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 flow 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 flow through the
boiler remain within the limits shown in Table 14, any
time the boiler is firing.
nOTiCE
Failure to maintain the flow through boiler within
specified 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
specified flow range through boiler any time the
boiler is firing:
a. The flow rate through the isolated near-boiler
loop is maintained by factory recommended and
installer supplied boiler circulator.
b. The flow rate through the isolated near-boiler
loop
is completely independent
of the flow rate
through the heating system loop(s).
c. The flow 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 flow through boiler
stays within the defined parameters to prevent
overheating when the boiler is fired at it’s full
rated input. Install a flow meter to measure the
flow, or fire the boiler at full rate and ensure the
boiler
D
T
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 flow rate through system must be the same
as through boiler and fall within limits specified
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
flow at total calculated pressure drop.
c. It is often very difficult 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 fittings in the
system. If system is zoned, the system flow rate
may drop well below recommended minimum
flow when only a single zone is calling for heat.
Summary of Contents for Apex APX399
Page 65: ...65 VIII Electrical continued Figure 43 Ladder Diagram ...
Page 66: ...66 VIII Electrical continued ...
Page 67: ...67 Figure 44 Wiring Connections Diagram VIII Electrical continued ...
Page 110: ...110 1P 3 1P 2 1P 1 XIII Repair Parts continued 1C 1D 1E ...
Page 116: ...116 XIII Repair Parts continued ...
Page 118: ...118 XIII Repair Parts continued ...
Page 129: ...129 SERVICE RECORD DATE SERVICE PERFORMED ...
Page 130: ...130 SERVICE RECORD DATE SERVICE PERFORMED ...