25
221129A
1 1 C o m m i s s i o n i n g
2801
Diagram 11.5
DOMESTIC
HOT WATER
THROTTLE
11.6 Gas Rate Modulation - Honeywell
The minimum gas rate is factory preset and no
adjustment should be required.
ALWAYS CHECK HOT WATER BURNER
PRESSURE FIRST - REFER TO SECTION 11.5.
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 the minimum gas rate.
Check that the burner pressure is 2.5mbar +/-0.2mbar,
(1.0in wg +/-0.1in wg). If this is incorrect, it may be
adjusted by removing the cap and turning the larger
adjusting nut of the modulator, (anti-clockwise to
decrease the 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
16.1mbar, (6.5in 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 unattainable, check that the
gas supply is of adequate size, refer to Section 1.7 “Gas
Supply”. Put right as necessary.
Isolate the boiler from the electrical supply then
reconnect the modulator cable and refit the cap.
Isolate the boiler from the electrical supply then
reconnect the modulator cable and refit the cap.
11.6 Gas Rate Modulation - SIT
The minimum gas rate is factory preset and no
adjustment and should be required.
ALWAYS CHECK HOT WATER BURNER
PRESSURE FIRST - REFER TO SECTION 11.5.
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 it does not contact
any metallic parts.
Switch on the electrical supply.
Fully open a hot water draw off tap and the main burner
will light at the minimum gas rate.
Check that the burner pressure is 2.5mbar +/- 0.2mbar
(1.0in wg +/-0.1in wg). If this is incorrect, it may be
adjusted by turning the centre white adjuster screw of the
modulator, anti-clockwise to decrease, whilst at the same
time stopping the larger brass nut from turning, see
diagram 11.3.
Isolate the boiler from the electrical supply then
reconnect the modulator cable and refit the cap.
11.7 Domestic Water Flow Rate
Adjust the water throttle to obtain a flow rate of 9Litre/
min (2gall/min), (clockwise to increase), see diagram
11.5. This is equal to 7 seconds to fill a 1Litre container
(4seconds to fill a 1pint container). Close the tap when
adjustment is satisfactory.
The minimum water flow rate is 3.6Litre/min (0.8gall/
min) equivalent to 16.5 seconds to fill a 1Litre container
(9.5 seconds to fill a 1pint container). If this flow rate
cannot be achieved, check that there is no partial
blockage and that the supply is of adequate size.
Put right as necessary.
Close the hot water draw off tap.
11.8 Burner Pressure - Heating
