Fulton Hopkins (HPN) Horizontal Coil Thermal Fluid (hot oil) Heater - Manual (Page 41)

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SECTION 3
HPN-IOM-2014-0416
OPERATION
3-9
!
WARNING
All information in this manual is for
reference and guidance purposes,
and does not substitute for required
professional training, conduct,
and strict adherence to applicable
jurisdictional/professional codes and
regulations.
A qualifi ed installer, service agency
or the gas supplier must perform
installation and service on the fuel
delivery system.
During system boilout, it is imperative
that all system legs or paths are open
to ensure fl ow throughout the system.
Never open a cool or unheated user
leg of a system when the rest of the
system is above 210 F ( 99 C).
Do not attempt to start the
equipment for any testing prior
to fi lling and purging the vessel.
A dry fi re will seriously damage
the equipment and may result in
property damage or personnel injury
and is not covered by warranty. In
case of a dry fi ring event, shut off
the fuel supply and allow the vessel
to cool to room temperature before
fl uid is reintroduced to the pressure
vessel.
When opening any drains on the
equipment or piping system, steps
should be taken to avoid scalding/
burning of personnel due to hot
fl uids. Whenever possible, the system
should be cooled prior to opening any
drains.
Use only your hand to turn valve
handles. Never use tools. If the
handle will not turn by hand, don’t try
to repair. Forced or attempted repair
may result in fi re or explosion.
 Combustion
Before fi ring the heater familiarize yourself on the use of the controls, lighting,
and shutdown procedures.
 SEQUENCE OF OPERATION FOR GAS FIRED BURNERS
The burner is of forced design. The sequence of operation is as follows:
1. The fl ame programmer opens the main gas valve once stable pilot fl ame is
established.
2. Pressure regulators on both the pilot and main gas supply, supply pressure to
the proper level.
NOTE:  Note the maximum inlet pressure rating of each fuel train and supply a
step-down regulator if required. Consult the Fulton Companies if uncertain of the
maximum inlet pressure requirements.
3. Combustion air is delivered by a centrifugal blower fan. An air switch monitors
the pressure and is part of the fl ame programmer safety interlock circuit.
4. The fl ame programmer monitors the safe operation of the burner. Functions
include pre-purge of the combustion chamber, provision of ignition via the
ignition transformer and electrode, opening the pilot gas valve, monitoring
the pilot fl ame signal via the fl ame sensor, opening main gas valves and
providing post-purge of the combustion chamber.
5. The fl ame is monitored by a fl ame sensor. In the event of insuffi cient,
unstable, or non existent pilot or main fl ame, the fl ame sensor will cause a
safety lockout of the fl ame programmer. Safety lockout can also be caused if
the fl ame sensor is improperly positioned or grounded. After fault has been
corrected, reset by pressing the reset button on the casing of the burner
control box.
 MODULATING BURNER
The function of the fl ame programmer must be greatly extended in a modulated
system. Along with limit controls, operating controls and interlock devices, the
programmer automatically controls the operation of the burner, blower motor,
ignition, main fuel valves and modulating motor (or servo motors).
The sequence of operation is as follows:
1. Beginning with power on, limit switch closed, fuel valves closed, and
modulating limit controller closed and calling for heat, the fl ame
programmer begins its cycle and the blower motor starts prepurge.
The modulating circuit closes, driving the air dampers to maximum for
prepurge.
2. The air fl ow proving switch must be closed now. After timed prepurge,
the modulating motor (servo motor) drives the air damper to its low fi re
position. All start interlocks must be proven or the fl ame programmer will
lockout.
3. (Units with Gas Pilot) Ignition and pilot are energized and a timed trial for