Verify The Burner Firing Rate; Estimating Rate - Beckett CG10-24 Manual

Verify the Burner Firing Rate

The primary method for verifying the burner's firing
rate is to assure that the burner is operating with the
correct manifold pressure and the correct setup for
either natural gas or propane.
1. Turn off electrical power to the burner and close the
main shutoff cock supplying gas to the burner.
2. Remove the plug from the outlet pressure tap on
the burner manifold end of the gas valve and install
a hose barb fitting and manometer.
3. Turn on system power and gas supply and initiate a
call for heat to light the burner.
4. Verify the valves regulating pressure. Let the burner
continue to run and adjust the gas valve pressure
regulator in the following steps to obtain the correct
manifold pressure.
5. Manifold Pressure is to be used to set the burners
firing rate. See Table 8 on page 25.
6. Remove the regulator cover screw from the
regulator adjustment tower and turn the regulator
adjust screw clockwise to increase pressure or
counterclockwise to decrease pressure. Set the
regulator to produce the correct water column
reading in the manometer. Check the appliance
breech or draft setting and adjust if necessary as
it can affect the setting. Replace the regulator
cover screw.
7 . Turn off the burner and turn off all electrical power
to the system.
8. Remove the manometer hose and barb fitting from
the gas valve outlet pressure tap.
9. Replace the outlet pressure tap plug and tighten
(clockwise 40 – 60 in.-lbs.).
10. Turn on system power and start the burner.
11. Check for leaks at the gas valve outlet pressure tap
plug using a leak detection solution or soapsuds.
Bubbles forming indicate a leak. SHUT OFF GAS
AND FIX ALL LEAKS IMMEDIATELY.
Burner Manual — CG10-24
If the burner is firing natural gas it may be possible to
verify the firing rate by "clocking" the gas meter:
1. Locate the gas meter and examine its display to
be sure that you can determine a 1 cubic foot
usage of gas and that the meter is temperature
compensated.
2. Contact the gas utility to find the heating value
of the gas. It can vary from about 950 BTU/Ft
about 1,100 BTU/Ft
3
3. Examine the gas piping to know of any other gas
appliances connected to it. Turn them off so that
only this burner is using gas from the meter.
4. Start the burner and use a stopwatch to measure
the number of timed seconds it takes for the
burner to fire 1 cubic foot of gas.
5. Calculate the firing rate in BTU/Hr. using the
following equation:
Firing rate BTU/Hr. = Heating value (BTU/Ft
3,600 ÷ Timed seconds
For example, if the heating value is 1,050 BTU/Ft
and you timed 1 cubic foot of gas at 42 seconds
then firing rate BTU/Hr = 1050 x 3,600 ÷ 42 which
calculates to 90,000 BTU/Hr.
If the burner is firing LP gas, a meter is
usually not available. Contact your LP supplier
for recommendations.

Estimating Rate

Manifold to Furnace Pressure information can be used to
estimate the burner's firing rate when it is not possible
to clock a meter for the rate.
To estimate the burner's firing rate:
Measure the furnace pressure over fire.
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Measure the manifold pressure (at the manifold
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pressure test connection).
Subtract the furnace pressure from the manifold
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pressure.
Compare the result to the data in Figure 19
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and Figure 20 on page 26 as appropriate for
your burner.
Section: BURNER START-UP
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