Water Flow Switch; Fault Finding - Potterton Derwent Compact Plus Installation, Operation & Maintenance Manual

POTTERTON COMMERCIAL PRODUCTS DIVISION
INSTALLATION, OPERATION AND MAINTENANCE MANUAL
DERWENT COMPACT PLUS - CONDENSING

WATER FLOW SWITCH

For boilers fitted with a water flow switch, the installer
should check that it is not possible for the boiler to
flow when there is no water flow. This may be done by
checking the boiler closes down when the pumps are
switched off or the water flow is gated off. Always
restore the water
commissioning.

FAULT FINDING

Set out below are general guidance notes on system
fault finding.
Overheat Operation
Operation of the boiler overheat thermostat is
associated with a reduction in boiler water flow.
Where overheat operation is reported the following
should be checked.
a) The boiler/system pump has not tripped.
b) Pump overrun is operational to dissipate residual
heat from the boiler on system shut down.
c) System valves are open.
d) The boiler is operating at the correct rate and is
not overfired.
To reset the overheat thermostat allow the boiler to
cool down, remove the overheat thermostat knob and
press the reset button.
The use of a primary loop system is highly
recommended to provide a constant boiler flow rate
under all operating conditions.
Burner Lockout
The boilers have an integral safety system to allow the
safe and reliable operation of the burner. Failure of
the burner to operate correctly will cause the burner
control box to "lockout" and the lockout button on the
burner will illuminate to indicate this.
The lockout condition can be manually reset by
pushing the reset button and the control box should
restart its control sequence in an attempt to light the
flow before completing
burner. If the control box lockout will not reset or goes
to lockout after being reset then the services of a
boiler repair/maintenance company should be sought.
This service is available from Potterton Commercial
Division service offices at the addresses on the back
page of this manual.
WARNING: The lockout reset button should not be
repeatedly operated
situation may occur.
Should the boiler go to lockout, check the following
before attempting to relight the burner.
1 The gas meter pressure is above 18 mbar.
2 The electrical supply to the appliance is of the
correct voltage and polarity.
General Arrangement of Pilot Burner
7mm
Earth
18.5mm
SECTION 5
PAGE 21
otherwise a hazardous
Ignition
3-4 mm
Electrode
Ionisation
Electrode