Bosch Therm 6000 S - Problem Solving; Problem;Cause;Solution

6 720 800 095 (2014/05) Therm 6000S
36 | Problem solving
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 ue gas limiter.
Temperature above 110 °C
inside the cabinet.
1. Check continuity of the ue gas limiter (normally closed).
2. Check for ue 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 specications are met. Long vent lengths, venting with
more than three elbows, blocked vent or combination venting may cause
this failure.
4. Check that ue gas limiter connector and spade connections are
secure.
5. Unplug heater and check the wiring harness connections on the
control board.
Resistance connections are not
correct.
1. Check resistance connection, see Fig. 2, [9].
Backow temperature sensor
defect - happens if sensor is
disconnected or short circuit.
1. Check backow 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 lter, any dirty in the faucets and also all the water
lters of the installation.
4. In areas where water has a high mineral content, periodic descaling
may necessary.
5. Check sensor.
Table 21
* By installer or service technician only.