Step 5: Combustion Air System: Blower And Air Pressure Switch - Eclipse ThermJet TJ0015 Design Manual

Step 5:
Combustion Air Sys-
tem: Blower and
air pressure switch
Series SMJ turbo blower
Effects of atmospheric conditions
The blower data is based on the International Standard Atmo-
sphere (ISA) at Mean Sea Level (MSL), which means that it is
valid for:
• Sea level
• 29.92" Hg (1,013 mbar)
• 70ºF (21ºC)
The makeup of the air is different. above sea level or in a hot
area. The density of the air decreases, and as a result, the outlet
pressure and the flow of the blower decrease. An accurate de-
scription of these effects is in the Eclipse Combustion Engineer-
ing Guide (EFE 825). The Guide contains tables to calculate the
effect of pressure, altitude and temperature on air.
Blower
The rating of the blower must match the system requirements.
You can find all the blower data in: Bulletin/Info Guide 610
Follow these steps:
1. Calculate the outlet pressure.
When calculating the outlet pressure of the blower, the total of
these pressures must be calculated.
• The static air pressure required at the burner
• The total pressure drop in the piping
• The total of the pressure drops across the valves
• The pressure in the chamber (suction or pressurized)
• Recommend a minimum safety margin of 10%
Eclipse ThermJet Design Guide No. 205, 3/5/07
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