Table of Contents
Advertisement
Section A3: Two Stage Heating
TWO STAGE HEATING
In cases where a one stage heating system can not provide sufficient heat, a second stage of heat
from an additional heating terminal can be provided to supplement the first stage. A two stage heating
system therefore has one RTU or indoor sensor controlling two output relays: a Lo stage relay and a
Hi stage relay. If an RTU is used to control a two stage heating zone, the RTU must be connected to
an even tN1 terminal (i.e. tN1 2, tN1 4 or tN1 6), and TWO must be selected through the STG NUM
adjustment in the Zone Adjust menu of the control. If an indoor sensor is used to control a two stage
heating zone, the sensor must be connected to an Indr terminal (i.e. Indr 2, Indr 4 or Indr 6), and
TWO must be selected through the STG NUM adjustment in the Zone Adjust menu of the control.
The odd numbered zone relay becomes the Lo Stage and the even numbered zone relay
becomes the Hi Stage.
Example: An RTU connected between
Com and tN1 2 terminals (20 and 22)
is used to control the output relays Zn
1 and Zn 2. Relay Zn 1 is the Lo stage
output relay and relay Zn 2 is the Hi
stage output relay.
PID Staging Logic
The temperature within each two stage zone is controlled by vary-
ing the on time of the output relays over a cycle length. During light
loads, the 369e cycles the Lo Stage relay on and off. As the load
increases, the Lo stage relay on time increases until it reaches the
maximum of the cycle length. The Hi stage relay is then turned
on and its on time is increased as the load increases. When the
heating load decreases again, the on time of the Hi stage relay
is reduced until the Hi stage relay is turned off completely. The
control then starts to reduce the on time of the Lo stage relay.
Section B: Cooling Operation
Section B1
General
Cooling
Section B1: General Cooling
GENERAL COOLING
The Zone Control 369e is capable of operating a single cooling group to provide either
cooling enable (ENBL) or cooling control (CTRL). This is an adjustable item through the
COOL MOD setting in the Control Adjust menu of the control. In order to prevent short
cycling of the mechanical cooling unit, the 369e ensures the Cooling relay is operated
for a minimum amount of time. The minimum run time (MIN RUN) and minimum off
time (MIN OFF) are adjustable settings in the Control Adjust menu of the control.
COOLING GROUP (CG)
A cooling group is a group of heating zones that are a part of a cooling zone. This
function allows zones which are assigned to the cooling group to be doing cooling,
while zones which are not assigned to the cooling group are heating. A heating
zone can be assigned to the cooling group by selecting CG through the ZN COOL
adjustment in the Zone Adjust menu of the control. Zone 6 (tN1 6 or Indr 6) is always a
member of the cooling group; therefore, there is no option for removing this zone from
the cooling group.
COOLING INTERLOCK (INTRLOCK)
In order to prevent simultaneous heating and cooling, the 369e provides a cooling interlock. Once all the heating zones assigned
to the cooling group have been satisfi ed for a period of time, the control will allow cooling operation to occur. This time is
adjustable through the INTRLOCK setting in the Control Adjust menu of the control. Once any zone assigned to the cooling group
requires heat, cooling operation is terminated.
Section B2
Cooling
Enable
7 of 32
Lo Stage
Hi Stage
Lo Stage
Hi Stage
Lo Stage
Hi Stage
Section B3
Cooling
Control
Adjust
Zone 2
Lo Stage
N
M
L
M
Cycle Length
On
Off
On
Off
On
Off
Adjust
Adjust
Zone
1
© 2003
D 369e - 06/03
Hi Stage
Advertisement
Table of Contents
