Definition Of Terms - Johnson Controls VMA 1410 Overview And Engineering Manuallines

VMA1400 Series Overview and Engineering Guidelines Technical Bulletin 9

Definition of Terms

Autocalibration
To correct for pressure sensor drifts over time, the VMA has an
Autocalibration mode that automatically compensates for temperature
and humidity effects.
N2 Switches
Single-pole, single-throw switches used to set the N2 address of a
controller.
Room Schedule
A set of information listing all parameters required in a room or zone.
Test and Balance (TAB)
Test and Balance (TAB) is a function performed to ensure the installed
system operates to design specifications. Balancing of the VMA zone
indicates whether the VAV terminal box is able to achieve
minimum/maximum airflow settings. TAB must also be performed for
the air handler and the air duct distribution to the VAV box.
Zones
When designing VMA systems, it is critical to establish zones
correctly to take full advantage of VMA's exceptional accuracy and
rapid response capabilities.
The designer strives for the most uniform indoor environmental
conditions possible. A single thermostatic device (room sensor)
controls each area. Also, you may consider a zone any area where the
load is approximately the same for every square foot of floor space.
Heating, Ventilating, and Air Conditioning (HVAC) system zones fall
into two major categories: exterior zones and interior zones. Exterior
zones are spaces directly affected by outdoor weather conditions.
Interior zones are not influenced by heat losses or outdoor air
conditions. Interior zones usually have cooling or ventilation
requirements only.
Further division of interior/exterior zones is occasionally required to
accommodate different occupancy schedules and/or solar loads.
Variations in internal loading also dictate the selection of separate
zones. For example, in a restaurant, the kitchen has much different
heating and cooling requirements than the customer seating area.