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ThermJet, V2, Technical Information, Edition 2.14
Step 4: Flame Monitoring System
A flame monitoring system consists of two main parts:
• A flame sensor
• Flame monitoring control
Flame Sensor
There are two types that you can use for a ThermJet
burner:
• UV scanner
• Flame rod
A UV scanner can be used with all combustor types.
The UV scanner must be compatible to the flame
monitoring control that is used. Refer to the manual of
your selected control for proper selection of the scanner.
NOTE:
Flame rod option is not available for the TJ300 and
larger.
• The standard flame rod is used with natural gas,
propane, butane and pre-heated air up to 300ºF.
You can find more information in Info Guide 832.
Flame Monitoring Control
The flame monitoring control is the equipment that
processes the signal from the flame rod or the UV
scanner.
For flame monitoring control you may select several
options:
• Flame monitoring control for each burner: if one
burner goes down, only that burner will be shut off
• Multiple-burner flame monitoring control: if one
burner goes down, all burners will be shut off
Eclipse recommends the following:
• Trilogy series T600; see Instruction Manual 835
• Bi-flame series; see instruction manual 826
• Multi-flame series 6000; see Instruction Manual 820
• Veri-flame; see Instruction Manual 818
If other controls are considered, contact Eclipse to
determine how burner performance may be affected.
Flame monitoring controls that have lower sensitivity
flame detecting circuits may limit burner turndown and
change the requirements for ignition. Flame monitoring
controls that stop the spark as soon as a signal is detected
may prevent establishment of flame, particularly when
using UV scanners. The flame monitoring control must
maintain the spark for a fixed time interval that is long
enough for ignition.
DO NOT USE the following:
• Flame monitoring relays which interrupt the trial for
ignition when the flame is detected
• Flame sensors which supply a weak signal
• Flame monitoring relays with low sensitivity
■
A UV scanner can possibly detect another
burner’s flame if it is in the line of sight, and falsely
indicate flame presence. Use a flame rod in this
situation. This helps prevent accumulation of
unburned fuel which, in extreme situations, could
cause a fire or an explosion.
Step 5: Combustion Air System (Blower &
Air Pressure Switch)
Effects of Atmospheric Conditions
The blower data is based on the International Standard
Atmosphere (ISA) at Mean Sea Level (MSL), which
means that it is valid for:
• Sea level
• 29.92" Hg (1,013 mbar)
• 70ºF (21ºC)
The makeup of the air is different above sea level or in a
hot area. The density of the air decreases, and as a result,
the outlet pressure and the flow of the blower decrease.
An accurate description of these effects is in the Eclipse
Combustion Engineering Guide (EFE 825). The Guide
contains tables to calculate the effect of pressure, altitude
and temperature on air.
Blower
The rating of the blower must match the system
requirements. You can find all the blower data in: Bulletin/
Info Guide 610.
Follow these steps:
1. Calculate the outlet pressure.
When calculating the outlet pressure of the blower,
the total of these pressures must be calculated.
• The static air pressure required at the burner
• The total pressure drop in the piping
• The total of the pressure drops across the valves
• The pressure in the chamber (suction or
pressurized)
• Recommend a minimum safety margin of 10%
WARNING
