Detroit Radiant Products Company FA Series - Manual (Page 38)

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FA Series
High Altitude Operation
The FA Series heater is factory configured for altitudes from 0 – 2,000 ft above sea level. If the
unit heater is being installed at an elevation above 2,000 ft, the input rate will have to be de-rated
to ensure proper operation. The deration is achieved by a gas orifice change.
The installation of the high altitude orifices must be done prior to putting the heater in operation
and prior to connecting the gas supply line. The manifold pressure may need to be re-adjusted
after orifices are installed. Refer to Charts 3.5 through 3.7 for proper high altitude conversion kit.
For altitudes above 9,500 feet, consult factory.
High Altitude Conversion Kit Installation:
1 Remove service access door by unscrewing the 5/16” (#10) sheet metal screws securing the door.
2 Disconnect all wires connecting to the gas control valve.
3 Remove the manifold pipe from the burner assembly by removing the four mounting screws.
4 Slide the manifold pipe assembly out of the control compartment.
5 Remove gas orifices from the manifold using a 7/16” wrench.
6 Thread in the new orifices of the correct kit, starting threads by hand. Take care not to cross thread
the orifices (See C harts 3.5 through 3.7 for proper kit number and orifice size).
7 Tighten gas orifices to a torque of 150 inch pounds. No thread sealant is necessary, as the brass is
designed to seal to the steel manifold pipe at the proper torque.
8 Inspect all the newly installed orifices to ensure they are straight and aligned 90° to the manifold
pipe. Correct or replace any misaligned orifices.
9 Reinstall the manifold pipe assembly to the unit, ensuring that each orifice is properly aligned with
the burners. Secure with four 5/16” (#10) screws.
10 Reconnect all wires to the gas control valve.
11 Proceed with the installation of the gas supply line as described within this manual.
Chart 3.5 • High Altitude Conversion Kits for Elevations of 2,000 to 4,500 Feet
WARNING
!
Explosion hazard. This heater must be converted by a trained gas installation and
service personnel only. Failure to comply could result in personal injury, asphyxiation,
death, and fire or property damage.
Model
Number of
Orifices
Kit Number Orifice Size
Natural Gas Propane Natural Gas Propane
FA-100 4 HKN-43_4 HKP-55_4 43 DMS 55 DMS
FA-125 5 HKN-43_5 HKP-55_5 43 DMS 55 DMS
FA-150 6 HKN-43_6 HKP-55_6 43 DMS 55 DMS
FA-175 7 HKN-43_7 HKP-55_7 43 DMS 55 DMS
FA-200 7 HKN-41_7 HKP-54_7 41 DMS 54 DMS
FA-225 9 HKN-43_9 HKP-55_9 43 DMS 55 DMS
FA-250 9 HKN-42_9 HKP-54_9 42 DMS 54 DMS
3.0 Installation • High Altitude Operation