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2.0 Burner Operation and Controls
WARNING
Turndown Method
Control Motor Requirements
Piloting
Flame Monitoring
Main Gas Valve Train
Limit Controls
Blower Shut-Off
Failure to use suitable flame sensing devices and automatic fuel shut-off
valves can cause explosions and fires. The owner/user and/or his insur-
ance underwriter is responsible for providing, using, and maintaining
suitable limit controls, flame supervision, and other safety devices for this
burner, and for properly interfacing all electrical equipment and sequenc-
ing burner operation.
Ratiomatic burners are designed to operate with either two-position or modulating
temperature control systems. Gas-air ratio control is performed by a ratio regulator
as shown in Figure 2.
Stroke: 90°. For applications with unusually high backpressures or drafts, motor
travel may need to be restricted to less than 90°. Eclipse recommends adjustable
stroke motors or motors with travel-limiting auxiliary switches for these jobs.
Timing: 15 seconds minimum.
Mounting: Can be mounted on either side of the burner. However, if an air inlet filter
is used, the control motor must be mounted on the side opposite the filter.
A spark ignited pilot is an integral part of each burner. An adjustment cock is included
for pilot adjustment.
The customer must provide a pilot gas valve train that includes a pilot gas regulator
and a solenoid valve.
If combustion chamber pressure is likely to be more than ± 1"w.c. (2.5 mbars) or if
it is expected to fluctuate during operation, cross-connect the pilot regulator vent to
the chamber.
50 thru 600 sizes: A flame rod is included with the burner; UV scanners and mount-
ing kits are available as options.
750 thru 2500 sizes: UV scanner only; must be ordered separately.
Gas should be supplied to the burner inlet through a valve train which complies with
NFPA Standards and all applicable local codes.
When multiple burners are fed from the same valve train, a check valve must be in-
stalled in the gas line as close as possible to the proportionator inlet to prevent un-
even flows at low fire. Main regulator pressure may need to be increased to com-
pensate for the check valve pressure drop.
CAUTION: Customer supplied main gas regulators for inlet pressures greater
than 1 psig (70 mbars) for 50-200 Ratiomatics or 5 psig (350 mbars) for 300-
2500 Ratiomatics must be capable of tight shut-off to prevent leakage and sub-
sequent proportionator damage.
Limit controls and safety equipment should comply with current NFPA Standard 86
and all applicable local codes and/or standards. NFPA Standards are available from:
National Fire Protection Association
Batterymarch Park
Quincy, Massachusetts 02269
During shutdown, the blower must not be turned off until the chamber temperature
has dropped below 250° F (121° C). This is to prevent hot gases from flowing back
through the burner and blower and damaging them.
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