URPOSE
As an established industry leader in the HVAC
market, our philosophy is to add value to
the industry by providing quality products and
services, and to the community by encouraging
participation in its development and progress.
We believe in the application of the Golden
Rule to all our business relationships ... with our
customers, management and employees, stock-
holders, sales representatives, suppliers, govern-
ment, and the community; we believe we have
definite obligations to each.
We also believe that our customers are en-
titled to products and services of the highest
quality at a fair price. Our objective is to provide
complete customer satisfaction. To assure that
we meet this goal in our daily operations,
management and employees subscribe to the
following guidelines:
Engineer, develop, manufacture and
market quality products that meet or
exceed industry standards.
Be a dependable source of supply
and effect timely deliveries to meet
customer needs.
TABLE OF CONTENTS
Introduction ................................................... 1
Air Flow Performance Data ........................... 2
Selection Procedure ....................................... 3
Capacity and Dimensional Data ..................... 4
Performance Data
Quick-Select Sound Data ........................... 5
Discharge Sound Power ............................. 6
Radiated Sound Power ............................... 7
Fan Performance Curves ................................ 8
Electric Heating Coils .................................... 9
Hot Water Heating Coils ............................... 10
Controls ......................................................... 13
Typical Control Configurations ...................... 14
Specifications ................................................. 15
Accessories ..................................................... 15
Applications ................................................... 16
Installation Instructions ................................. 16
Model Coding System ..................................... 17
Due to a continuous process of product improvement, speci-
fications &/or designs are subject to change at any time
without notice and without incurring obligations.
®
Quiet Plus and
®
Zebra are registered trademarks of Warren
Technology.
TABLE OF CONTENTS
INTERMITTENT FAN POWERED UNIT WARREN QUIET PLUS VAV TERMINAL UNITS
1
INTRODUCTION
INTERMITTENT FAN POWERED UNIT
Warren Quiet Plus
®
VAV Terminal Units
Variable Air Volume Terminal Units regulate
the flow of conditioned supply-air into occupied
spaces, to assure that comfortable temperature
levels are maintained at much lower energy
costs than other types of central systems.
Building owners and designers are aware and
concerned about HVAC-system noise levels.
Traditionally-designed VAV terminal units are
often the most significant factor contributing to a
noisy indoor environment. This has a significant
impact on occupant comfort and productivity.
Advanced technology and experience have
been combined by Warren to create a product
line of VAV terminal units which offer a quantum
improvement in VAV design and performance.
Quiet Plus
®
VAV terminal units offer ultra-quiet
operation plus laminar flow and precision control.
Warren Technology has invested extensively
in engineering, product design, and testing in
order to provide system designers with accurate
flow and acoustic performance data.
Innovative, flexible manufacturing processes
governed by modern computer-aided design and
manufacturing (CAD/CAM) systems allow Warren
to adapt quickly to new design requirements.
Model FBI Bypass-Fan Terminals
The Quiet Plus
®
FBI unit feeds VAV supply air
alongside an Intermittent-operation discharge-fan,
through a common discharge opening. The fan
typically cycles on and off with heating demand.
The VAV inlet uses the patented Zebra
®
precision
air valve, with superb acoustic performance, lam-
inar flow, and highly accurate control.
Model FBI has 15 sizes, with cooling-inlet
capacity from 2504200 CFM, and heating-fan
capacity from 2002000 CFM. Electronic (analog
or DDC), electric, or pneumatic controls with
pressure-independent or dependent operation
can be specified with many control sequences.
Warrens Electric and Hot Water coils are
custom-designed for each application to provide
the most reliable, stable operation available. 2
WARREN QUIET PLUS VAV TERMINAL UNITS
AIR FLOW PERFORMANCE DATA
INTERMITTENT FAN POWERED UNIT
CONTROLLABILITY
Warren Quiet Plus VAV Terminal Units have
lower sound levels than conventional units.
Oversizing to attain acceptable sound levels is
unnecessary, so selection may be based on con-
trollability, which ensures maximum performance.
Figure 2 shows the effect of airflow rate and P
S
on controllability for VAV valves. The maxi-
mum operating range of a VAV valve is the
physical distance (linear or rotational) in which it
modulates. The Effective Operating Range is
equal to the maximum operating range minus
the amount the valve must close to compensate
for the system static pressure at the design
airflow rate. Optimum controllability is attained
by selecting the smallest sized unit which meets
the design airflow and sound requirements.
Effective Operating Ranges of less than 50%
are not recommended for VAV terminal units.
Figure 3. Warren Zebra Valve Airflow Performance Data
AIR FLOW
CAPACITIES
Warrens Quiet Plus
VAV Units are offered
in a full range of ter-
minal sizes to accom-
modate most specified
airflow requirements.
Figure 3 shows air-
flow performance data
(full open valve) for
sizes 06-18 inches,
given various static
pressure differences
between the inlet and
outlet of the unit ( P
S
).
Nominal capacities
are based on a P
S
of
0.10 in. WC, 2000 FPM
inlet velocity, 1000
FPM outlet velocity,
and 100% effective
operating range.
Figure 2. Controllability Graph
7000
4000
2000
5000
3000
1500
700
500
150
1000
200
400
300
100
10000
AIR-
FLOW
(CFM)
STATIC PRESSURE DIFFERENCE BETWEEN
INLET & OUTLET OF VALVE ( Ps in. WC)
.02
.05
.20
.03
.07
.3
.04
.15
.4
.7
.10
.5
1.0
1.5
2.0
3.0
NO
MI
NA
L
FL
OW
S
18
16
14
12
10
08
06
STATIC PRESSURE DIFFERENCE BETWEEN
INLET & OUTLET OF VALVE ( Ps in. WC)
NOMINAL
AIRFLOW
EFFECTIVE
OPERATING
RANGE
.1
.2 .3
.5 .7 1.0
2. 3. 4.
50%
60%
70%
80%
90%
100% 110% 120%
100%
90%
70%
60%
50%
40%
30%
20%
15%
10%
80% WARREN QUIET PLUS VAV TERMINAL UNITS
3
SELECTION PROCESS
A. Design data required:
1. Cooling CFM
2. Heating CFM (fan recirculated)
3. Inlet static pressure (ISP)
4. Cooling external duct static pressure loss
(ESP
C
) downstream, not including coil
5. Heating external duct (downstream) static
pressure loss (ESP
H
):
ESP
H
=
×



ESP
Heating CFM
Cooling CFM
C
2
6. P
S
: ( P
S
= ISP ESP
C
)
7. Heating requirements in MBH or kW
8. Maximum allowable NC or Sound Power
9. Details about box installation and room, for
acoustically-critical cases
B. Establish the model designation (see page 17
for other order-code details):
FBIN = No Heat
FBIE = Electric Heating Coil
FBIW = Hot Water Heating Coil
C. Select an inlet size from Table 1 (page 4) that
most closely matches the design cooling CFM.
For optimum controllability, select nominal size
or smaller. Oversizing will degrade the effec-
tive operating range of the unit.
D. Select a unit with that inlet and a recirculating
fan which will deliver the design heating CFM
at the heating external duct (downstream)
static pressure loss (ESP
H
), using the fan
curves on page 8.
E. If an electric heating coil is required, confirm
that the design kW does not exceed the maxi-
mum allowable kW using Formula 6 (page 9).
Use Tables 810 and the Procedure on pages
1012 to select a hot water heating coil if
required, then double-check the fan-curves.
F. Confirm that the unit size selected does not
exceed the maximum allowable NC by using
Quick-Select Table 2 (page 5) for acoustically
non-critical installations, or for critical installa-
tions use tables and formulae in Warrens
Acoustic Applications Guide. If the unit size
selected exceeds the maximum allowable NC
or Sound Power, then select the next larger
unit size and repeat steps D and E.
SELECTION PROCEDURE
INTERMITTENT FAN POWERED UNIT
G. The effective operating range of the unit at
the design conditions should be checked using
Figure 2 (page 2). Calculate the percentage
of nominal airflow using the following formula:
% of Nominal Airflow = Cooling CFM x 100
Nominal CFM
If the effective operating range of the unit
selected falls below 50% on the graph, the
next smaller unit should be considered. Re-
select, and repeat steps D through F.
EXAMPLE (Typical Installation)
A. Given design requirements:
1. Cooling CFM = 1700
2. Heating CFM = 720 (fan recirculated)
3. Inlet static pressure (ISP) = 1.30 in. WC
4. Cooling external duct (downstream) static pres-
sure loss (ESP
C
) = 0.30 in. WC
5. Heating external duct (downstream) static pres-
sure loss (ESP
H
)
ESP
H
= .30
×

ESP
H
= .05 in. WC
6. P
S
= 1.30 .30 = 1.0 in. WC
7. Electric heating coil = 8 kW
8. Maximum allowable NC = 35
9. Installation = not acoustically critical
B. Since the design requires electric heat, the model
designation is FBIE.
C. Select FBIEB12M from Table 1 (page 4).
D. Using the fan curve on page 8 for an FBIEB12M,
confirm that the fan will deliver 720 CFM at
.05 in. WC.
E. Using Formula 6 (page 9), confirm that the re-
quired kW does not exceed the maximum allow-
able (720 CFM
÷

7
0 = 1
0.3
maximum allowable
kW; therefore, 8 kW at 720 CFM is acceptable).
F. Quic