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PIPING LENGTHS
The boiler’s integral circulator pro vides the water flow from the
primary boiler piping, through the boiler and back to the primary
system. Pipe di am e ter and length are critical to ensure proper flow
through the boiler. A 3 inch (76.2 mm) diameter pipe installed from
the primary system to the boiler inlet must not exceed 70 equivalent
feet (21.2 m) in length. The return piping from the boiler back to
the primary boiler pip ing system must also not exceed 70
equivalent feet (21.2 m) in length. Subtract 8 feet (2.9 m) of
equivalent length for each 90° elbow installed in the piping to and
from the boiler.
The secondary loop piping to and from the boiler must have a fully
ported ball valve installed in both the supply and return side piping.
The ball valves must be the same diameter as the installed piping.
The ball valve in the piping supplying water to the boil er will only
be used as a service valve. The ball valve installed in the discharge
from the boiler back to the primary system will be used to adjust
boiler flow and temperature rise to ensure proper performance.
BOILER CIRCULATOR PUMP
LIMITATIONS
The integral circulator provided on this boiler WILLNOT function
as a main system circulator. This boiler was designed for installation
in a primary/secondary piping system. The boiler’s integral pump is
only sized to provide flow in the secondary loop, from the primary
sys tem, through the boiler and back to a primary boiler system piping.
Pipe di am e ter and length are critical to ensure proper flow through
the boiler and secondary piping. The boiler primary piping system
must have a primary cir cu la tor installed in the main system loop to
carry the heated boiler water to the point of use in the main system.
This is a low mass, high efficiency hot water boiler which must have
adequate flow for quiet, efficient operation. The internal circulating
pump will provide this flow for a properly in stalled secondary loop
to the boiler. Pipe diameter and length are critical to ensure proper
flow through the boil er and secondary piping. Tem per a ture rise is the
difference in boiler inlet temperature and boiler outlet temperature
while the boiler is firing. Example: The boiler inlet temperature is
160°F (71.1°C) and the boiler outlet tem per a ture is 180°F (82.2°C).
This means that there is a 20°F (11.1°C) temperature rise across the
boiler. The boiler temperature rise is visible on the Command Display
on the boiler’s front control panel. When the automatic bypass valve
is open, a portion of the heated water is re cir cu lat ed back into the
primary heat ex chang er. Operation of the bypass will yield higher
discharge temperatures from the boiler.
PRIMARY LOOP CIRCULATOR
PUMP SPECIFICATIONS
1. Maximum operating pressure for the pump must exceed
system operating pressure.
2. Maximum water temperature should not exceed
nameplate rating.
3. Cast iron circulators may be used for closed loop
systems.
4. A properly sized expansion tank must be installed
near the boiler and on the suction side of the pump.
CIRCULATOR PUMP OPERATION
(Heating Boilers Only)
The boiler pump should run continuously when the boiler is firing.
External wire leads are furnished in the elec tri cal junction box to
allow separate power supplies to the pump and boiler controls or the
two circuits (pump and controls) can be combined for con nec tion
to one 120 VAC, 20 AMP circuit for both. As shipped from the
factory, the control system will turn on the boiler pump when the
main power switch is placed in the “ON” position and the Run/Stop
switch is in the “RUN” position.
INTERMITTENT PUMP OPERATION
(Optional)
An intermittent pump operation feature is available as an option.
When equipped with this option, the boiler’s integral circulating
pump will cycle on at each call for heat, before the burn er fires.
The pump will continue to operate while the burner is firing. The
pump will run for a 30 second period after the temperature set point
is sat is fied. This will remove any residual heat from the
combustion chamber before turning the pump off. See wiring di a -
gram shipped with the unit.
PUMP MAINTENANCE: Inspect the pump every 6 months and
oil as nec es sary. Use SAE30 non-detergent oil or lubricant specified
by the pump manufacturer.
This high efficiency boiler MUST be installed with a
primary/secondary piping system. This type of system uses the
integral boiler circulating pump to supply flow to and from the
boiler only. This pump is sized based on a specified minimum pipe
diameter and maximum length. These limitations are critical to
ensure proper flow through the boiler and secondary piping. The
length of the secondary piping to and from the boiler to the main
system loop must not exceed 70 equivalent feet (21.2 m) in length
each di rec tion when installed in 3" (76.2 mm) di am e ter pipe.
Each elbow and fitting installed in the piping to and from the boiler
will reduce the available equivalent length of pipe that can be
installed. See Water Connection-Piping Lengths for calculation of
equivalent length of pipe and reductions in length for in stalled
fittings.