Mechanical Operation Of - Power Flame C Series Installation & Operation Manual

3.

MECHANICAL OPERATION OF

FUEL/AIR CONTROL MODES
Figure 17
Typical Gas Burner with On-Off
Fuel/Air Control Mode (Model CR-G)
6
1
MECHANICAL OPERATION: This system uses a combina-
tion Diaphragm Gas Valve and Integral Pressure
Regulator (1) to control the on-off operation of gas to the
Blast Tube (2). A proven spark ignited gas pilot provides
ignition for the main flame. Gas flow control rate is
accomplished by adjustment of the main gas pressure
regulator and by a Limiting Orifice (a limiting orifice
is used when the gas flow rate - BTU input - through the
gas train components is higher than desired), located in
the Orifice Tee fitting (5) at the inlet to the gas manifold.
The Air Dampers (6) are adjusted and locked in place
with the Air Damper Arms (7) for a fixed firing rate. When
the gas pilot* has been proven by the flame detector*,
the Diaphragm Gas Valve will open slowly, allowing gas
to the Blast Tube. Blast Tube gas pressures are measured
Figure 18
Typical Gas Burner with Low-High-Off or Low-High-Low Fuel/Air Control Mode
(Model C-G)
1
5
12 10 11
MECHANICAL OPERATION: The Low-High-Off system
uses a Motorized Gas Valve (1) to control the Low-High-
Off operation of gas to the Blast Tube (2), as well as
8 5
8 7 3
4 14 13 16 15
7
2
at the 1 /
4
Orifice Tee. Refer to page 37, Table 10 for orifice sizing
information. See page 37, Figure 38 for side orifice detail.
*
Not shown in this depiction. See page 3, Figure 1.
Note 1
Component operational sequencing will vary with the specific
Flame Safeguard Control being used. Refer to the specific
Flame Safeguard Control bulletin supplied with the burner for
complete information.
Note 2
Optional On/Off systems may be supplied using a separate gas
pressure regulator and separate diaphragm or motorized gas
valve in place of the combination regulator/valve unit depicted.
Other components would remain as described.
2
movable Air Dampers (3) by means of the mechanical
Linkage (4). Gas flow control rate is accomplished by
adjustment of the Main Gas Pressure Regulator (5) and
by a Limiting Orifice (when installed) located in the Side
Orifice Tee fitting (7) at the inlet piping to the gas manifold.
A proven spark ignited gas pilot* provides ignition for the
main flame. When the gas pilot* has been proven by the
flame detector (scanner)*, the Motorized Gas Valve
begins to open, allowing a controlled fuel/air mixture to
the Blast Tube for low fire light off - and continues to open,
increasing the fuel/air flow until the high fire position has
been reached. Firing Head gas pressures are measured
at the 1 /
4
Tee. Refer to page 37, Table 10 for orifice sizing information.
The burner operates at high fire until the system load
demand is satisfied, at which time the Motorized Gas Valve
closes and the Air Dampers are returned to the light off
position in preparation for the next operating cycle. This
depiction shows the Linkage in the low fire start position.
The Low-High-Low system is identical to the Low-High-
Off system except that - the Motorized Gas Valve (1) has a
" Plugged Gauge Test Port (8) in the Side
" plugged Gauge Test Port (8) in the Side Orifice
C15
Rev.304