Install Instructions
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IM-PR 566442 1114 (Design Manual)
1.12.5 Flow control
Flow may be provided with fixed- or variable-speed
circulators, both of which offer proven performance
in radiant heating systems.
Fixed-speed circulator benefits
• Generally a lower rst cost than variable-
speed pumps
• Good availability of circulators with proven
performance
Variable-speed circulator benefits
• Potential for reduced energy consumption by
reducing flow to meet instantaneous demand
• Less circulators may be required within a
system because one circulator can cover
a large range of pressure drop, which can
occur as circuits open and close
• Higher level of control to satisfy heating loads
• Opportunity for heating system to reach set
point more rapidly after setback events
1.12.6 Zoning
In areas of a building that have large variations in
heating loads or occupancy, zoning can provide
precise control of heat delivery across spaces
while optimizing comfort. Within a radiant system’s
piping, zoning can be provided through the use
of powerheads, zone valves or circulators that
respond to a call for heat.
• Powerheads
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Located on individual manifold circuits
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Provides the opportunity to supply
multiple zones with a single manifold,
allowing for less secondary piping
throughout the building
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Exterior loops can be left to run off
outdoor reset alone rather than powerhead
control, which may provide smaller
temperature swings in the space
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Simple installation when dealing with small
1- and 2-circuit zones
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Single circulator may require less power
consumption than multiple
(CSA B214 Clause 12.5.5)
General
Provision shall be made to control zone ows in
a multi-zone hydronic system where the closing
of some or all of the two-way zone valves can
cause excess ow through the open zones or
deadheading of a xed-speed pump.
Differential pressure bypass valve
When a differential pressure bypass valve is
used for the purpose specied in Clause 12.5.4,
it shall be installed and adjusted to provide
bypass of the distribution system when most or
all of the zones are closed.
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14. ©CSA Group, B214-12. 2012. “Installation Code for Hydronic Heating Systems” Clause 12.5.5
1.12.7 Differential pressure regulation