11
ThermJet, V2, Technical Information, Edition 2.14
High/Low Gas with Fixed-Air Control
(Can also be used for pulse firing.)
A burner system with high/low control gives a high or a low
input to the process. NO input between high and low fire
is possible.
1. Air:
The amount of air to the burner is fixed.
2. Gas:
a. Low fire: A control input closes the solenoid valve
. Low fire gas passes through the butterfly valve
.
b. High fire: A control input opens the solenoid valve
. High fire gas passes through the open solenoid
valve
.
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 3.4 High/Low Gas with Fixed-Air Control
NC
Automatic
shut-off by
zone
NC
Automatic
shut-off at
the burner
to other Burners
to other Burners
to other
Zones
to other
Zones
Main gas
shut-off
valve train
P
P
P
to other
Zones
to other
Zones
Main gas
shut-off
valve train
to other Burners
to other Burners
Main gas
shut-off
valve train
(optional)
Multiple Burners
Automatic Shut-Off at the Burner
Multiple Burners
Automatic Shut-Off by Zone
Single Burner
