Application Brochure

Product design, software and literature are Copyright © 2000 by:
tekmar Control Systems Ltd. and tekmar Control Systems, Inc.
tekmar Control Systems Ltd., Canada
tekmar Control Systems, Inc., U.S.A.
Head Office: 5100 Silver Star Road
Vernon, B.C. Canada V1B 3K4
Tel. [phone] Fax. [phone]
Web Site: www.tekmarcontrols.com
Control Systems
System Operation
All specifications are subject to change without notice.
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A 356-4 05/00
Product design, software and literature are Copyright © 2000 by:
tekmar Control Systems Ltd. and tekmar Control Systems, Inc.
Printed in Canada. A 356-4 05/00.
Two Mixing Control 356’s provides full outdoor reset to two independent mixed temperatures. The outputs of the variable speed injection
pumps are modulated to provide a mixed supply water temperature to the zones, and protect the boiler from flue gas condensation. The
boiler operates at its operating aquastat temperature.
Heat Source Details The heat source can be either a high mass or low mass non-condensing boiler.
Piping Details Thermostat controlled zone valves are piped into the mixed loops (Mix 1 and Mix 2). The variable speed injection pumps
(P2 and P4) are piped in primary / secondary in order to isolate the boiler loop flow rate from the mixed loop flow rate. The boiler pump
(P1) provides flow through the boiler and ensures flow past the variable speed injection pump take-offs.
Mixing Demand (Mix 1) When heat is required in the Mix 1 zones, the zone valve end switches provide a Mixing Demand to the 356 and
energizes relay R1. Relay R1 then turns on the boiler pump (P1) and mixing system pump (P3). The mixed supply water temperature is
based on the Characterized Heating Curve settings. The 356 then controls the variable speed injection pump (P2) to supply the required
system water temperature. As the variable speed injection pump begins to ramp up, the 356 uses its Boiler contact terminals (5 and 6)
to send a Boiler Enable to the boiler’s operating aquastat. While the 356’s
Boiler contact is made, the variable speed injection pump (P2)
is also modulated to protect the boiler from excessively low water temperatures.
Mixing Demand (Mix 2) When heat is required in the Mix 2 zones, the zone valve end switches provide a
Mixing Demand to the 356 and
energizes relay R2. Relay R2 then turns on the boiler pump (P1) and mixing system pump (P5). The mixed supply water temperature is
based on the Characterized Heating Curve settings. The 356 then controls the variable speed injection pump (P4) to supply the required
system water temperature. As the variable speed injection pump begins to ramp up, the 356 uses its Boiler contact terminals (5 and 6)
to send a Boiler Enable to the boiler’s operating aquastat. While the 356’s Boiler contact is made, the variable speed injection pump (P4)
is also modulated to protect the boiler from excessively low water temperatures.
All control functions and specifications are listed in the Product Catalog I 000 and Data Brochure D 356.