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If the pressure is 150mm (6ins) water gauge or more the filter must be replaced.
Removing the Oxygen Probe from the Flue
WARNING: Before attempting to remove the probe, switch off the system and the boiler. It
is essential to switch the burner off since dangerous levels of carbon monoxide may be pres-
ent in the flue.
Since the body of the probe will be hot, it will be necessary to use heat resistant gloves to
hold the probe.
Do not operate the boiler without the probe or blanking plate fitted since dangerous levels
of carbon monoxide may be present in the flue.
The Fireye Oxygen Probe Type NX2012 is retained in the flue by six 6mm stainless steel socket
head cap screws.
•
Loosen the 3 screws securing the probe end cap and slide the cap down the flexible conduit.
Take care, since the end cap may be hot.
•
Access is now available to the electrical terminations. Remove the plug from the printed circuit
board allowing the flexible conduit fitting to slide out of the probe body complete with the plug.
Since the body of the probe will be hot, it will be necessary to use heat resistant gloves to hold
the probe.
•
Remove the six retaining screws. The probe can be extracted from the flue taking care not to
damage the sealing gasket.
•
The only customer replaceable items are the flue thermocouple and oxygen filter.
•
If it is necessary to operate the boiler while the probe is removed, the blanking plate supplied
with the equipment must be fitted to the probe flange.
•
Refitting is the reverse of the removal procedure. Ensure that the screws are tightened sequen-
tially.
Filter Replacement
•
Remove the oxygen probe from the flue as detailed in section 6.4.3, and unscrew the insulating
flue thermocouple mounting blocks from the snout.
•
Before removing the three 6mm stainless steel nuts and spring washers which retain the snout, it
is important to hold the body horizontal or snout down to prevent soot or other deposits from
falling into the probe body.
•
When the 3 nuts and washers have been removed, the snout can be drawn off the mounting studs
to allow the captive filter assembly to be removed.
Calibration air pump.
350cc/min
150mm (6ins)
max
