GB-7
D
GB
F
NL
I
E
▷
As not all the effects caused by the equipment
are known, setting the burner using the pressure
values is only approximate. It is possible to set
the burner precisely by measuring the flow rates
or flue gas.
Restrictors
▷
The air volume required for the low-fire rate at a
given air pressure is determined by the ignition
position of a butterfly valve, a bypass hole in the
air valve or an external bypass with restrictor.
Hot-air compensation
▷
The combustion air pressure
p
Air
must be in-
creased in hot-air operating mode (lambda =
constant).
0
100
200
300
400
100
150
200
250
T
Air
[°C]
p
Ai
r
[%]
▷
The gas pressure is increased by 5 – 10 mbar.
▷
The total burner capacity
P
B
rises as the air tem-
perature
T
Air
increases.
0
100
200
300
400
100
110
120
T
Air
[°C]
P
B
[%]
Setting the air pressure for low fire and high
fire
Shut off the gas and air supply.
▷
Air measuring nipple
L
, external dia. = 9 mm (0.35").
p
atm.
p
air
0
3
5
2
4
L
Loosen the
screw 2
turns.
Fully open
the air supply.
p
atm.
p
air
0
3
5
2
4
L
Low fire:
▷
The burner must only be ignited at low fire (be-
tween 10 and 30% of the rated capacity Q
max
–
see type label).
•
Reduce the air supply on the air control valve
and set the desired low-fire rate, e.g. using a
limit switch or mechanical stop.
▷
On air control valves with bypass, the bypass
orifice should be determined on the basis of the
required flow rate and the existing supply pres-
sure if required.
High fire:
•
Set the required air pressure p
air
on the air restric-
tor upstream of the burner.
•
When using air restricting orifices: check the air
pressure p
air
.
Preparing the gas pressure measurement for
low fire and high fire
•
Connect all measuring devices for subsequent
fine adjustment of the burner.
▷
Leave the gas supply closed.
▷
Gas measuring nipple
G
, external dia. = 9 mm
(0.35").
•
Read off the gas pressure p
gas
for the required
flow rate from the enclosed flow rate curve for
cold air.
[mbar ("WC)]
[m
3
/h (ft
3
/h)]
p
gas
p
air
p
air
p
gas
Q
air
Q
gas
p
atm
=
atmospheric
pressure.
