Burnham Apex APX399 Installation, Operating And Service Instructions page 46

Vi. Water Piping and Trim
f. Locate and remove 1½" NPT x 2" long black
nipple, 1½" x 1½" x ¾" NPT black tee, ¾" x ¼"
NPT black reducing bushing and Temperature &
Pressure Gauge.
g. Mount the nipple into 1½" FPT boiler supply
tapping (see Figures 1A and 1B), then, install the
tee onto the nipple, making sure ¾" branch outlet
is in horizontal plane and facing the boiler front.
h. Install ¾" x ¼" NPT black reducing bushing
into the tee branch, then, put in Temperature &
Pressure Gauge.
2. APX800 Boiler Model
a. Locate and remove (1) ¾" NPT x close black
nipple, (1) ¾" NPT x 12" black nipple, ¾" NPT
black tee, ¾" FPT x 1" FPT Pressure Relief
Valve, ¾" NPT Drain Valve.
Table 14: Flow Range Requirement Through Boiler
Boiler Boiler
Boiler Supply Return
Model Connection, Connection,
Inch, FPT Inch, FPT
APX399 1½ 1½
APX500 1½ 1½
APX800 2 2
notes: Required Flow (GPM) = ** Output (MBH) * 1000/500 * DT
** Output (MBH) - Select Value for specific Boiler Model from Table 2A or 2B
Using boiler antifreeze will result in higher fluid density and may require larger circulators.
46
A. Factory Supplied Piping and Trim (continued)
Minimum Boiler
Required Head Loss,
Flow (GPM) Ft.
@ 35°F DT @ 35°F DT
21.5 6.1
27.1 6.9
43.4 12.1
Pressure Drop vs. Flow
30
25
20
15
10
5
0
0 10 20
b. Install close nipple into tee branch, then, screw
the assembly into boiler left side front ¾"
tapping making sure tee run outlets are in vertical
plane and parallel to boiler side.
c. Install the ¾" NPT x 12" black nipple into tee
run top outlet.
d. Mount ¾" FPT x 1" FPT Pressure Relief Valve
onto 12" nipple.
e. Install Drain Valve into the tee bottom outlet.
f. Locate and remove 2" NPT steel coupling, 2"
NPT x 2-1/2" long black nipple, 2" x 2" x ¾"
NPT black tee, ¾" x ¼" NPT black reducing
bushing and Temperature & Pressure Gauge.
g. Mount 2" NPT coupling onto 2" MPT boiler
supply stub (see Figure 1C), then, install 2"
NPT x 2-1/2" long black nipple into the coupling
Required Boiler
Flow, Head Loss,
(GPM) Ft.
@ 30°F DT @ 30°F DT @ 25°F DT
25.1 7.9
31.7 8.9
50.7 15.5
500
399
30 40 50
Flow Rate (GPM)
Required Maximum
Boiler Head
Flow, Required
Loss, Ft. @
(GPM) Flow (GPM)
25°F DT
@ 20°F DT
30.2 10.8
38.0 12.1
60.8 20.9
800
60 70 80
Boiler
Head
Loss, Ft.
@ 20°F DT
37.7 15.9
47.5 17.6
76.0 30.0