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Step 7:
Set Low Fire Gas
Step 8:
Verify the Gas
Settings
f
a
s
ixeD
ir
ystem
Step 1:
Reset the System
Step 2:
Set High Fire Air
18
1.
Drive the system to low fire.
2.
Use the gas curve from the appropriate ExtensoJet datasheet
for the gas being used to determine the differential gas
pressure required for low fire. This is your target value for low
fire.
3.
Measure the gas pressure at the first burner.
4.
Adjust the ratio regulator until the gas flow is on the target
value. (Refer to Bulletin 742 for adjustment.)
Note:
It is very difficult to measure the very low pressures
experienced at low fire, and it may be necessary to rely
on visual inspection. This is especially true when gas
turndowns in excess of 10 to 1 are being used. The main
intent is to provide a clean stable flame with a good flame
signal that will not cause the furnace temperature to
overshoot.
If the pressure required is too low to be measured, then
adjust the ratio regulator until a gas flow is obtained that
will provide a clean stable flame with a strong flame
signal.
Make sure that all settings are still the same after cycling the
system several times between high and low fire.
Note:
When all the settings have been completed, mark the
position of the indicator on the butterfly valves to indicate
valve position.
When you adjust a fixed-air system for the first time, you must
follow these steps:
1.
Reset the system
2.
Set high fire air
3.
Ignite the burners
4.
Set high fire gas
5.
Set low fire gas
6.
Verify the gas settings
1.
Close the automatic gas valves and the gas cocks.
2.
Fully open the manual air butterfly valve at each burner.
a.
Drive the automatic zone air control valve to high fire.
b.
Adjust the automatic zone air control valve so that it is fully
open. The automatic zone air control valve can be either a
butterfly valve or a CRS valve.
3.
Set the manual gas butterfly valve at each burner to 50%
open.
4.
Start the blower.
Note:
Make sure that the blower rotates in the correct direction.
If incorrect, then have a qualified electrician rewire the
blower to reverse its rotation.
1.
Set the system to high fire, but
2.
Use the air curves in "Orifice Curves" from the appropriate
ExtensoJet datasheet to find the differential air pressure
needed at high fire. This is now the target value for high fire.
3.
Set high fire air.
Eclipse ExtensoJet v2 Installation Guide No. 230, 9/17/2008
DO NOT ignite the burner(s).
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Troubleshooting
