DORCHESTER DR-FC 120, Installation, Comissioning And Maintenance Instructions

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Instruction manual DR-FC 75
F03 (lock out error)
The pressure switch
fails to work correctly
Damaged wiring/Open
circuit
1. Check the wiring between the pressure switch and the
controller
2. If necessary, replace the wiring
If the error cannot be resolved or is persistent, contact your
installation engineer
To replace the necessary parts, you must contact your installation
engineer
Pressure switch not
closing
1. Check the fan speed (12.5 "Display the selected water heater")
2. Check that the hoses on the pressure switch and the air supply
hose between fan and burner are correctly fitted. Refit them if
necessary
3. Check for cracks in the hoses on the pressure switch and in the
air supply hose between fan and burner. If necessary, replace
the hoses.
4. Check whether the chimney flue is compliant (3.9 "Air supply
and chimney flue discharge") .
5. Check for blockage in the chimney flue. Remove any blockage
that may be present
6. Check for blockage in the condensation water discharge.
Remove any blockage that may be present.
7. Measure the pressure differential across the pressure switch.
See the table (12.5 "Display the selected water heater") . If there
is insufficient pressure differential, clean the heat exchanger. If
the pressure differential is acceptable, check that the pressure
switch is closing, using a multimeter.
Code + description Cause Measure Remark