© MHG Heating Ltd
93
MHG Heating Ltd Unit 4 Epsom Downs Metro Centre, Waterfield, Tadworth, Surrey KT20 5LR
Telephone 08456 448802 Fax 08456 448803 Email
Web www.mhgheating.co.uk
010711
The output of the appliance can be altered by using the
buttons to move between 100%
maximum outout and 0% minimum output.
Alterantaivley the output of the appliance can be altered by using the
buttons to descrease or
increase the output by 1% per press.
This mode is maintained until the limit thermostat temperature is reached or the coommissioning
buttons are pressed from more than 1 second.
Whilst the appliance is operating under the control of the commissioning mode (with adjustment) the
gas valve can be adjusted to give correct flue gas analysis readings.
The appliance 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. Where as 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)
N.
Low Fire Adjuster (Governor Type)
A flue gas analyser must be used to ensure that the correct combustion setting are achieved.
This is undertaken by inserting the analyser’s probe in to plugged hole within the flue collector of the
appliance or in the tapping in the flue immediately above the appliance if present.
