Dunkirk Q90-100 Series IV User Manual
Page 2
2
See
Tables #1 and #2 for specifi c high altitude orifi ce information.
Gas Conversion Procedure
When changing from Natural to Propane or vice
versa, use correct conversion orifi ce for boiler
model.
1.
Turn off manual gas valve.
2.
Remove front door. Use 5/16” nut driver to
remove top panel.
3.
Use 9/64” Allen wrench to remove adapter
block from gas valve. Take care not to lose
o-ring under the block. See Figure #3.
4.
Use adjustable or 1¼” wrench on bushing
to remove gas orifi ce assembly from mixer
turning counter clockwise. Do not use
channel locks, pipe wrench, etc, as damage
to bushing may occur. See Figure #2.
5.
Use small pipe wrench to remove orifi ce
from bushing by turning counter clockwise.
Install correct orifi ce for boiler being
converted. Apply small amount of pipe dope
to threads of orifi ce leaving last two threads
clean. Turn clockwise into bushing.
TABLE #1: NATURAL GAS
MODELS 050 MBH
Stock Factory
Btu Value of Natural Gas++
Settings
750
850
950
1000
1050
Altitude in Ft.
0-5,000
5,000-10,000
Normal Input (MBH)
50
–
–
–
–
–
Combustion Setting (CO
2
)
8.7 - 9.7% (CO
< 100 ppm)
Gas Orifi ce
43331094
Burner Plate
109006405
MODELS 075 MBH
Stock Factory
Btu Value of Natural Gas++
Settings
750
850
950
1000
1050
Altitude in Ft.
0-5,000
5,000-10,000
Normal Input (MBH)
75
–
–
–
–
–
Combustion Setting (CO
2
)
8.7 - 9.7% (CO
< 100 ppm)
Gas Orifi ce
43331092
Burner Plate
109006406
MODELS 100 MBH
Stock Factory
Btu Value of Natural Gas++
Settings
750
850
950
1000
1050
Altitude in Ft.
0-5,000
5,000-10,000
Normal Input (MBH)
100
–
–
–
–
–
Combustion Setting (CO
2
)
8.7 - 9.7% (CO
< 100 ppm)
Gas Orifi ce
43331090
Burner Plate
109009105
++Contact local gas utility or distributor for Btu value of gas.
PRESSURE
REFERENCE PRESSURE
4-WAY CONNECTOR
PRESSURE REGULATOR
ADJUSTMENT
(UNDER COVER SCREW)
GAS VALVE VENT
OUTLET PRESSURE TAP
(1/8" PLUG)
DIFFERENTIAL
PRESSURE
GAUGE
TO PRESSURE SWITCH
WHITE TRANSPARENT
VINYL TUBING
U-TUBE
MANOMETER
BUSHING
MIXER
ON
OFF
C
HIGH ALTITUDE RATINGS FOR NATURAL GAS
Figure 2 - Gas Assembly and Inlet Air Assembly