Use and Care Manual

14
6-583.12
INSTALLATION - HIGH ALTITUDE ACCESSORY KIT
If the heating value of the gas being supplied is different than
the values shown in Tables 13.1 and 13.2, use the following
equation to determine the appropriate manifold pressure for the
altitude and gas heating value being supplied.
Equation 14.1 - Manifold Pressure for Derated Gas
WHERE:
MP
ACT
= Manifold Pressure (in. W.C.) at Altitude –
Manifold pressure setting for the heater being
installed
BTU
TBL
= BTU/ft
3
Content of Gas –
Obtained from Tables 13.1 or 13.2 (whichever is
applicable)
BTU
ACT
= BTU/ft
3
Content of Gas –
Obtained from the local utility company
MP
SL
= Manifold Pressure (in. W.C.), at Sea Level –
Use 3.5" W.C. for natural gas and 10.0" W.C. for
propane gas
NOTE: Only the primary manifold pressure should be adjusted
on units equipped with two-stage or modulating gas controls.
No adjustments to the low fire manifold pressure are necessary
on these units.