Specifications

– 21 –
With the gas input pressure established, the flue
gas analysis can now be preformed. This is
checked in the stand off box where the induced
draft fan airflow switch tube is located.
The following readings should be taken but not limited
to:
CO
2
% Net Stack Temperature
O
2
% Combustion Efficiency
CO %
If necessary, make adjustments on burner air shutter.
DO NOT change the fuel input rate.
The following list covers general combustion problems
and some of the possible cures. Conditions may vary in
the field. Refer to combustion chart for efficiency.
CAUTION: Check local codes for maximum
allowable percentages and amounts of emissions.
Low Carbon Dioxide (CO
2
)
• Fuel input too low
• Excess burner air
• Wrong draft setting
Detectable Carbon Monoxide (CO)
• Fuel input too high
• Not enough burner air
• Restricted draft
• Flame impingement
Excessive Stack Temperature
• Draft setting too high
• Excess burner air
• Fuel input too high
Low Oxygen (O
2
)
• Oxygen reading must always be a positive
percentage
Cycle burner several times to ensure smooth light off
and proper operation. Visually observe the flame pat-
tern. There must be no flame impingement or hot spots
on the combustion chamber that could cause scaling.
Check voltage and amperage on all motors.
Check all dampers, linkages, and locking quadrants to
make sure they are secure and operating correctly.
Flame Safeguard – Close the last manual gas valve
before burner. Operate unit in heat mode. After pilot
flame has been established, close manual pilot gas
valve. The flame safeguard must trip out within 15 sec-
onds.
Gas Pressure Switches – The low gas pressure switch
will trip out and must be reset before resuming opera-
tion when the inlet gas shut off valve is turned off, or
inlet gas pressure is lower than the trip point. The high
gas pressure switch can be checked by reducing the
setting of its trip point lower than the burner operating
pressure. The switch should trip out and shut off the
burner. Return the adjustment to its original setting and
reset to resume operation.
Temperature Controls – The temperature controls are
checked by adjusting control to a higher temperature to
allow burner to cycle on. Adjust control to a lower tem-
perature to allow burner to cycle off. Return the control
to its original setting.
Air Pressure Switches – The air pressure switches
can be checked by turning the adjusting screw to call for
a higher pressure than is normally used on the system.
Recycle is automatic when the switch is returned to its
original setting. If the burner or draft proving switches
open, this could cause the flame safeguard to go into
lockout mode.
Limit Controls – The limit controls are checked by
adjusting control to a lower temperature setting while
the unit is operating on high fire and observe cut-off.
Return the control to its original setting. Manual reset
may be required on some controls.
Make sure all the safety and controls
are working properly.
FINAL CHECKS AND ADJUSTMENTS
SAFETY AND CONTROLS CHECKOUT