Troubleshooting - Bosch GWH 345 ESR-N Manual

Troubleshooting

7 Troubleshooting
Fault Indication
E9
EA
F7
E0
F0
C4
C6
E2
A7
Table 18
34
Possible Cause
Shut down by the temperature limiter
(over 220°F temperature).
No Flame detected (no ignition).
"false flame" (error during self check of
electronic).
Shut down because of low voltage.
Internal error in the control unit.
Fan not working
Shut down by pressure switch.
Outlet temperature sensor defect (no
function)
Domestic hot water - Tank temperature
sensor defect (no function)
Check
• 1. Check position of outlet water
sensor. Ensure that sensor is firmly
attached to outlet pipe
• 2. Check temperature limiter, cables
and connections
• 3. Check system for air
• 4. Purge air from system if detected.
• 1. Check for flame, ignition
• 2. Check gas inlet pressure, gas
type, air inside gas pipe
• 3. Check manifold pressure for
proper operation of the gas valve
• 4. Check ionization sensor, cable
1)
• 5. Check control unit
•
6. Check ignition wires and connec-
tions.
• 1. Check for moisture on the
Electronics
• 2. Check cables, ionization sensor
contacts (corrosion)
• 3. Use diagnostic mode #12 to
verify if gas valve is closed
1)
• 4. Check control unit .
• 1. Check for adequate power supply
• 2. Check control unit for visible
1)
damage .
• 1. Check control unit connections
and wiring.
• .
2. Replace control unit
• 1. No power to fan, check for 120
volts at fan
• 2. Check wire connections
• 1. Blocked vent
• 2. Fresh air supply inadequate
• 3. Silicone tubes from pressure
switch to fan not connected or
reversed. Black (top) clear (bottom).
• 4. Check wire and connection.
• 1. Check sensor connection
• 2. Check cable (opened, short)
1)
• 3. Check control unit .
• 1. Check domestic hot water sensor
on tank for defects. Compare
parameter value of mode #6 to
actual tank water temperature
• 2. Check cable (opened, short)
1)
• 3. Check control unit .
.
6 720 607 909