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Technical Specifications/Logs
Is your system pressure constantly increasing even
when the boiler is off for extended periods of time?
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
Does your PRV
The
regularly drip?
boiler
is
fine
NO
Check
Check/
the CH
replace
system for
PRV
leaks
Fig. 192 System gassing flow chart
106
NO
YES
Does system pressure increase
above 2.5bar or enter the high
pressure red zone (Max
operating pressure)
on the pressure gauge/display?
NO
The
boiler
higher than expected?
is
fine
YES
NO
Is the Expansion
Vessel pre-charge
too low?
NO
Check
Expansion
Vessel is sized
correctly for
the system
YES
Have you confirmed that the
filling link is not stuck
open/passing water in any way?
Confirm the filling link is
closed and check that the
YES
Is the Expansion
Vessel pre-charged
YES
Do the radiators
regularly vented?
YES
Corrosion
Re-
is probably
pressurise
occurring within the
the EV
heating system which
is causing system
gassing.
The system should
be cleaned
and treated to
comply with
BS 7593
PRV = Pressure Relief Valve
EV = Expansion Vessel
NO
YES
Plate Heat Exchanger
is not cross leaking
Plate heat
exchanger
leaking?
NO
have to be
YES
NO
Most
likely a
cross-leaking
component in
the boiler.
Further
investigation
required
Greenstar 1000 – 6721835943 (2023/08)
YES
Does the
problem
persist?
NO
The
boiler
is
fine
YES
Replace
Plate Heat
Exchanger
0010036323-001
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