tekmar 369 Zone Control Installation - Manual (Page 5)

Copyright © D 369 -10/00 5 of 32
Relay On Time less heat
Relay On Time
more heat
Cycle Length
Relay On Time
Sequence of Operation
Section A
Heating Operation
Page 5 - 7
Section B
Cooling Operation
Page 7 - 8
Section C
Setback
(UnOccupied)
Page 9 - 10
Section D
tN 1/2 Devices
Page 11
Section A1: General Heating
POWERING UP THE CONTROL
When the Zone Control 369 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 temperature.
ZONING OPERATION
The 369 can directly control the temperature in up to six one stage heating zones, three two stage heating zones, or a combination
of one stage and two stage heating zones. In order to measure the indoor temperature, each zone requires either an indoor sensor
or an RTU. With display RTUs, the desired zone temperature is set using the HEATING adjustment in the Adjust menu of the RTU.
With non-display RTUs, the desired zone temperature is set using the RTU dial. If an indoor sensor is used, the desired zone
temperature is set using the HEATING adjustment in the Zone Adjust menu of the control.
HEATING CYCLE (HEAT CYC)
The 369 operation is based on a cycle length which is adjustable
through the HEAT CYC setting in the Control Adjust menu of the control.
During every cycle, the control turns on each zone relay for a specific
on time. The required on time is calculated based on the PID response
of the zone during the previous cycle period. If the zone requires more
heat, the on time is increased, and if the zone requires less heat, the on
time is reduced. In order to prevent short cycling, the 369 ensures that
the zone relays remain on or off for a minimum amount of time.
PID Zoning Logic
Proportional (P)
Proportional control logic compares the actual zone temperature to the desired zone temperature. Zone relay on time is based on
the difference between the actual temperature and the desired temperature. As the zone temperature drops, the relay on time
increases, and as the zone temperature rises, the relay on time decreases.
Integral (I)
Integral control logic compares the actual zone temperature to the desired zone temperature over a period of time. The longer the
actual temperature is below the desired temperature, the longer the on time for the zone relay will be.
Derivative (D)
Determines how fast or how slow the actual temperature is changing.
P + I + D = PID
If proportional, integral and derivative (PID) control logic is used, the control is more able to prevent excessive temperature
swings and provide a stable room temperature under all conditions. It not only takes into account how much the room temperature
has dropped, but also how long there has been a droop and how fast the temperature is changing.
ZONE CONTROL LOAD STAGGERING AND SYNCHRONIZATION
The 369 staggers the operation of the zones in order to achieve a steady load on the boiler while preventing boiler short cycling.
Multiple Zone Controls can be daisy chained together to increase the number of zones. Each of the Zone Controls synchronizes
its zone operating cycles based on the
Zo In input from the other Zone Controls. This results in a more stable system flow rate and
improved boiler operation. In order for Zone Control synchronization to work properly, the cycle length on each Zone Control must
be equal.
Note: If a Zone Control 367/ 368 or House Control 370 / 371 is used with a Zone Control 369, the HEAT CYC adjustment in the 369
should be set to 15 minutes.
- 01/09
- 01/09