© MHG Heating Ltd
MHG Heating Ltd, Unit 4 Epsom Downs Metro Centre, Waterfield, Tadworth, Surrey, KT20 5LR
P:0845 6448802 F:0845 6448803 E:
W: www.mhgheating.co.uk
010617
60
To indicate that the module is operating under the control of the
Chimney Sweep
Button the display (3) will indicate 100 for High Fire and 0 for Low Fire and the red
Lockout LED (7) will flash with a double pulse.
To alternate the module between High Fire and Low Fire the
Chimney Sweep and
P Buttons must be pressed for less than 1 second.
P Button
High Fire
Button
Low Fire
This mode is maintained until the limit thermostat temperature is reached or the
Chimney Sweep or P Button is pressed from more than 1 second. The module
stops operating when the button is released.
Whilst the module is operating under the control of the Chimney Sweep Button (with
adjustment) the gas valve can be adjusted to give correct flue gas analysis readings.
Each module is equipped with a modulating gas valve.
The modulating gas valve must be set at High Fire and Low Fire to ensure correct
operation throughout its modulating range.
It is advisable to check the combustion figures on High and Low Fire prior to carrying
out any adjustments.
Adjusting the High Fire has a marked effect on the Low Fire figures.
Whereas adjusting the Low Fire has little effect on the High Fire figures.
The High fire adjustment is carried out via the 2.5mm Allen Key socket D
The High Fire adjustment is a Gate type restrictor.
Therefore turning the screw clockwise will close the gate and thus restrict the
quantity of gas passing through to the burner.
The Low fire adjustment is carried out via the 2.5mm Allen Key socket N
The Low Fire adjustment is a diaphragm governor.
Therefore turning the screw clockwise will increase the pressure on the diaphragm
and thus increase the quantity of gas passing
through to the burner.
Legend
A.
Valve Inlet Gas Pressure Test Point
B.
Valve Outlet Gas Pressure Test Point
D.
High Fire Adjuster (Gate Type)
