9
ThermJet, V2, Technical Information, Edition 2.14
Modulating Gas with Fixed-Air Control
(Figure 3.2)
A burner system with modulating control gives an input
that is in proportion with the demands of the process. ANY
input between high and low fire is possible.
1. Air:
The amount of air to the burner is fixed.
2. Gas:
The control valve
is in the gas line. It can modulate
to any position between low and high fire.
NOTE:
Use of a ratio regulator
in a fixed-air system is
optional on a single burner system only. However,
eliminating the ratio regulator will adversely affect the
ignition reliability at inputs greater than 40% of maximum.
Figure 3.2 Modulating Gas with Fixed-Air Control
Optional IF flame monitoring system controls the main gas shut-off
valve train AND ignition above 40% of maximum is NOT required.
NC
Automatic
shut-off by
zone
NC
Automatic
shut-off at
the burner
P
to other
Zones
to other Burners
Main gas
shut-off
valve train
to other Burners
to other
Zones
P
to other
Zones
to other
Zones
Main gas
shut-off
valve train
to other Burners
to other Burners
P
NC
Main gas
shut-off
valve train
(optional)
Multiple Burners
Automatic Shut-Off
at the Burner
Multiple Burners
Automatic Shut-Off
by Zone
Single Burner
