Dunkirk 90-100, Installation, Operation & Maintenance Manual, Page: 6 / 56

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TABLE #1: SERIES 90 NATURAL GAS
SERIES 90-50
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 – – – – –
Manifold Pressure In W.C. 2.5 4 4 3.5 2.5 2.5
Orifice
43331094 43331094
SERIES 90-75
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 – – – – –
Manifold Pressure In W.C. 2.5 3.5 3.5 2.5 2.5 2.5
Orifice
43331092 43331092
SERIES 90-100
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 – – – – –
Manifold Pressure In W.C. 2.5 3.5 3.5 2.5 2.5 2.5
Orifice
43331090 43331090
++Contact local gas utility or distributor for Btu value of gas.
boilers for use aT HigH alTiTude
The boilers (with the exception of the 90-75 LP product) are factory
equipped for operation at altitudes ranging from 0-10,000 feet above
sea level. No changes to the factory settings are required for instal-
lations from 0-5,000 feet above sea level. For altitudes from 5,000-
10,000 feet above sea level the gas manifold pressure will need to be
adjusted based upon calorific (Btu) value of supply gas (contact local
gas utility or distributor for this value). For specific settings refer to
Table #1 for natural gas applications and
Table #2
for LP gas ap-
plications. Instructions on how to adjust the gas manifold pressure
settings are shown in
Figures 17 & 18
.
Note that 90-75 LP applications for 5,000 - 10,000 feet above sea
level will require an orifice change as well as a gas manifold pres-
sure adjustment based upon calorific (Btu) value of supply gas. Refer
to
Table #2
for altitude orifice kit part number. For replacing the
orifice refer to specific instructions included with the kit.