Bosch Therm 8000 S GWHC 27 CTDE Installation And Operating Instructions Manual page 42

42 | Problem solving
Display Cause
(Flashing) Outlet temperature sensor not
sensing expected output
temperature. (Status message,
not an error)
Primary fan rotation too low in
operation.
No rotational speed sensor
signal from primary fan.
(Flashing) Water ow signal over
speci ed maximum value.
Water ow > 37 l/min.
Software/hardware failure.
Table 25
* By installer or service technician only.
6 720 680 174 (2012/09)
Solution
1. Check that the sensor is rmly at
hot water pipe.
2. Ensure that hot water sensor is not placed on any bends in the hot
water pipe or misreading may occur.
3. Check gas pressure. Low gas pre ssure may prevent the heater from
reaching desired output temperature.
4. Check supply voltage.
5. Possible defective control unit
1. Disconnect power supply cord an
side of fan and the two connectors on the control board.
2. Check supply voltage.
3. Check venting speci cations are me
more than three elbows, blocked vent or combination venting may
cause this failure.
4. Ensure intake and exhaust term
clearances stated in the manual. Cross contamination between intake
and exhaust may cause the fan to
5. Check gas pressure. Low gas pre ssure may cause the fan to change
its speed to meet desired temperature.
6. Possible defective control unit
1. Disconnect power supply cord an
side of fan and the two connectors on the control board.
2. Check supply voltage.
3. Possible defective component in f
Technical Assistance.
1. Disconnect power supply cord an
valve and the two connectors on the control board.
2. Excessive water pressure and ow
than 10 bar and ow rate is below 37 Litros
1. Disconnect power supply cord an
connections on control board as well as ground connection on heater
chassis.
2. Pressing the wrong combination of
create confusion among the microprocessors inside. In this case, the
error code should not happen more
water heater. Turn water heater back on and try resetting error code.
Use the reset button ( ) to reset any error codes.
3. Possible defective control unit
tached to the vertical section of the
, call the Technical Assistance.
d check wire connections on back
t. Long vent lengths, venting with
inations maintain the required
alter its rotational speed.
, call the Technical Assistance.
d check wire connections on back
an or defective control unit, call the
d check wire connections on water
. Ensure water pressure is less
per minute.
d check the two wire and ground
buttons on the control unit can
than once or twice. Turn o the
, call the Technical Assistance.
Therm 8000 S