tekmar 262 Boiler Control Installation - Manual (Page 13)

13 of 36 Copyright © D 262 - 12/08
Section D1—General Setpoint Operation (Mode = —1—)
The 262 can handle setpoint loads which are high temperature loads connected to the boiler
loop that are not heating or DHW loads.
SETPOINT DEMAND
The 262 registers a Setpoint Demand when a voltage between 24 or 240 V (ac) is applied
across the Com Dem and the Setp Dem terminals (3 and 5). Once voltage is applied, the
Setpoint Demand pointer turns on in the LCD. The Setpoint Demand does not turn on the boiler
pump P1. If a setpoint load is used, the installer must make sure that the setpoint device
provides its own flow through the boiler(s).
BOILER TARGET DURING SETPOINT DEMAND (BOIL TRG)
The Boil TRG temperature during a Setpoint Demand is increased to at least the SETPOINT setting. This temperature is maintained as
long as the 262 has a Setpoint Demand.
SETPOINT SETBACK
If the 262 is placed into setback, the Setpoint Demand is ignored if the SETPOINT UnOcc setting is set to OFF. Otherwise, the setpoint
operates normally. If a system override of AWAY is selected, the 262 operates the SETPOINT load at the Occupied setting.
SETPOINT PRIORITY (SETP PRI = BOIL)
For setpoint loads to have priority over the boiler zone(s), set SETP PRI to Boil. If this option is chosen, the boiler pump P1 turns off
during a
Setpoint Demand.
Setpoint Priority Override
In order to prevent the building from cooling off too much or the possibility of a potential freeze up during Setpoint Priority, the 262
limits the amount of time for setpoint priority. As the outdoor air temperature becomes colder, the length of time the 262 provides
Setpoint Priority is reduced. Once the allowed time for priority has elapsed, the 262 overrides the
Setpoint Priority and operates
setpoint and heating simultaneously.
Conditional Setpoint Priority
If the Boil SUP temperature is maintained at or above the required temperature during setpoint generation, this indicates that the
boiler(s) has enough capacity for setpoint and possibly heating as well. As long as the Boil TRG temperature is maintained, setpoint
and heating occur at the same time.
Section D1
Setpoint
Section D —Setpoint (Mode = —1—)
3 4
Com
Dem
DHW
Dem
Setp
Dem
5
24 to 240 V (ac)