Install Instructions

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 Specifi cations
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 speci ed 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 CO 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 con rmed 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.  e 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.