MGN 2800N HP 9
B
URNER
A
IR
C
ONTROLS
The air for combustion is controlled by an adjustable air flap located inside the air inlet on the right
hand side of the burner viewed from the rear. Its purpose is to regulate and control the volume of
combustion air flowing through the burner. Combustion air is controlled by a three position servo
motor. Positions for high and low flame air are adjustable. A fully closed position is incorporated for
when the appliance temperature/pressure is satisfied.
Air Diffuser
The air diffuser is fitted to the front end of the inner assembly and located within the flame tube.
Its function is to control the volume of combustion air and create a pressure drop over the burner
head to ensure good fuel/air mixing and flame stability.
Air Pressure Switch
The air pressure switch is located on the right side of the burner casing viewed from the rear. It is
required to prove adequate air flow throughout the burner operating cycle. Air flow failure at any
stage will result in burner lockout.
B
URNER
G
AS
C
ONTROLS
Gas Nozzle
The gas nozzle is fitted to the front end of the inner assembly and located in the flame tube. The
holes in the gas nozzle are designed to suit the output of the particular burner model and gas type
being used.
High Gas Pressure Switch
A high gas pressure switch is fitted and pre-wired to the gas train to ensure that if the gas pressure at
the burner head increases above the gas pressure at maximum continuous running, then the burner
will shut down to a safe condition, thus indicating a fault on the governing valve (air/gas ratio valve).
The switch is factory set to the maximum position.
Final adjustment of this switch is described in the
Commissioning
section on page 20.
Low Gas Pressure Switch
The low gas pressure switch is located on the inlet side of the gas valve block on the left of
the burner, viewed from the rear. It is required to monitor inlet gas pressure during the
burner operating cycle. Gas pressure failure will result in safe shutdown of the burner. Final
adjustment of this switch is described in the
Commissioning
section on page
20.
Gas Valve Train
The gas valve train system includes an air/gas ratio controller, safety shut-off valve, and gas
regulator in the start rate line. Three impulse pipes are connected to the air/gas ratio
controller. All are factory supplied. One pipe is connected to the burner hinged extension
and supplies combustion air pressure to the ratio controller. A second pipe is connected
downstream of the valve set and supplies gas pressure to the ratio controller. The third pipe
is vented to atmosphere. Valve adjustments are detailed in
Valve Adjustment Diagram
on
page 13.
ELECTRICAL
DATA
3 Phase 400V 50Hz
Burner
Model
Motor
(kW / rpm)
Start
Current (A)
Full Load
Current (A)
Main Fuse
(A)
Cable Size
(mm
2
)
MGN 2800N HP
7.5 /2800
57
15.2
40
4.0
