CleaverBrooks FLX Operation, Service And Parts Manual page 15

Profire V Burner
meet load demands. The low fire positions bypass oil back to
the storage tank. At high fire, the metering valve is in the
closed position. The modulating motor positions the metering
valve and the air damper simultaneously.
IGNITION SYSTEM
Oil only models VL-13 to 55 are supplied with direct spark
ignition. Models VL-60 to 168 are supplied with a gas pilot
system. Gas and combination gas-oil models are supplied
with a gas ignition system. The standard pilot gas train
consists of a manual shutoff cock, a gas pressure regulator,
and a solenoid operated gas shutoff valve.
GAS HANDLING SYSTEM
Depending upon the requirements of the regulating authority,
the gas control system and gas train may consist of some, or
all, of the following items:
1. GAS VOLUME VALVE
The butterfly type valve is positioned by linkage from the
modulating motor and control the rate of flow of gas.
2. MAIN GAS VALVES
Electrically operated safety shutoff valve(s) that open to
admit gas to the burner. Standard U.L. burners include:
• Models 13-25: Diaphragm gas valve & solenoid valve.
• Models 30-50: One motorized gas valve w/proof of clo-
sure or two safety shutoff valves.
• Models 55-120: One motorized gas valve w/proof of
closure and one safety shutoff valve.
• Models 126-168: Two motorized gas valves.
(Two motorized gas valves can be optionally provided on all
models.)
3. MAIN GAS REGULATOR
Regulates gas train pressure to specified pressure required at
the burner manifold. Input is set by main gas pressure
regulator adjustment.
4. MAIN GAS COCKS
Used for manual shutoff of the gas supply upstream of the
pressure regulator. A second shutoff cock downstream of the
main gas valve(s) provides a means of testing for leakage
through the gas valve(s).
HIGH GAS PRESSURE SWITCH (Models 30-168)
5.
A pressure actuated switch that remains closed when gas
pressure is below a selected setting. Should the pressure rise
above the setting, the switch contacts will open causing main
gas valve(s) to close. This switch requires manual reset after
being tripped.
LOW GAS PRESSURE SWITCH (Models 30-168)
6.
750-177
A pressure actuated switch that remains closed when gas
pressure is above a selected setting. Should the pressure drop
below this setting, the switch contacts will open, causing
main gas valve(s) to close. This switch requires manual reset
after being tripped.
A
OPERATION: Metered gas flows through the main gas
shutoff cock, through the pressure regulators to the automatic
gas valves and butterfly valve to the gas manifold. The
butterfly gas valve modulates flow to burner input demand.
The butterfly valve is positioned through mechanical linkage
by the modulating motor. The air control damper is
positioned simultaneously by the modulating motor. The
automatic gas valve(s) cannot be energized unless the
combustion air proving switch is closed. The low and high
gas pressure switches must be closed to prove proper gas
pressure.
A normally open vent valve, if required, is located between
the two automatic gas valves. This valve is shut when the
automatic gas valves are open. When the automatic valves are
closed, the vent valve is open for venting gas to the outside,
should any be present.
Notice:
Gas train components upstream of the
butterfly valve are shipped loose to be mounted by
the installer.
Notice:
Pilot gas supply connection must be
upstream of the main gas pressure regulator.
Chapter 2
B
2-3