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KN INSTALLATION AND OPERATION INSTRUCTIONS
Water piping
The
K N
boiler requires a continuous minimum water flow for proper
operation. The circulator for the boiler must be sized to overcome the
head loss of the boiler and the heating system in order to achieve the
required temperature rise. If the system contains hydronic antifreeze
this must be considered when sizing the pump. The temperature rise
across the boiler must never exceed 100°F
(55.6°C)
.
Boiler flow and pressure drop
Maintain
K N-2
flow rate between 3.6 GPM @ 0.07 ft-hd to 18 GPM @ 1.87 ft-hd
(13.6 to 68.1 LPM)
.
Maintain
K N-4
flow rate between 7.2 GPM @ 0.07 ft-hd to 36 GPM @ 1.9 ft-hd
(27.3 to 136.3 LPM)
.
Boiler and system circulators
See the following pages for suggested piping for
K N
boilers. All circulators are supplied
by the installer, except the factory-installed postpurge circulator on the
K N-2
.
Boiler circulator
— the circulator that flows water through the boiler
K N-2
only.
System circulator
— the circulator that flows water through the system, but not
through the boiler.
Boiler/system circulator
— a circulator that flows water through the boiler and
the system.
Circulator activation
See section 7 of this manual and the
K N
Control manual for instructions on wiring
boiler and system circulators.
The
K N
HeatNet Control provides an isolated contact to operate the
boiler
circulator
(or boiler/system circulator).
The
system circulator
must be activated by a relay supplied by the installer. This relay
is usually activated by the system control or thermostat.
Additional controls
Local codes or job specifications may require the use of additional controls, such as low
water cut-offs, flow switches, and high limit controls. Refer to the
K N
Control manual
for electrical connections for auxiliary controls.
Follow the guidelines below to install typical controls in the piping.
Low water cut-off
When the boiler is installed above terminal units, or when required by applicable
codes, install a low water cut-off in the piping above the boiler. See suggested piping in
the diagrams in this section.
Use a probe-type control when possible.
Flow switch
When a flow switch is required, install the switch in a section of the piping that will
ensure enough flow to operate the switch.
Additional high limit controls
For ASME CSD-1 or Canadian applications, or when required by applicable codes,
install an additional high limit control in the supply piping above the boiler.
Make sure the limit control is set at least 20 °F above the highest operating temperature
of the
K N
boiler.
Boiler piping connections
The boiler supply and return connections are shown in Figure 4.
Both connections are 1-1/4 inch NPT.
Size piping for the flow required. Piping connections to the
K N
boiler should generally be 1-1/4 inch NPT.
System design
Design options
The
K N-2
boiler works well in a single or multiple-boiler
application for any type of system. The following pages include
suggested piping diagrams for the following system options:
• Single boiler, zoning with zone valves (page 13).
• Single boiler, zoning with circulators (page 14).
• Multiple boilers, primary/secondary piping (page 15).
• Multiple boilers, parallel piping, reverse-return (page 16).
• Guidelines for chilled water systems (page 17).
All of the piping diagrams show the suggested piping for
optional indirect-fired DHW tanks. Follow the DHW tank
manufacturer’s instructions for installation and piping. Make
sure to size the DHW circulator and piping to provide the flow
needed for the required recovery capacity.
Pipe sizing
Generally install 1¼-inch piping in the boiler circuit. Size
system and other circuit piping based on a 20°F temperature
drop through the zones. For water-source heat pump systems,
the primary circuit flow rate will usually be based on a 5°F
temperature drop. Such high flow systems must be piped with
the boiler on a separate loop.
Piping guidelines
Support the piping
— All piping and
components must be supported such that no loads
or stresses are applied to the boiler. Allow for thermal
expansion in the piping design and passageways.
The piping diagrams in this manual omit piping
components such as unions. Always install unions
where needed to simplify piping and improve
serviceability.
Circulator requirements
Boiler postpurge circulator
The
postpurge circulator
supplied with the
K N-2
(Figure 4), factory piped between the
boiler supply and return connections, is
NOT
intended for use in the system. It must remain
connected as supplied. The postpurge circulator
is only used by the
K N-2
for postpurge flow to
remove residual heat in the combustion zone. The
postpurge circulator includes an integral check
valve to prevent by-pass flow during operation.
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