22
Meridian
Systems
Zoning Design Guide
036-21478-001 Rev. A (0802)
System Installation
Mounting Of Controllers
All Meridian
Ô
Round Dampers or Rectangular Damper
Kits have the required controllers, actuators etc. fac-
tory mounted in an indoor rated control enclosure. If
you wish to use another manufacturers dampers for zon-
ing control you must purchase Zone or Bypass Pack-
ages from York. These are furnished without a mount-
ing enclosure. Most local codes require these compo-
nents be mounted in an enclosure. If yours does not
require this it is still strongly recommended that you do
mount them in an enclosure. Components that are not
in an enclosure are in danger of being damaged, and
are susceptible to dirt and moisture contamination. You
may furnish your own enclosure or one is available from
York. The part number for the York enclosure is
2ZCE0047001024. This is an indoor rated enclosure. If
the zone mounting location is susceptible to water dam-
age, watertight enclosures can be purchased at any lo-
cal electrical supply. Mounting location for the control-
lers should not violate any local, state or national codes.
System Wiring
Wiring requirements for Meridian
systems can be bro-
ken down into four main categories:
1.) Power Wiring
2.) Communications Wiring
3.) Controller Wiring
4.) Sensor Wiring
Each category should be thoroughly understood and
implemented in order to have a trouble free installa-
tion.
Power Wiring
All Meridian
devices are powered by 24 VAC. It is
possible to power the system using one or more com-
mon transformers or individual transformers for each
device. Possible problems you may encounter using
common transformers to power multiple devices are:
•
If polarity is not maintained between devices,
shorting of the transformer will occur resulting
in damage to the electronics.
•
When using one transformer to power multiple
devices it is possible to lose most or all of your
system if the transformer fails.
•
It is important when powering multiple devices
from one transformer that total VA load and
wiring voltage drops be taken into account for
proper sizing of the transformer and wire.
(See Figure 1-16 on page 26)
It is therefore recommended that in most installations
individual transformers be installed for each device. This
will greatly reduce the possibility of errors and pos-
sible damage to the system.
Power wiring should always be done in accordance with
any local, state, or national codes.
It is also important to note that THE HVAC UNITS
FACTORY TRANSFORMER SHOULD NEVER
BE USED TO POWER Meridian
devices! Normally
transformers on typical HVAC units are sized to only
handle the load of the units factory installed controls. A
separate transformer must be used.
Communication Loops
The Meridian
system utilizes two different communi-
cations loops. The Basic system uses a 9600 Baud RS-
485 communications loop (Local Loop) only. The Plus
system uses two different communications loops. It has
a 9600 Baud RS-485 communications loop (Local Loop)
like the Basic system but also has an RS-485 19200
baud communication loop (Network Loop) that con-
nects the Zone Managers together and connects the
CommLink II communications interface.
Summary of Contents for Meridian
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