tekmar 260 Boiler Control - Manual (Page 4)

Copyright © D 260 -
03/09
4 of 20
Sequence of Operation
Section A
General Operation
Page 4
Section B
Boiler Reset
Page 5-8
Section C
DHW
Page 8-10
Section A —General Operation
POWERING UP THE CONTROL
When the Boiler Control 260 is powered up, the control displays the control type number in the LCD for 2 seconds. Next, the software
version is displayed for 2 seconds. Finally, the control enters into the normal operating mode and the LCD defaults to displaying the
current outdoor air temperature.
OPERATION
The 260 operates a single on / off heat source to control the supply
water temperature to a hydronic system. The supply water temperature
is based on either the current outdoor temperature, or on a DHW target.
Outdoor Reset
The 260 calculates a supply temperature based on the outdoor air
temperature. The 260 uses a
Characterized Heating Curve and op-
tionally indoor temperature feedback from an indoor sensor in this
calculation.
DHW Control
When a demand signal from a Domestic Hot Water (DHW) system is
present, the control will operate the boiler to maintain the supply wa-
ter temperature at 180
°F (82°C). Refer to section C.
EXERCISING
The 260 has a built-in exercising function. If a pump or valve that is connected to the control has not been operated at least once every
3 days, the control turns on the output for 10 seconds. This minimizes the possibility of a pump or valve seizing during a long period
of inactivity. While the control is exercising, the
Test LED flashes.
Note: The exercising function does not work if power to the control, valves, or pumps is disconnected.
SETBACK (UNOCCUPIED)
To provide greater energy savings, the 260 has a setback capability. With setback, the
supply water temperature in the system is reduced when the building is unoccupied. By
reducing the supply water temperature, air temperature in the space may be reduced
even when thermostat’s are not turned down. Any time the
UnO Sw (13) and the Com (14)
terminals are shorted together, the control operates in the unoccupied (Night) mode. When
in the unoccupied (Night) mode, the UNOCC segment is displayed in the LCD. The 260
adjusts the supply water temperature based on the UNOCC settings made in the control.
FACTORY DEFAULTS
The control comes preset with several factory defaults. These defaults are based on the terminal unit selection (see section B2). To fine-
tune building requirements, these defaults may be changed. If a factory default value for a terminal unit is changed, the terminal unit
number will flash when selected in the ADJUST menu.
To reload the factory defaults listed in section B2, power down the control and wait for 10 seconds. Power up the control while
simultaneously holding the
Item and buttons. The terminal unit number should now be displayed constantly in the LCD rather
than flashing.
Outdoor Design
Increasing W
ater
T
emperature
Design Supply
Decreasing Outdoor Temperature
Terminal Unit
Indoor Design
13 14
Timer Switch
UnO
Sw
Com