Ventilation; Dehumidification Circuits; Automatic Control Systems; Thermostats - Bard MULTI-TEC W18AAPA Service Instructions Manual

VENTILATION

Many Bard systems have the capability of various ventilation packages available (either factory or field
installed) directly into the basic system. These systems can be described as follows:
1. Barometric fresh air damper
2. Motorized fresh air damper
3. Commercial room ventilator
4. Economizer
5. Energy recovery ventilator
All of these ventilation systems, if installed, are different and are used for different reasons. They may
also have different control strategies. Consult your installer and/or Service Company to determine if your
installation has any of these devices, and for any instructions or maintenance requirements you should
be aware of as the user.

DEHUMIDIFICATION CIRCUITS

Many Bard systems, typically those used in schools or other commercial applications, have a dedicated
dehumidification capability by having a special additional refrigeration circuit (factory installed option
only) in addition to the basic system. These special systems, sometimes also referred to as hot gas
reheat, are designed to control humidity on demand from a humidity controller much the same as the
basic cooling and/or heating system is controlled by a wall thermostat.
Consult your installer and/or Service Company to determine if your installation has any of these devices,
and for any instructions or maintenance requirements you should be aware of as the user.

THERMOSTATS

There are many types of thermostats available to properly control your system, and these can vary
in features and some functions depending upon the type of system (air conditioner, heat pump, etc.)
installed and any special options (ventilation, supplemental heat, etc.) that may be installed.
Approved compatible thermostats are available from Bard Manufacturing Company for all applications,
and since these can vary in numerous features and functions, it is not possible to adequately discuss
them all in this User's Guide. Many installers also install thermostats other than those offered by Bard,
and must determine proper compatibility prior to installation.
In addition, many schools and similar institutions may utilize central energy management systems (EMS)
or direct digital control (DDC) systems.
In all circumstances have your installer, Service Company or building administrator or maintenance
department personnel instruct you as to proper operation of your specific thermostat or temperature
control system.

HUMIDISTATS (HUMIDITY CONTROLLERS)

All systems with dedicated dehumidification (hot gas reheat) circuits also require a humidity controller
(also called humidistat or de-humidistat) in addition to a thermostat for proper control.
The devices may or may not be adjustable, and if adjustable should only be adjusted by the person(s)
responsible for overall building control conditions. Normal settings would be somewhere between

AUTOMATIC CONTROL SYSTEMS

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