Meridian
Systems
5
Zoning Design Guide
036-21478-001 Rev. A (0802)
How Meridian
Works
Figure 1-1: Meridian
Plus System Overview
First the zone must initiate a vote to the HVAC unit.
This occurs when a zone becomes more than 1 degree
off setpoint. At this time a vote is placed for heating or
cooling. Next the controller evaluates the total cooling
demand or heating demand within the entire building
to see which requirement is more critical. Finally, the
system looks for any priority conditions, which would
take precedence over other zones. All three of these el-
ements working together provide accurate and stable
control of comfort.
Additional control features are taken into account to
provide a very effective control of the system. Some of
these include priority override, supply air temperature
limits, outside air temperature lockouts, and min./max.
control over damper position.
Substantial savings can be realized using the Meridian
Zoning system instead of having to install multiple roof-
top units to accommodate multiple zone requirements.
The Meridian
Zoning system is versatile and can be
used with any packaged roof top unit or split system. It
controls a variety of terminal unit functions including
single duct pressure dependent, pressure independent,
series fan and parallel fan terminals.
The Meridian
control system converts single-zone con-
stant volume rooftop packaged or split system HVAC
units into variable air volume/variable temperature
multiple zone systems. The microprocessor based Zone
Manager calculates the heating and cooling require-
ments for each zone based on real time information re-
ceived from each Zone Controller/Damper. The Zone
Manager then directs the HVAC unit to provide the
appropriate amount of heating, cooling, and ventilation
to satisfy each zone’s requirements. A bypass damper
controlled, by a static air pressure sensor, modulates
to maintain constant duct pressure.
The Meridian
system uses a unique 3 tier approach to
controlling the system:
•
Voting Zones
•
System Demand
•
Priority
This 3 tier system works in an integrated fashion to
maintain proper control of the equipment and effective
control of comfort in the zone.
H
E
A
T
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N
G
C
O
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L
I
N
G
F
I
L
T
E
R
AC Line
Outside Air
Exhaust Air
Supply Air Duct
24 VAC
Local Communication Loop
Network
Comm
Loop
Ground
Fan
Up To 16 Zones
To Other
Meridian Plus
Zone Controllers
Zone #1
Temperature Sensor
Modulating
Bypass Damper
Return Air
Sensor
Static Pressure
Sensor & Pickup Tube
Supply Air
Temperature
Sensor
Computer
(Optional)
Outside Air
Temperature
Sensor
Avoid Direct
Sunlight
Meridian Plus
Zone Manager
Typically Mounted
in the HVAC Unit
Zone #2
Temperature Sensor
With Override and Setpoint Adjust
NORMAL
WARMER
COOLER
OVR
To Other
Meridian Plus
Zone Managers
Remote Link
(Optional)
CommLink II
W
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ASTE
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NC
CO
MM
LINK
II
COMM
LINK
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D
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+
+
+
+
+
+
+
+
+
Zone Damper
Zone Damper
Zone Controller
Zone Controller
24VAC
24VAC
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SIG
DET
RDY
SND
REC
PWR
System Manager
Mixed
Air
Return Air
24VAC
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6
5
4
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01/01/97
03:38PM
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OCCUPIED
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ALARMS
Summary of Contents for Meridian
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