Supplied By www.heating spares.co Tel. 0161 620 6677
23
221473B
11 Commissioning
5048
Diagram 11.1
5044
SWITCH 'ON'
SWITCH 'OFF'
SMALL
ADJUSTMENT
NUT (MAX.
PRESSURE)
SCREW
5052
Diagram 11.2
TEST
POINT
LARGE
ADJUSTING
NUT (MIN.
PRESSURE)
SPINDLE
CAP
ELECTRICAL
CONNECTOR
(GREY)
PRESSURE
GAUGE 'A'
CENTRAL HEATING
SELECTOR SWITCH 'C'
NEON
RESET
BUTTON
This flow rate should prevent any modulation of the gas pressure.
Check the burner pressure is /-0.35bar (+/-0.14in wg)
of 15.5mbar (6.2in wg), the hot water burner pressure. If this is
incorrect, the burner pressure may be adjusted to the correct
setting by turning the hot water gas pressure adjuster
(potentiometer), using an insulated screwdriver, see diagram
11.3. Gain access to the adjusters on the control board by
removing the control housing cover, see diagram 11.3. Turn the
adjuster slowly, always making adjustment by reducing below
the required pressure then increasing up to the required setting
(turn clockwise to increase).
Close the hot water draw off.
If the maximum pressure cannot be obtained, check that the gas
supply is of adequate size, refer to Section 1.7.
11.5 Gas Rate Modulation
The minimum gas rate is factory preset and no adjustment
should be required.
ALWAYS CHECK HOT WATER BURNER PRESSURE FIRST
- REFER TO SECTION 11.4.
To check the minimum gas rate, first make sure that the boiler
is isolated from the electrical supply at the external isolator.
Disconnect one of the electrical connectors (grey), from the
modulator, see diagram 11.3. Insulate the connector to make
sure that it does not contact any metallic part of the boiler.
Switch on the electrical supply.
Fully open a hot water draw off tap and the main burner will light
at minimum gas rate.
Check that the burner pressure is 1.8mbar +/-0.2mbar (0.7in wg
+/-0.1in wg). If this is incorrect, it may be adjusted by removing
the cap and turn the larger adjusting nut of the modulator,
(anticlockwise to decrease pressure).
If the above adjustment was necessary, it will be essential to
check that the maximum pressure can still be obtained. Push
the spindle gently in to the stop and hold it in. The maximum
pressure should not be less than 16.0mbar (6.4in wg). If this
pressure cannot be achieved, obtain it by turning the small
adjusting nut (clockwise to increase the pressure). Always
adjust the minimum pressure first.
If the maximum pressure is unobtainable, check that the gas
supply is of adequate size, refer to Section 1.7. Put right as
necessary.
Isolate the boiler from the electrical supply then reconnect the
modulator cable and refit the cap.
11.6 Domestic Water Flow Rate
Adjust the water throttle to obtain a flow rate of 12Litre a minute
(2.6gall/min), clockwise to increase, see diagram 11.4. This is
equal to 5.0 seconds to fill a 1Litre container, 2.8 seconds to fill
a 1pint container.
Close the tap when adjustment is satisfactory.
The minimum water flow rate for operation of the boiler is
3.6Litre a minute, (0.8gall/min), equal to 16.5 seconds to fill a
1Litre container, 9.5 seconds for 1pint. If this flow rate cannot
be achieved, check that there is no blockage and that the supply
pressure is adequate.
Refer to Table 2.
Close the hot water draw off tap.