closed).
2. Check for flue gas leakage around the top and bottom seals of heat
exchanger, use mirror to check around the rear as well as the viewing
window.
3. Check venting specifications are met. Long vent lengths, venting with
more than three elbows, blocked vent or combination venting may
cause this failure.
4. Check that flue gas limiter connector and spade connections are
secure.
5. Unplug heater and check the wiring harness connections on the
control board.
Exhaust temperature sensor -
happens if sensor is
disconnected or in short circuit
or appliance selection on “P7”
mode is not correct.
1. Check exhaust temperature sensor connection, see Fig. 2, [9].
2. Check sensor (< 100 ohm = short circuit).
3. Check “P7” mode: The correct selection is “Cd”.
Backflow temperature sensor
defect - happens if sensor is
disconnected or short circuit.
1. Check backflow temperature sensor connection, see Fig. 2, [13].
2. Replace exhaust temperature sensor.
Outlet temperature sensor fault
(Temperature below 0 °C or
above 98 °C).
1. Check red wire connections at hot water temperature sensor. Clean
terminals with an eraser. If badly corroded, replace sensor and wire
harness.
2. Sensor may trip if water temperature drops below 0 °C to protect
heater from freezing conditions. Any damage due to freezing conditions
is not covered under warranty.
3. Clean the water filter, any dirty in the faucets and also all the water
filters of the installation.
4. In areas where water has a high mineral content, periodic descaling
may necessary.
5. Check sensor.
Table 25
* By installer or service technician only.
