Carrier 50FC Installation, Operation And Maintenance Instructions page 59

14 - MAINTENANCE
1) Inspection of electrodes
Dismantle the complete pilot fl ame and use a jet of compressed
air to clean the mesh and nozzle. Check the integrity of the
ceramic and use sandpaper to remove any oxidation on the
metal parts of the electrodes. Check the correct position of the
electrodes (see drawing below).
It is important that the detection electrode is at a tangent to the
head of the pilot and not inside it. The start-up electrode must
discharge onto the mesh of the pilot burner.
Verify that the start-up electrode
discharges on the external edge
of the pilot burner
2) Inspection of fl ue exhaust and air intake ducts
Visually inspect where possible or examine with specifi c tools
to learn the status of the ducts.
Remove dust that forms on the air intake terminal.
3) Inspection and cleaning of the venturi
Remove any dirt at the mouth of the venturi with a brush, and
be careful to not let it fall inside the venturi.
4) Inspection and cleaning of the exchanger and burner
Perfect combustion in PCH heaters prevents soot forming,
which is normally caused by bad combustion.
It is advisable, therefore, to not clean the exchanger and burner
unless there are exceptional circumstances.
An accumulation of soot inside the exchanger could be revealed
by a sizeable variation in the heat output that is not caused by
improper functioning of the gas valve.
Should it become required to clean the burner and/or
exchanger, all of the gaskets mounted between the burner and
the exchanger must be replaced.
5) Inspection and cleaning of the water trap
Clean the trap every year, and check the connections. Make
sure there are no traces of metallic residue. If metallic residue
has formed, increase the number of inspections.
6) Inspection of intake gas pressure
Verify that the intake pressure at the valve corresponds to the
value required for the type of gas connected.
This verification must be done with the heater on at the
maximum heat output.
7) Inspection of fl ame monitoring equipment
8) Inspection of the safety thermostat(s);
Keep the detection
electrode at a tangent
to the pilot burner
9) Inspection of the ionization current.
Replacing the gas valve of the burner
If the gas valve must be replaced, it is required to proceed with
an inspection and possibly calibrate the CO
adjustments on the Venturi pipe.
It is advisable not to calibrate the off set: the valve calibration is
performed by the manufacturer.
If necessary, carry out the combustion analysis procedure as
described in paragraph "Analysis of combustion".
It is recommended to always carry out the fl ue gas analysis after
replacing the gas valve.
With the heater operating, close the gas tap and verify that the
machine faults, signalled on the LCD display with code F10.
Reopen the gas tap, reset the fault and wait for the heater to
start back up.
This procedure must be done with the heater on and the
burner lit.
Open the thermostat series with an insulated tool [230 V],
remove the fast-on from the safety thermostat, wait for the F20
block signal to appear on the LCD display.
Reclose the thermostat series, then reset the fault.
This procedure can be done directly from the LCD display by
entering into the I/O menu (password 001). The IOn parameter
indicates the value of the ionization current, and the reading
is as follows:
- 100, indicates that the value is more than 2 microAmperes,
which is plenty for the equipment to function;
- from 0 to 100, indicates a value from 0 to 2 microAmperes;
for example, 35 corresponds to 0.7 microAmperes, which is
the minimum threshold detectable for the fl ame monitoring
equipment.
The value of the ionisation current must not be below 2 micro-
Amperes. Lower values indicate: the detection electrode in a
bad position, a rusted electrode or one about to stop functioning.
level through the
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