P-K MACH
®
Gas Fired Boiler
Technical Service 1.877.728.5351
Revised: January 3, 2020
Released: January 3, 2020
Patterson-Kelley 2020
All Rights Reserved.
1004905981 P-K MACH C1500H-C4000 Installation and
Owners Manual (Rev F Jan-2020).docx
Page 115
Appendix B
– Boiler Altitude Derate Schedule
For installations over 2,000 ft. elevation, a derate schedule is applied.
The appliance’s input rating must
be reduced by
4% per 1,000 ft. which is illustrated in the graph below:
Although the appliance’s capacity is reduced due to the lower air density, the combustion tuning should
follow the standard combustion guidelines of Section
. Tune the combustion for the same O
2
and
CO
2
levels as discussed in Section