Burnham Apex APX399 User Manual

47
VI. Water Piping and Trim B. Piping System To Be Employed (continued)
Table 15: Recommended Circulator Models for Apex (APX) Boilers Based on 25°F Temperature Differential
and Up to 75 ft. Equivalent Length Near-Boiler Piping - Space Heating Circulator
Boiler
Model
Boiler Supply
Connection,
Inch, FPT
Boiler Return
Connection,
Inch, FPT
Near-Boiler
Piping Supply
Pipe Size, Inch
Near-Boiler
Piping Return
Pipe Size, Inch
Flow, GPM
@ 25°F Temp.
Differential
Combined Boiler
& Piping Loop
Head Loss, Ft.
* Recommended Circulator
Make & Model
APX399 1½ 1½ 2 2 30.2 12.0
Taco 2400-20 Grundfos UPS
32-80/2 F (second speed)
APX500 1½ 1½ 2 2 37.8 13.9
Taco 2400-30
Grundfos UPS
32-80/2 F (third speed)
or
40-80/2 F (second speed)
APX800 2 2 2½ 2½ 60.8 21.5
Taco 1400-70 Grundfos UPS
50-80/2 F (third speed)
Notes:
* Circulator Models shown are not equipped with internal ow check valve (IFC).
When selecting Circulators with IFC contact Circulator Manufacturer for sizing information.
Near-Boiler Piping Size shown is based on 2 to 5.5 Ft/Sec. velocity range to avoid potential noise and pipe erosion.
outlet, then, attach 2” x 2” x ¾” tee onto the
nipple opposite end, 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.
B. Piping System To Be Employed.
Apex (APX) boilers are designed to operate in a closed
loop pressurized system. Minimum pressure in the
boiler must be 12 PSI. Proper operation of the Apex
(APX) boiler requires that the water ow through the
boiler remain within the limits shown in Table 14, any
time the boiler is ring.
NOTICE
Failure to maintain the ow through boiler within
specied limits could result in erratic operation or
premature boiler failure.
1. Near boiler piping must isolate APX boiler from
system piping via closely spaced tees to insure
specied ow range through boiler any time the
boiler is ring:
a. The ow rate through the isolated near-boiler
loop is maintained by factory recommended and
installer supplied boiler circulator.
b. The ow rate through the isolated near-boiler
loop is completely independent of the ow rate
through the heating system loop(s).
c. The ow rate through the heating system loop(s)
is controlled by installer sized/provided system
loop circulator(s).
d. This piping arrangement can be used either for
space heating-only applications or space heating
with indirect water heater(s) applications.
i. Space heating only - refer to Table 15 and
Figure 36 “Near Boiler Piping - Heating
Only” as applicable.
ii. Space heating plus indirect water
heater(s) - refer to Table 15 and Figure 37
“Near Boiler Piping - Heating Plus Indirect
Water Heater” as applicable.
NOTICE
Where it is not possible to install a separate
boiler loop, the system circulator must be
sized to ensure that the ow through boiler
stays within the dened parameters to prevent
overheating when the boiler is red at it’s full
rated input. Install a ow meter to measure the
ow, or re the boiler at full rate and ensure the
boiler DT does not exceed 35°F.
2. Direct connection of Apex (APX) boiler to
heating system, similar to a conventional boiler, is
NOT RECOMMENDED because:
a. The ow rate through system must be the same
as through boiler and fall within limits specied
in Table 14.
b. Pressure drop through entire system must be
known, added to pressure drop through boiler,
and, a circulator selected to provide required
ow at total calculated pressure drop.
c. It is often very difcult to accurately calculate
the pressure drop through the system.
d. In replacement installations, it may be nearly
impossible to get an accurate measurement of
piping amount and number of ttings in the
system. If system is zoned, the system ow rate
may drop well below recommended minimum
ow when only a single zone is calling for heat.

Burnham Apex APX399 Specifications

General

Brand	Burnham
Model	Apex APX399
Category	Boiler
Language	English