System Gassing Troubleshooting - Bosch Condens GC4700iW 15 S User Instructions

Malfunction or failure
10.4

System gassing troubleshooting

WARNING
Caution must be exercised when venting radiators or adjusting
system pressure after commissioning of your boiler.
Do not repeatedly vent your radiators, if symptoms persist, contact a
heating engineer.
▶ Do not vent air from radiators whilst the central heating is switched
on; turn your boiler off.
▶ Whilst venting radiators, do not allow the pressure on the boiler to
drop below the pressure at which it is normally set.
Does system pressure increase when the boiler is on?

NO

Is your system pressure regularly
dropping (i.e. you constantly have to
top up your boilers pressure)
 
NO YES
 
Contact a service
The boiler is fine
engineer
Table 12 System gassing flow chart
14
Is your system pressure constantly increasing even when the boiler is off for extended periods of time?

NO


YES

Does system pressure increase to
the high pressure red zone on the
pressure gauge/display?

NO

The boiler is fine
CAUTION
If the pressure in your heating system is repeatedly rising (this can
be checked via the boilers pressure gauge or digital display and
should be checked when the system is cold), and especially if you
need to keep venting the radiators, urgent action is required and you
must contact a heating engineer. This can indicate that there is
corrosion occurring within the heating system
Note: Ensure the reading stays between minimum and maximum
operating pressures at all times whilst the boiler is operating
▶ This must be properly addressed to prevent serious damage to the
entire system.
▶ Failure to properly maintain the heating system may affect your
warranty.
Can you confirm that the filling link is not stuck open/
Does the problem
persist?

YES

The boiler is fine
Contact a service
engineer

YES

passing water in any way?

YES

Contact a service
 
YES

NO

Condens 4700iW – 6721864485 (2023/04)

NO

engineer