U.S. Boiler Company Alpine ALP500C, Installation, Operating And Service Instructions

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Vi. Water Piping and Trim
(continued)
B. Piping System To Be Employed.
i. Space heating only - refer to Tables 25 and
26 and Figure 28 “Near Boiler Piping -
Heating Only” as applicable.
ii. Space heating plus indirect water heater(s)
– refer to Tables 25 and 26 and Figure 29
“Near Boiler Piping - Heating Plus Indirect
Water Heater” as applicable.
iii. If piping indirect water heater off boiler (see
Figure 30), be sure that indirect water heater
and domestic hot water circulator are sized
to maintain flow through boiler within limits
shown in Table 24.
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 (19°C).
2. Direct connection of Alpine 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 24.
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.
Table 23: Flow Switch Paddle application
Boiler Flow Switch
Paddle Marking
ALP399C 1
ALP500C E
ALP600C 3
ALP700C 1
ALP800C 1
Alpine boilers are designed to operate in a closed loop
pressurized system. Minimum pressure in the boiler
must be 14.5 psi (100 kPa). Proper operation of the
Alpine boiler requires that the water flow through the
boiler remain within the limits shown in Table 24 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 Alpine 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 installer supplied
boiler circulator. See Tables 25 and 26 for
recommended circulators.
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.
Boiler
Model
Supply
Connection
(in.)
return
Connection
(in.)
DT = 35°F DT = 30°F DT = 25°F
ΔT
= 20°F
Minimum
Required
Flow (gPM)
Boiler
Head
Loss
(ft.)
Required
Flow
(gPM)
Boiler
Head
Loss (ft.)
Required
Flow
(gPM)
Boiler
Head Loss
(ft.)
Maximum
Required
Flow (gPM)
Boiler
Head
Loss (ft.)
ALP399C 1-1/2 1-1/2 21.5 6.1 25.1 7.9 30.2 10.8 37.7 15.9
ALP500C 2 2 27.7 5.2 32.3 6.8 38.8 9.3 48.5 13.6
ALP600C 2 2 33.9 4.7 39.6 6.1 47.5 8.4 59.4 12.4
ALP700C 2 2 39.4 6.0 45.9 7.9 55.1 10.9 68.9 16.1
ALP800C 2 2 43.4 5.9 50.7 7.8 60.8 10.8 76.0 16.1
Notes: Required Flow = Output*1000/(500*ΔT), where flow rate is in GPM, output is in MBH, and ΔT is in °F
Outputs for specific boiler models are provided in Table 3. See also Tables 25 and 26 for near boiler piping sizing. Using boiler antifreeze
will result in increased fluid density and may require larger circulators.
Table 24: Flow Range Requirement Through Boiler