Product Overview

tekmar Control Systems Ltd., Canada
tekmar Control Systems, Inc., U.S.A.
Head Office: 5100 Silver Star Road
Vernon, B.C. Canada V1B 3K4
[phone] Fax. [phone]
Web Site: www.tekmarcontrols.com
Product design, software and literature are Copyright © 2012 by:
tekmar Control Systems Ltd. and tekmar Control Systems, Inc.
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All specifications are subject to change without notice.
Printed in Canada. A 274 - 01/12.
Specifi cations:
The following are the recommended specifications for the Boiler Control 274
The control shall be able to adjust the number of boilers required to operate during a call for domestic hot water heating.
The control shall have the ability to calculate the boiler’s target temperature based on outdoor reset.
The control shall have the ability to set the boiler’s target temperature using an adjustable setpoint.
The control shall have an adjustable warm weather shut down applied to outdoor reset operation.
The control shall be able to operate two primary pumps in standby mode.
The control shall have a proof demand input to proof flow for the primary pump or prove the combustion air damper is open.
The control shall be able to operate one primary pump and one domestic hot water pump during a domestic hot water call.
The control shall have the ability to display the current temperature difference between the return temperature and the supply
temperature, ΔT.
The control shall have an option to rotate the boilers and optionally, the primary pumps based on the accumulated
running hours.
The control shall display the run time of the boilers and optionally, primary pumps.
The control shall use proportional, integral and derivative (PID) logic when modulating the boilers.
The control shall have an adjustable Minimum Supply water temperature setting to help prevent condensation of flue gases
and subsequent corrosion and blockage of the boiler’s heat exchanger and chimney.
The control shall have the option of an automatic differential calculation in order to prevent short cycling of the boilers.
The control shall have the ability to operate boiler pumps.
The control shall have two separate adjustable post purge settings that allow the primary and boiler pumps to run for a set
period after the boiler has been shut off.
The control shall have the option for a fixed lead rotation and when this option is selected, the control shall have an option for
either a first on / first off, or first on / last off modulating sequence.
The control shall have the option for either an alarm output or a combustion air damper output.
The control shall have an adjustable minimum inter-stage delay that can be set manually or calculated by the control.
The control shall have the option of accepting a 0 – 10 V(dc) or 2 – 10 V(dc) input signal from an energy management system
with an adjustable offset.
The control shall have three separate lockable access levels (Advanced, Installer, User) to limit the number of setting adjustments
available to various users.
The control shall have a test button that activates a pre-programmed test sequence testing all the control’s outputs.
The control shall have the ability to show the current outdoor, boiler supply, and boiler return temperatures.
The control shall continually monitor the temperature sensors and provide an error message upon a control or sensor failure.
During extended periods of inactivity, all pumps shall be periodically exercised to prevent seizure during long idle periods.
The control shall include a setback schedule that can be used by the control itself or shared with other tN4 devices.
The control shall have the option to operate as a tN4 system control with a tN4 boiler bus.
The control shall be able to adjust the amount of time Boost will take place to increase the supply water temperature when
coming out of setback.
The control shall be able to disable Zone Load Shedding if that feature is not desirable.
The control shall include an adjustment for the cycle length if connected to a tN4 network.
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