Install Instructions

16
Figure 7: Purpose of Tappings and Bosses
TABLE 3: PURPOSE OF TAPPINGS & BOSSES
Tapping Location Size, NPT Boss Location Thread Size UNC
Steam Boiler
Less Heater
With Heater
A ¼" - 18 Pressure Gauge
B ¼" - 18 Pressure Limit
C ¾" - 14
Probe LWCO - Std. Plugged
(Float LWCO)
D ½" - 14
Water Gauge Glass (Probe LWCO) Water
Gauge Glass, Pressuretrol & LWCO (Float
LWCO)
E 2" - 11½" Supply (Front & Rear Tappings)
F ¾" - 14 Safety Valve
G 1½" - 11½ Condensate Return
H 1¼" - 11½ Optional Front Return
J 1½" - 11½ Surface Blowoff (Plugged)
K 1" - 11½ Indirect Water Heater Supply
L ½" - 14 Indirect Water Heater Limit
M (4 pcs)
5/16" - 18
Jacket Front Panel, Burner Swing Door
Mounting Bracket
N (2 pcs)
3/8" - 16 Burner Swing Door
P (10 pcs) 5/16" - 18
Jacket Rear Panel, Smoke Box Collar,
Cleanout Covers
Q ¼" - 18 Smokebox Pressure Tapping
R ½"-14
L4006
Operating
Control
Plugged
SECTION II: UNIT-PAK BOILER ASSEMBLY (continued)