Fault Finding; Additional Checks - Potterton NXR3 Installation, Operation And Maintenance Manual

POTTERTON COMMERCIAL PRODUCTS DIVISION
INSTALLATION, OPERATION & MAINTENANCE MANUAL
NXR3
5. Following commissioning the boiler overheat and
control thermostats should be set to the required
operating setting.

Additional Checks

Where possible the system should be checked to
ensure that following purging of air there is no raw
water make-up. In particular, when the system is
operated in the hot condition, there should be no
discharge of water from the safety valve, open vent or
cold feed tank overflow that would otherwise lead to
unregulated raw water make-up when the system
cools down.

FAULT FINDING

General fault finding for burner failure should be in
accordance with the burner manufacturers handbook.
Set out below are general guidance notes on system
fault finding.
Overheat Operation
The boiler control panel has an inbuilt overheat
indicator lamp. 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 is adequate for the duty.
b) Operation of flow reducing devices, ie, TRVs,
compensated mixing valves, etc., do not reduce
the water flow rate through the boiler below the
minimum flow rate.
c) Pump overrun is incorporated to dissipate residual
heat from the boiler on system shut down.
d) The operation of
incorporate a time delay to allow for removal of
residual heat from the boiler.
e) The boiler is operating at the correct rate and is
not overfired.
The use of a primary loop system is highly
recommended to provide a constant boiler flow rate
under all operating conditions. For further information
please refer to the Potterton Technical Bulletin series.
Burner Lockout
The package burners supplied with the boiler unit
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
boiler back end valves
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
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 form 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. Fuel is available at the burner.
2. The electrical supply to the appliance is of the
correct voltage and polarity.
The boiler control boxes in some instances have
indicator dials as an aid to fault finding on boiler
lockout. In these instances refer to the control box
manufacturers data sheet for fault finding details.
SECTION 5
PAGE 25
otherwise a hazardous