22
221873B
6989
Diagram 10.1
7811
BURNER PRESSURE
TEST POINT
GAS CONTROL
VALVE
Diagram 10.2
CLOCK-TIMER
COVER
CONTROL BOARD
COVER
SECURING
SCREW (4)
BURNER PRESSURE
ADJUSTING TOOL
DOMESTIC HOT
WATER BURNER
PRESSURE
POTENTIOMETER
HEATING
BURNER PRESSURE
POTENTIOMETER
PLASTIC
PLUGS
Please ensure the “Benchmark” logbook is completed and left
with the user.
10.1 Filling Domestic Water Circuit
Check that the boiler is isolated from the electrical supply, at the
external isolator.
Fully open the domestic water supply stop cock or valve in the
supply to the boiler.
Open the inlet domestic water isolation valve, lever in line with
the valve body, see diagram 6.1.
Open all hot water draw-off taps and close them when water
flows. Check for water soundness of the whole domestic water
system and boiler.
10.2 Filling the Heating System
Open the two central heating isolating valves, levers in line with
the valve body, see diagram 6.1.
Flush, fill and vent the system refer to Section 4.8 “Filling
Sealed Systems”.
WARNING. SEVERAL COMPONENTS OPERATE ON MAINS
VOLTAGE AND WITH THE OUTER CASE REMOVED, LIVE
COMPONENTS BECOME EXPOSED.
Make sure that the automatic air vent is operating correctly.
Take care not to splash any of the electrical components.
Open the controls cover.
Refer to diagram 3 Instructions for Use. Operate button “J”
between “L” summer and “K” winter to ensure that water flows
through all parts of the boiler and air is not trapped in the boiler
internal bypass.
10 Commissioning
Pressurise the system until the pressure is 1.5bar. Check the
heating system and boiler for water soundness.
Check the operation of the safety valve by turning the safety
valve knob in the direction of the arrow.
Lower the pressure to the initial cold fill design pressure, refer
to Table 1. Position the set pointer on the boiler pressure gauge
at this pressure also.
Refit inner case front.
10.3 Preparation for Lighting
Isolate the boiler from the mains electrical supply at the external
isolator.
Purge gas supply test for soundness . Turn on the gas service
cock, slot in line with the length of the cock.
Loosen the burner pressure test point screw and connect a
suitable pressure gauge, see diagram 10.1.
10.4 Burner Pressure - Hot Water
Connect the electrical supply; the pump will operate for about 30
seconds, then the pump will stop.
Fully open the largest hot water draw off tap whereby the main
burner will light, the flames gradually increasing to the maximum.
Check the soundness of the boiler gas joints, with the main
burner on, using a leak detection fluid. Take care not to splash
any of the electrical components.
To achieve this flow rate a water pressure of at least 0.8bar is
required during commissioning, although subsequently the
appliance will work at a minimum pressure of 0.5bar.
This flow rate should prevent any modulation of the gas pressure.
The burner pressure is factory preset and no adjustment should
be required.
Check the burner pressure is /-0.2mbar. of 14.3mbar. If
this is incorrect, the burner pressure may be adjusted to the
correct setting by turning the hot water gas pressure adjuster
(potentiometer), located on the control board. To gain access
remove the two screws securing the controls facia, see diagram
9.1.
Hinge the control facia forward.
Remove the plastic plugs. Using the burner adjusting tool
supplied. (clockwise to increase), see diagram 10.2. Turn the
adjuster slowly, always making adjustment by reducing below
the required pressure then increasing up to the required setting.
Close the hot water draw off.
CABLE ENTRY
COVER
SECURING SCREW (2)
Slacken do not remove
CONNECTION
IGNITION
RATE
SETTING
POTTENTIOMETER
SENSING
LEAD
IGNITION
LEAD (2)
CHASSIS
EARTH LEAD
