Bosch SSB1000 TL - Appendix H - De-Rating for Altitude Installation

6720866942 (2018/06) US SSB
56 | DE-RATING FOR ALTITUDE INSTALLATION
Appendix H - De-rating for altitude installation
When the appliance is installed at an altitude higher than 2000 ft, the fan speed must be set to the top of the available range in any case and a de-rating
of the input capacity must be considered in function of the altitude combined with the total length of the vent and combustion air pipe as reported in the
following table (input BTU/hr):
SSB 800 SA
Altitude (ft) From 0% to 25% From 25% to 50% From 50% to 75% From 75% to 100%
0-2000 798000 798000 798000 798000
3000 732482 719768 707056 694344
4000 708185 695893 683603 671312
5000 683889 672021 660151 648281
6000 659592 648144 636698 625250
7000 635298 624272 613246 602220
8000 611001 600397 589793 579187
9000 586707 576523 566341 556159
10000 562408 552648 542888 533126
SSB 1000 SA / 1000 TL
Altitude (ft) From 0% to 25% From 25% to 50% From 50% to 75% From 75% to 100%
0-2000 1000000 1000000 1000000 1000000
3000 917896 901967 886035 870105
4000 887450 872047 856645 841243
5000 857004 842131 827256 812383
6000 826557 812212 797866 783520
7000 796112 782296 768478 754661
8000 765665 752376 739087 725800
9000 735220 722461 709701 696939
10000 704773 692541 680310 668078
To calculate the de-rating of the input capacity follow this example:
We have an SSB 1000 SA boiler installed at 5400 ft with a 6” ue system. The equivalent length of the vent pipe installed is 55 ft.
The equivalent length of the air combustion pipe installed is 35 ft.
The total equivalent length of the ue system is 55+35 = 90 ft. The maximum equivalent length for this type of installation is (see IOM manual) 100 ft.
The % range is 90/100 = 90%. This value is within the 75% and 100%.
Now the correct de-rating value is given from the value of the fourth column (From 75% to 100%) of the SSB 1000 SA / 1000 TL table that crosses
the row with 6000 ft: 783520 BTU/hr.