Burnham ALP150 - Manual (Page 65)

65
Tekmar 264 Based Control System (or equal)
Sequence of Operation
The
Tekmar 264 Control (or equal) can control up to four (4) boilers and an Indirect W
ater Heater by utilizing stage firing. When a call for heat is received
by the
Tekmar 264 Control, the control will fire either one or more boilers in sequential firing mode to establish a required reset water temperature in the
system supply main based on outdoor temperature.
The boilers will modulate on their own based on each boiler
’s MCBA
Control and will target a setpoint
temperature to supply enough temperature to the system main to satisfy the desired reset water temperature in the main established by the
Tekmar 264
Control. When a call for Indirect Hot W
ater is generated to the
Tekmar 264, the control will de-energize the zone pump control (ZC terminal), energize the
Indirect pump and sequentially fire the boilers to establish a setpoint temperature in the main for the Indirect Heater using Priority
.
The
Tekmar 264 Control will
disable the stage firing and post purge the Indirect Pump to
reduce the temperature in the Supply Main near the end of
the Indirect Mode to
a point where it
will
need to be when it changes back to Space Heating Mode.
The
Tekmar 264 Control also has the ability to rotate the lead-lag firing of the boilers to establish
equal operating time for each boiler stage.
Figure
5: Modular W
iring Diagram w/T
ekmar 26
Control