Application Brochure

Product design, software and literature are Copyright © 2009 by:
tekmar Control Systems Ltd. and tekmar Control Systems, Inc.
tekmar Control Systems Ltd., Canada
tekmar Control Systems, Inc., U.S.A.
Head Office: 4611 - 23rd Street
Vernon, B.C. Canada V1T 4K7
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 261-1 03/09
Printed in Canada. A 261-1 03/09.
The Boiler Control 261 provides partial or full outdoor reset to four (or more) thermostatic radiator valve zones. Constant circulation to
the zones is provided by the boiler pump (P1). The boilers are staged as required to provide the supply water temperature that satisfies
the load.
Heat Source Details The heat source can be either high mass or low mass non-condensing or low temperature boilers.
Piping Details Thermostatic radiator valve (TRV) zones are piped into the boiler loop. A pressure differential valve (V1) provides a
bypass for the boiler pump (P1) in the event that most of the TRV’s are closed. The boilers are piped in reverse return in order to ensure
equal flow through the boilers.
Boiler Demand When the outdoor air temperature is below the Warm Weather Shut Down (WWSD) setting, the 261 turns on the boiler
pump (P1). The boiler supply water temperature is based on the Characterized Heating Curve settings. The boilers are staged to satisfy
the required boiler supply water temperature. Whenever the boilers are fired, the 261 aims to increase the boiler supply water tempera-
ture to at least the BOIL MIN setting.
All control functions and specifications are listed in the Product Catalog I 000 and Data Brochure D 261.