Bosch Therm 6000 S Installation And Operating Instructions Manual page 38

38 | Problem solving
Display Cause
Hot water temperature sensor
(NTC) at the exit of the
appliance detect a high
temperature of the hot water.
Temperature > 85°C
Cold water temperature sensor
fault.
Back ow temperature sensor
over 150 °C.
The appliance will close the
burner and lock (non-volatile).
Overheat sensor (ECO) open
circuit (resets when cooler
temperatures are detected
104 °C).
Table 21
* By installer or service technician only.
6 720 800 095 (2014/05)
Solution
1. Check the correct position and xation of the NTC sensor.
2. Check the electric connections and connectors of the hot water
temperature sensor. Clean terminals.
the sensor and cables. Check resistance (see Fig. 3, [2]).
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
may necessary.
1. Check connector on wires coming from top of watervalve for a secure
connection.
2. Sensor may trip if water temperature drops below 2 °C. Protect heater
from freezing conditions as any damage
covered under warranty.
3. Check sensor.
1. Check inlet/outlet vent pipes.
2. Check if secondary fan connections are disconnected.
3. Check if venting speci cations ar
with more than three elbows, blocked vent or combination venting may
cause this failure.
4. Call the Technical Assistance.
1. Disconnect power supply cord an
overheat sensor and the two connectors on the control board. see Fig. 2,
[7].
2. Check white wire connections at
with an eraser. If badly corroded, replace sensor and wire harness.
3. Check that venting speci cations
with more than three elbows, blocked vent or combination venting may
cause this failure.
4. Clean the water lter, any dirty in the faucets and also all the water
lters of the installation.
5. In areas where water has a high
may necessary.
6. Unplug power supply cord to th
for several minutes to allow cold wate
Close hot water tap and disconnect le
a multimeter, check continuity th
Replace sensor if open.
If the terminals are rusted, replace
mineral content, pe riodic descaling
due to freezing conditions is not
e met. Long vent lengths, venting
d check wire connections on the
the overheat sensor. Clean terminals
are met. Long vent lengths, venting
mineral content, pe riodic descaling
e water heater. Open a hot water tap
r to pass through heat exchanger.
ad wires to overheat sensor. Using
rough overheat sensor contacts.
Therm 6000S