for specific adjustment details (pages 15 and 17).
Gas On/Off System with Oil Reduced Air, Low Fire Start
RALFS See page 18.
Gas Low/High/Off System with Oil Low/High/Off System
For Gas - movable air dampers are adjusted to provide a
smooth light off position and then moved to the high fire
position through mechanical linkage from a motorized gas
valve. The air dampers are adjusted to open to provide
maximum combustion efficiency at the gas high fire input rate.
For oil - the same air dampers are operated by a hydraulic
oil cylinder which, through mechanical linkage, is adjusted
to provide a smooth light off and then open to a point where
the highest combustion efficiencies will be achieved at the
high fire input rate. Smooth oil light off is further achieved
by the use of a solenoid oil valve bypass system, which
allows a reduced amount of oil to flow at light off and then
switches to the high fire rate (simultaneously energizing the
hydraulic oil cylinder) once low fire has been established.
The mechanical linkage from the gas valve is physically
arranged so that the hydraulic oil cylinder (which is non-
operational when burning gas) has no effect on the gas
linkage adjustments. Similarly, the gas valve (which is non
operational when burning oil) has no effect on oil linkage
adjustments. It should be noted that when the hydraulic oil
cylinder moves the air dampers, the movement of the air
dampers will cause the motorized gas valve linkage to move
up and down with the opening and closing of the hydraulic
oil cylinder. The motorized gas valve linkage is free floating,
and even though it moves with the oil cylinder operation, it
cannot cause any gas flow to pass through the motorized
gas valve. Refer to the mechanical operation of the Gas
Low-High-Off system and the Oil Low-High-Off system for
specific adjustment details (pages 15, 19 and 20).
Note
The oil side operation can be supplied with either a Suntec or a
Webster oil pump. Refer to the mechanical operation for the specific
system for adjustment details.
Gas Low/High/Low System with Oil Low/High/Low
System
Refer to the above explanation of Gas Low/High/Off System
and Oil Low/High/Off System. The Gas Low/High/Low
Systems are identical in operation, except that an additional
temperature or pressure control is added to the system, which
at a selected preset point will electrically switch the motorized
gas valve (which is a different model number than the
Low/High/Off motorized gas valve) to an adjustable Low
Fire position. This low fire position is an adjustment that is
designed internal to the gas valve and, depending upon
the specific manufacturer of the valve, will be found either
in the valve wiring compartment or under a removable cap
on top of the valve. Refer to the valve manufacturer’s
product bulletin supplied with the burner for specific details.
For the Low/High/Low system oil side operation, the
additional temperature or pressure control will also cause
the solenoid oil valves, hydraulic oil cylinder and air
dampers to go to a low fire position at the same preset
temperature or pressure as the gas side operation. The
oil side low fire position is one and the same position as
the light off position, i.e., the air dampers and oil pressures
have identical settings (as compared to the gas side -which
can be adjusted, if desired, to have different settings for
light off and low fire). Refer to the mechanical operation
of the Gas Low-High-Low system and the straight Oil
Low-High-Low system for specific adjustment details
(pages 15, 19 and 20).
Note
The oil side operation can be supplied with either a Suntec or a
Webster oil pump. Refer to the mechanical operation for the
specific system for adjustment details.
Gas Full Modulation System with Oil Full Modulation
System
The Gas system uses an automatic diaphragm or
motorized gas shutoff valve to control the on/off flow of
the gas. The Oil system employs an oil solenoid valve to
control the on/off flow of oil to the oil nozzle. A modulating
motor controls the modulated positioning of a butterfly
type Gas Proportioning Valve while a V ported metering
oil valve provides the modulating function in the oil nozzle
return line. The modulating motor also controls the
positioning of the combustion air dampers, through
appropriate sequencing - providing low fuel/air input for
a smooth low fire start and an infinite number of fuel/air
positions between full low and high fire. Additional finite
fuel/air adjustments are provided when the optional Power
Flame Varicam
TM
characterized fuel metering system is
used (optional).
When firing Gas the oil metering valve will open and close
because it is linked to the modulating motor; however, the
oil solenoid shutoff valve remains closed, and no oil is
allowed to flow to the nozzle. Similarly, when firing Oil, the
butterfly gas valve will open and close because it is linked
to the modulating motor; however, the main automatic
gas supply shutoff valve (motorized or diaphragm type)
remains closed, so no gas is allowed to flow to the
burner head.
Refer to the mechanical operation of the Gas Full
Modulation system and the Oil Full Modulation system
(pages 16 and 21, as well as page 22 entitled Gas/Oil -
Linkage Adjustment Full Modulation - Standard System) for
specific adjustment detail. If supplied, also refer to page 22,
covering Detail and Adjustments on Modulating Varicam
TM
Characterized Fuel Metering System.
Burner Start Up and Service Test Equipment Required
The following test equipment is required to ensure
proper start-up and adjustment of burner equipment to
For Any Fuel
CO
2
indicator or O
2
analyzer
Stack thermometer
Draft gauge or inclined
manometer
Combination volt/ammeter
D.C. microammeter or D.C.
voltmeter, as required by Flame
Safeguard programmer selection
For Gas
CO indicator
U-Tube manometer or cali-
brated 0-10" and 0-35" W.C.
pressure gauges
(Higher pressure ranges may
be necessary depending upon
gas inlet supply pressure.)
For Oil
Compound vacuum/pressure
gauge - 0-30" vacuum/0-30 PSIG
0-400# oil pressure gauge (two
required for internal bypass type
oil nozzles)
Smoke tester
obtain maximum efficiency and reliability of operation.
See page 41 for CO
2
/O
2
/ Excess Air Curves.
C24
Rev.304
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