Bosch C 1210 ES Installation Manual page 51

Display Cause
Primary fan rotation too low in
operation.
No rotational speed sensor signal
from primary fan.
(Flashing) Water flow signal over specified
maximum value.
Water flow > 10 gallon/min.
(Status message).
Over-temperature
outlet temperature sensor.
Temperature > 203°F
Cold water temperature sensor
fault.
Table 29
6 720 644 887
Solution
1. Reset errors, disconnect power supply cord and check wire
connection on back side of fan and the connectors on the control
board, see
2. Check supply voltage. It must be 120VAC and properly
grounded.
3. Check that venting meets installation specifications. Long vent
lengths, venting with more than three elbows, blocked vent or
combination venting may cause this failure.
4. Ensure intake and exhaust terminations maintain the required
minimum clearances. Cross contamination between intake and
exhaust may cause the fan to alter its rotational speed.
5. Check gas pressure. Low gas pressure may cause the fan to
change its speed to meet desired temperature.
6. Possible defective control unit call Bosch Water Heating for
further instructions.
1. Reset errors, disconnect power supply cord and check wire
connections on back side of primary fan and the two connectors
on the control board, see
2. Check supply voltage. The heater must be connected to
120VAC on a properly grounded dedicated outlet.
3. Possible defective component in fan or defective control unit
call Bosch Water Heating for further instructions.
1. Disconnect power supply cord and check wire connections on
water valve and the two connectors on the control board, see
84 page 66
,
2. Excessive water pressure and flow. Ensure water pressure is
less than 150psi and flow rate is below 10 gallons per minute.
detected by 1. Check that the outlet sensor is firmly attached to the vertical
section of the hot water pipe, see
2. Check red wire connections at hot water temperature sensor.
Clean terminals with an eraser. If badly corroded, replace sensor
and wire harness.
3. In areas where water has a high mineral content, periodic
descaling may be necessary. See chapter
directions.
4. Check sensor (ref.
1. Check connector on wires coming from top of watervalve for a
secure connection. See
2. Sensor may trip if water temperature drops below 36°F (2
Protect heater from freezing conditions as any damage due to
freezing conditions is not covered under warranty.
3. Measure sensor resistance (ref.
Fig. 84 page 66
, .
Fig. 84 page 66
,
.
Fig. 83
page 54, chapter 9).
Fig. 77 page 58
,
page 55, chapter 10).
Error codes
.
Fig.
page 65
, .
6.3 page 41
, for
.
°
C).
51