2-1/2 M.P.T. Supply Connection
9-3/8”
Centerline Of Burner Plate
36” 29-1/2” 20”
17”
4”
2-1/2 F.P.T. Return Connection
3/4”
L8”
33”
A
pprox. 14”

OWB-35 and OWB-50 Specifications

1-1/2” Supply Connection
Circulato
r
26” 21-1/2”
15-1/2”
12-1/4”
1-1/2”
Return
Connection
L
25”
A
pprox. 14”

OWB-9, OWB-15, and OWB-25 Specifications

Boiler
Model Burner
GPH Input
BTU’s
Output
Capacity
BTU’s
NET
Rating
Water
BTU/HR.
NET
Rating
Water
SQ.FT.
Approx.
Dry
Weight
Lbs.
Vent
Connect
Dia.
Inches
Dim
“L”
Inches
Water
Content
Gal.
Max.
Water
Working
Pressure
OWB-9 .60 90,000 76,500 66,500 522 527 7 24-1/4 5.5 60PSI
OWB-15 1.0 150,000 127,500 110,800 875 716 7 34-1/4 8.2 60PSI
OWB-25 1.7 250,000 212,500 184,700 1,450 902 7 44-1/4 10.8 60PSI
OWB-35 2.4 350,000 297,500 258,600 2,030 1654 10 52 28.5 75PSI
OWB-50 3.3 500,000 425,000 369,500 2,900 1831 10 57 31.7 75PSI

Table 1.

NOTES: 1. Net ratings shown are based on a piping and pick-up allowance of 1.15. 2. Net ratings in sq. ft. are based on 170 deg F average water temperature in radiators. For higher water temperatures, select boiler on basis of net ratings in BTU/HR. 3. Firing rate in G.P.H. is based on oil having heat value of 150,000 BTU/GAL. 4. 4% reduction of output for every 1,000 ft. of elevation.
Installation, Operation, And Service Instructions 13