Carrier ZONE-MIZER 50ME - Manual (Page 5)

and why it’s best.
Low operating costs
On partial load, the Carrier compres­
sors unload cylinders to match com­
pressor output to cooling needed with
up to 6 steps of reduction. To maintain
balanced operation, the hot gas bypass
system diverts hot refrigerant to the
outdoor air cooling coil as needed.
There is no mixing of warm and cold
airstreams in the modular design. Just
that amount of energy required to heat
or cool a given zone is used — and no
more.
Heating is available 3 ways. . .
Electric heating, provided by 2- or
3-stage electric heaters in each module,
gives up to 36 steps of capacity, again
using the minimum amount of energy.
Hot water/glycol heat may be speci­
fied to utilize an already available
heating plant.
Gas heating models utilize inter­
mittent pilot ignition in each module
designed to consume a minimum
amount of energy.
Low»temperature
operating capa­
bility. . .You can use the economizer
cycle with outdoor air for “free cooling,”
as with competing units. However, with
Carrier’s head pressure controlled re­
frigeration system, you can often save
money by using refrigeration to cool
the space instead. So-called “free
cooling” is expensive if a large quantity
of cool outdoor air must be heated for
the zones which do not require cooling.
The Carrier refrigeration system can
operate at outdoor temperatures down
to -20 F. The Carrier modular design,
therefore, is not dependent on an
economizer cycle for cooling at low
outdoor temperatures.
Superior humidity control
One of the major concerns in multizone
applications has been the control of
humidity, especially in schools where
moisture comes from large groups of
people as well as from outdoor venti­
lation air. The basic Carrier design elim­
inates this problem. During mechanical
cooling, all outdoor air that passes thru
the Humidry® outdoor air cooling coil
is dehumidified whenever any zones
require cooling. The air is then further
dehumidified when it passes thru the
zone module cooling coil.
If further dehumidification should be
required for any or all zones, reheat can
be added easily. A humidistat, installed
in the conditioned space to override the
thermostat, energizes the cooling coil
for that zone.
Ease of service
The Zone-Mizer™ Modular Multizone
uses simple, familiar, commercial, ther­
mostatic controls for each module,
eliminating the need for factory experts
and complex start-up and service
procedures. The printed control circuit
board has clearly marked terminals for
easy connection of standard 2-stage
heating and one- or 2-stage cooling
thermostats, which are located in
each zone.
Identical relays plug into the circuit
board. Modules can be easily combined
to serve larger spaces by placing
factory-supplied jumper wires on the
premarked terminals.
The entire control system is neatly
organized in one location. For excellent
accessibility, all circuit breakers project
outside so that any motor can be dis­
connected without opening the high-
voltage box. This often eliminates
the need for separate field-supplied
disconnects.
The handsome Carrier mercury bulb
type thermostats control heating and
cooling modes. They are available with
a locking device which requires an Allen
wrench for access, or you can allow
the zone occupant to set his own
temperature.
Access to the Zone-Mizer Modular
Multizone is thru removable side panels
held in place with simple fasteners. Top
panels may also be removed for com­
plete access to unit interior.
In short, the local installing dealer or
contractor can handle all service and
will have available, from the nearest
Carrier distributor, any parts required.