Bosch GWH 345 ESR-L, Manual

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Troubleshooting
7 Troubleshooting
Fault Indication Possible Cause Check
E9 Shut down by the temperature limiter
(over 220°F temperature). • 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.
EA No Flame detected (no ignition). • 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
• 5. Check control unit
1)
•
6. Check ignition wires and connec-
tions.
F7 "false flame" (error during self check of
electronic). • 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
• 4. Check control unit
1)
.
E0 Shut down because of low voltage. • 1. Check for adequate power supply
• 2. Check control unit for visible
damage
1)
.
F0 Internal error in the control unit. • 1. Check control unit connections
and wiring.
•
2. Replace control unit
.
C4 Fan not working • 1. No power to fan, check for 120
volts at fan
• 2. Check wire connections
.
C6 Shut down by pressure switch. • 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.
E2 Outlet temperature sensor defect (no
function) • 1. Check sensor connection
• 2. Check cable (opened, short)
• 3. Check control unit
1)
.
A7 Domestic hot water - Tank temperature
sensor defect (no function) • 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)
• 3. Check control unit
1)
.
Table 18