Section 2 - Product Description; Typical Operation; Ventilation System; Economizer System (Typical) - Pace PAI Installation And Assembly Manual

The AHU features segmented construction, and is fac-
tory assembled. Segment arrangements will vary to suit
the job application as shown in Figure 1 on page 15.
Features of the AHU include:
• Heavy gauge galvanized steel is used on the ex-
terior and interior of the AHU.
• Access doors are provided for accessibility to the
various sections.
• Removable access panels are standard in lieu of
doors on commercial performance AHUs.
• Panels and doors are constructed with double
walls.
• Panels, doors, and structural frame are insulated
with spray-injected foam.

TYPICAL OPERATION

The operation of the AHU is divided into four systems:
1. Ventilation
2. Economizer (Return Air/Mixing Box Section)
3. Heating
4. Cooling
5. Cleaning

Figure 1 - Cutaway Showing Segmented Construction

Form PA102.20-N1

SECTION 2 - PRODUCT DESCRIPTION

Ventilation System

The purpose of a ventilation system is to remove air that
is substandard to creature comfort or a process, and re-
place it with suitable air. Depending on the application,
the system will operate at various specified rates, vol-
umes, and conditions. A ventilation system may employ
an AHU with a supply fan working in conjunction with a
remote exhaust fan(s). A more effective method would
employ a supply fan and an exhaust fan in the AHU.

Economizer System (Typical)

The economizer system typically consists of:
• Outdoor and return air dampers
• Damper actuator
• Enthalpy control
• Minimum outdoor air adjustment
• Exhaust air control
The economizer system provides the first stage of cool-
ing whenever the outdoor air is cool and dry enough to
satisfy the internal cooling demand. The outdoor and
the return air dampers are operated by individual ac-
tuators. As the outdoor air dampers are opened by the
damper actuator, the return air dampers are closed.
15
Installation & Assembly Manual │ PACE
Issue Date: 07/03/2018
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LD13764