Application Brochure
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. (250) 545-7749 Fax. (250) 545-0650
Web Site: www.tekmarcontrols.com
Control Systems
System Operation
All specifications are subject to change without notice.
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A 361-4 03/09
Product design, software and literature are Copyright © 2009 by:
tekmar Control Systems Ltd. and tekmar Control Systems, Inc.
Printed in Canada. A 361-4 03/09.
The Mixing Control 361 provides setpoint control to a heat pump loop. The output of the variable speed injection pump is modulated to
provide a fixed water temperature to the loop, and protect the boiler from flue gas condensation. The boiler operates at the required
temperature in order to satisfy the load.
Heat Source Details The heat source can be either a high mass or low mass non-condensing boiler.
Piping Details Heat pump units are piped into the mixed loop. The variable speed injection pump (P1) is piped in primary / secondary
in order to isolate the boiler loop flow rate from the mixed loop flow rate. The boiler pump (P2) provides flow through the boiler and
ensures flow past the variable speed injection pump take-off.
Mixing Demand When heat is required in the heat pump loop, the switch provides a
Mixing Demand
to the 361. The mixed supply water
temperature is fixed based on the MIX TARGET setpoint. The variable speed injection pump (P1) is then controlled to supply the
required mixed supply water temperature. As the variable speed injection pump ramps up and requires more heat from the boiler, the
boiler is fired to a temperature that is sufficient to satisfy the requirements of the variable speed injection pump. Whenever the boiler is
fired, the 361 aims to maintain the boiler temperature above the BOIL MIN setting. While the boiler is firing, the variable speed injection
pump 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 361.