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14.0 Fault Finding
Domestic Hot Water -
Follow operational sequence
Primary flow switch
operated
Fan runs at max speed.
Pump runs
Turn preheat control to on.
Preheating function starts
after 25 seconds.
neon flashing.
Primary water is diverted
from preheating circuit to
DHW heat exchanger.
neon illuminated
Air pressure switch proved.
neon flashing
Spark at ignition electrode
for up to 10 seconds.
neon flashing
Go to section ‘B’
neon flashing
Go to section ‘C’
neons flashing
Go to section ‘D’
neon flashing
Go to section ‘I’
Turn the selector to reset.
If regular resetting is
required or appliance still
does not operate
investigation is necessary.
neon flashing
Go to section ‘E’
YES
YES
YES
NO
Turn On/Off/Reset selector
to position.
neon illuminated.
Primary water diverted to
DHW preheating circuit.
Open DHW tap fully. DHW
flow switch operated.
Burner lights.
Burner output modulates to
maintain temperature set at
preheat control.
Burner goes out.
Burner extinguishes after
10 seconds.
NO
Close DHW tap.
DHW flow valve senses no
flow. DHW flow switch
released off.
Preheating function
restarts.
neon flashing
Go to section ‘A’.
Go to section ‘M’.
External controls and
where fitted, integral timer
calling for heat.
Go to section ‘L’.
Ensure controls are set to
demand and verify the
contacts are closed.
DHW flow rate more than
2.5 l/min.
Is mains water filter and
differential assembly
clean?
DHW flow valve diaphragm
damaged.
Replace diaphragm.
DHW flow valve rod
obstructed.
Continuity across DHW flow
microswitch terminals and
PCB - A5 connector
terminals 5 & 6
Replace DHW flow
microswitch.
Replace main PCB
Go to section ‘J’.
Turn selector to the reset
position. If the neon does
not extinguish go to
sections H and K.
Change main PCB.
Go to section ‘F’.
Reduce the DHW flow rate.
If burner does not modulate
clean DHW temperature
sensor and DHW heat
exchanger. If modulation
does not occur go to
section ‘G’.
External controls and where
fitted, integral timer calling
for heat.
Fan stops.
Pump continues to
run for 30 seconds.
Operation
sequence correct
Ensure controls are set to
demand and verify the
controls are closed.
Go to section ‘L’.
YES
NO
NO
YES
NO
NO
YES
YES
YES
YES
YES
NO
NO
YES
YES
NO
NO
YES
YES
NO
YES
NO
NO
YES
NO
NO
YES
YES
NO
NO
YES
YES
YES
NO
YES
YES
YES
YES
YES
neon flashing
NO
YES
NO
Summary of Contents for Performa 28i
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