PIPING LENGTHS
The boiler’s integral circulator provides the water flow from the primary boiler piping, through the boiler and back to the primary system. Pipe diameter 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 piping 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 boiler 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 system, through the boiler and back to a primary boiler system piping. Pipe diameter and length are critical to ensure proper flow through the boiler and secondary piping. The boiler primary piping system must have a primary circulator 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 installed secondary loop to the boiler. Pipe diameter and length are critical to ensure proper flow through the boiler and secondary piping. Temperature 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 temperature 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 recirculated back into the primary heat exchanger. 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 electrical junction box to allow separate power supplies to the pump and boiler controls or the two circuits (pump and controls) can be combined for connection 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 burner 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 satisfied. This will remove any residual heat from the combustion chamber before turning the pump off. See wiring dia- gram shipped with the unit.
PUMP MAINTENANCE: Inspect the pump every 6 months and oil as necessary. Use SAE30
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 direction when installed in 3" (76.2 mm) diameter 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
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