Ratings
7
NOTICE
Knight XL Boiler
AHRI Rating
Model Number
Note: Change “N” to
“L” for L.P. gas models.
Input
MBH
(Note 2)
Min Max
Gross
Output
MBH
(Note 1)
Net
AHRI
Ratings
Water,
MBH
(Note 2)
KBX0400(N,L)
39.9
399
387
337
KBX0500(N,L)
50
500
485
422
KBX0650(N,L)
65
650
631
549
KBX0800(N,L)
80
800
776
675
KBX1000(N,L)
99.9
999
969
843
KBX0400-O(N,L)
39.9
399
384
334
KBX0500-O(N,L)
50
500
482
419
KBX0650-O(N,L)
65
650
626
544
KBX0800-O(N,L)
80
800
770
670
KBX1000-O(N,L)
99.9
999
962
837
Other Specifications
Boiler
Water
Content
Gallons
Water
Connections
Gas
Connections
Air
Size
Vent
Size
(Note 3)
4.4
2"
1"
4"
4"
4.9
2"
1"
4"
4"
6.2
2"
1-1/4"
4"
6"
7.3
2"
1-1/4"
4"
6"
8.8
2-1/2"
1-1/4"
6"
6"
4.4
2
"
1
"
4
"
4
"
4.9
2
"
1
"
4
"
4
"
6.2
2
"
1-1/4
"
4
"
6
"
7.3
2
"
1-1/4
"
4
"
6
"
8.8
2-1/2
"
1-1/4
"
6
"
6
"
Installation & Operation Manual
Notes:
1. Knight XL boilers require special gas venting Use only
the vent materials and methods specified in the Knight XL
Installation & Operation Manual.
2. For US installations above 2,000 feet elevation, reference
NFPA 54 for de-rate information.
De-rate values are based on proper combustion calibration
and CO2 adjusted to the recommended levels.
3. For Canadian installations above 2,000 feet elevation,
follow all applicable local codes and regulations.
4. Ratings have been confirmed by the Hydronics Section of
AHRI.
5. Knight XL boilers comply with the requirements of CSD-1
Section CW-400 requirements as a temperature operation
control. The manual reset high limit provided with the
Knight XL is listed to UL353 or UL60730-2-9.
Maximum allowed working pressure is located on the rating plate.
