Honeywell AUTOMATIC CONTROL SI Edition User Manual

ENGINEERING MANUAL OF AUTOMATIC CONTROL
BUILDING AIRFLOW SYSTEM CONTROL APPLICATIONS
284
C2633
OA
RELIEF
FAN
RA
MIXED AIR
TEMPERATURE
CONTROLLER
STATIC
PRESSURE
CONTROLLERS
OUTDOOR
STATIC
PRESSURE
BUILDING
SPACE
STATIC
PRESSURE
SELECTOR
SUPPLY
FAN
C2630
OA
FLOW
MEASURING
STATION
FLOW
MEASURING
STATION
AIRFLOW
CONTROLLER
AIRFLOW
CONTROLLER
A. FLOW MEASURING STATION IN OUTDOOR AIR DUCT
OA
B. FLOW MEASURING STATIONS IN SUPPLY AND RETURN DUCTS
RETURN
AIR
DAMPER
SUPPLY
FAN
In systems not having a return air fan, the return damper
controls minimum outdoor airflow or building pressurization.
Airflow tracking or direct building static pressure control can
be used to control the return damper, depending on which
parameter is most important. See Figure 35 for airflow tracking
and Figure 36 for direct building static pressure control.
C2631
STATIC PRESSURE
CONTROLLER
BUILDING SPACE
STATIC PRESSURE
OUTDOOR STATIC
PRESSURE
OA
SUPPLY
FAN
OA
RELIEF
FAN
RA
MIXED AIR
TEMPERATURE
CONTROLLER
AIRFLOW
CONTROLLERS
SELECTOR
C2632
FLOW
MEASURING
STATION
FLOW
MEASURING
STATION
SUPPLY
FAN
Fig. 37. Mixed Air Control Cycle with Relief
Fan Control Using Airflow Tracking.
Fig. 38. Mixed Air Control Cycle with Relief Fan
Control Using Direct Building Static Pressure.
Fig. 35. Return Damper Control Using Airflow Tracking.
Fig. 36. Return Damper Control Using
Direct Building Static Pressure.
If a mixed air control cycle is required, a relief fan may be
required. In airflow tracking (Fig. 37), the mixed air controller
opens the outdoor air damper above minimum and the relief
fan tracks the outdoor air. In direct building static pressure
control (Fig. 38) the mixed air controller opens the outdoor air
and relief dampers and closes the return damper, causing the
relief fan to eliminate excessive pressure.

Honeywell AUTOMATIC CONTROL SI Edition Specifications

General

Brand	Honeywell
Model	AUTOMATIC CONTROL SI Edition
Category	Control Systems
Language	English