Field Controls CAS-4 User manual

www.ﬁeldcontrols.com

Please retain these instructions after installation.

This device MUST be installed by a qualiﬁed agency in accordance with the manufacturer's installation instructions. The deﬁnition of

a qualiﬁed agency is: any individual, ﬁrm, corporation or company which either in person or through a representative is engaged

in, and is responsible for, the installation and operation of HVAC appliances, who is experienced in such work, familiar with all the

precautions required, and has complied with all the requirements of the authority having jurisdiction.

READ THESE INSTRUCTIONS CAREFULLY AND COMPLETELY BEFORE PROCEEDING WITH THE INSTALLATION.

Installation Date:

Installed By: Phone:

COMBUSTION AIR SYSTEM

MODEL: CAS-4

This product is designed for use with any natural gas or LP burning furnace, water heater, or boiler with a

24 VAC control system. It may be used with a millivolt powered system with additional hardware. It may

also be used with more than one appliance. The CAS unit mechanically draws air into a structure and

disperses it near the combustion air intake of an appliance. If an optional Vacuum Relief Valve (VRV) is

used, the incoming air is tempered before entering the structure’s airspace. Refer to Diagrams A and B for

guidance in setting up the CAS system based on the size and length of the connecting ductwork and the

input rating of the appliance.

ITEMS INCLUDED IN KIT:

1- Motorized Blower

1- 4" galvanized intake air Vent Hood

2- Mounting brackets to secure the CAS to a wall

2- Wire/conduit connectors

1- 4" x 6" Pipe Increaser Fitting

1- 6" Oriﬁce Ring

1- Instruction Sheet

1- High/Low Motor Speed Switch

page 2

Diagrams A and B and Table 1 show the maximum equivalent length and size of duct pipe that should be

used when installing the CAS system. Using these charts will help ensure that the proper amount of air is

drawn into the structure as needed by the appliance. The deﬁned regions shown correspond to the CAS's

airﬂow characteristics when using 4" and 6" diameter sheet metal duct pipe and the included oriﬁce ring.

Follow the guidelines below to properly size and setup the CAS.

Determine the maximum input ﬁring rate of the appliance, or the maximum total ﬁring rate of multiple1.

appliances that will be used.

Position the motorized CAS unit according to the guidelines in the Installation section.2.

Determine where the intake air vent hood will be located based on the recommendations in the3.

Installation section.

The CAS is equipped with a High/Low motor speed control switch. When calculating the maximum4.

equivalent feet, determine which speed is appropriate for the application. (Refer to Diagram A or B or

Table 1)

Calculate the total equivalent length of duct pipe including elbows and ﬁttings needed to connect the5.

CAS unit to the vent hood. (Refer to Diagram A or B or Table 1)

On Diagram A or B, locate the point that corresponds to the ﬁring rate along the horizontal axis and the6.

equivalent length of the duct pipe along the vertical axis, if using for make up air.

The point should fall within one of the three regions on the table. Each region corresponds to a duct pipe7.

diameter of 4", 4" using the oriﬁce ring, and 6" respectively. If the point falls near the rightward border

of a particular region then the VRV is not necessary. If the point falls away from the rightward border,

then a VRV is needed to reduce the amount of air drawn in.

GENERAL SYSTEM OPERATION

The thermostat (wall thermostat, or aquastat) calls for heat and energizes a relay which activates the1.

CAS unit. After the CAS fan has come up to speed, an internal air pressure switch closes and completes

the circuit to allow the burner to ﬁre. If the appliance is power vented, the venter and CAS activate

simultaneously. After the CAS comes up to speed, a pressure switch in the unit closes and allows the

appliance to ﬁre.

After the heating requirement has been satisﬁed, the thermostat circuit will open and deactivate the2.

burner and CAS unit.

For power vented systems with a post purge device, the power venter and CAS operate for a period of3.

time after the burner has shut off to purge remaining ﬂue gases from the vent system.

INSTALLATION SAFETY INSTRUCTIONS

CAUTION: This device must be installed by a qualiﬁed installer in accordance with the manufacturer’s

installation instructions.

This combustion air system must be installed by a qualiﬁed installer. “Qualiﬁed Installer” shall mean an1.

individual who has been properly trained or a licensed installer.

Plan the system layout before installation to avoid the possibility of accidental contact with concealed2.

wiring or plumbing inside walls.

Disconnect power supply before making wiring connections to prevent electrical shock and3.

equipment damage.

SIZING AND SETUP

page 3

EXAMPLE: A gas ﬁred appliance ﬁring at 100,000 BTU/hr. where the CAS unit needs to be placed 30

equivalent feet from the intake hood.

From Diagram A or B, the point at 100,000 BTU/hr. on the Gas Firing Rate scale and 30 equivalent feet

falls in the 4" Duct, Hood, and Oriﬁce Ring region. The point is approximately 2⁄3of the horizontal distance

between the left and right boundary of the region. The left boundary is the edge of the graph, the right

boundary is the diagonal line that says 4" Duct, Hood & Oriﬁce Ring. Therefore, place the Oriﬁce Ring into

the inlet of the CAS so that it sits on the ledge above the fan. It does not matter which way the Oriﬁce Ring is

turned as long as it is pushed down against the ledge completely. Use 4" diameter pipe to connect the vent

hood and the CAS unit. Install a VRV and the included 4"x 6" increaser on top of the CAS unit and adjust the

balance weight to 2⁄3of the distance of its full adjustment range from its minimum setting. The minimum setting

is with the balance weight turned all of the way counterclockwise.

TOTAL INPUT OF APPLIANCE MAXIMUM EQUIVALENT FEET OF INSTALLATION

CAS-4, 4mV Gas

(BTU/hr.)

4" Duct And Hood w/

Restrictor

4" Duct and 4"

Intake Air Hood

6" Duct and 6"

Intake Air Hood

HI LOW HI LOW HI LOW

50,000 300 300 300 300 300 300

75,000 300 300 300 300 300 300

100,000 300 300 300 300 300 300

125,000 300 220 300 220 300 300

150,000 174 108 232 118 300 300

175,000 99 48 152 63 300 300

200,000 52 14 102 32 300 300

225,000 20 NA 68 13 300 239

250,000 NA NA 45 NA 300 150

300,000 NA NA 16 NA 300 53

350,000 NA NA NA NA 193 8

400,000 NA NA NA NA 109 NA

450,000 NA NA NA NA 56 NA

Draw a horizontal line on Diagram A or B that passes through the point located in step 5. The position of8.

the point along this line relative to the left and right borders of the region it falls into indicates the relative

position that the balance weight of the VRV should be adjusted to. If the point falls near the leftward

border of a region, then the VRV balance weight should be adjusted to its minimum position. This

corresponds to turning the balance weight screw as far counterclockwise as possible.

Table 1

page 4

LOW SPEED SIZING CHART

100

150

200

250

300

50 100 150 200 250 300 350 400

GAS INPUT FIRING RATE (1000BTU/hr.)

MAX. EQUIVALENT DUCT LENGTH (ft.)

0.0 0.50 1.00 1.50 2.00 2.50

OIL INPUT FIRING RATE (gallons per hour)

(1 gallon oil/hr = 140,000 BTU/hr.)

6" Duct &Hood

4" Duct &Hood

4" Duct &Hood w/ Orifice

Diagram A

Diagram B

page 5

PLACEMENT OF THE CAS UNIT

The motorized CAS unit should be located on a ﬂat horizontal

surface within the same space as the appliance and within

3' of the combustion air intake as possible. Two mounting

brackets are provided for securing the unit against a solid

structure, such as a wall, column, or the side of the appliance

itself. Use the included screws to attach the brackets to the

CAS housing as shown in Figure 1. Secure the brackets to a

solid structure with appropriate fasteners. It is not required to

use the brackets as long as the unit is located so that it may

not be bumped, moved, or tipped over. The optional Vacuum

Relief Valve (VRV) should be placed directly on the air inlet of

the CAS unit if using 6". (See Figure 2) Refer to Diagram A to

determine if the VRV is needed. The VRV should be oriented

so that the axis of the swinging gate is horizontal.

ASSEMBLING THE WEIGHTS ON THE VRV

Refer to Figure 3 to assemble the weight assembly, hex nut,

and knurled nut to the VRV gate. After the weight is correctly

positioned, tighten the hex nut against the gate to prevent the

weight assembly from moving during operation.

INTAKE AIR HOOD LOCATION

The 4" galvanized vent hood should be located on an

outside wall maintaining minimum clearances to other intake

and exhaust vents in accordance with the National Fuel Gas

Code, ANSI Z223.1, manufacturer's recommendations and/

or local codes which are applicable. The hood should be

located at least 10' from a power vented exhaust outlet and

should be on the same wall. The intake air hood should be a

minimum of 1' above grade or snowlines where applicable.

INSTALLATION OF INTAKE AIR HOOD

After determining the location of the vent hood, cut a 4

1⁄2" round or square hole in the wall. Insert the vent hood

and secure with appropriate fasteners. Take precautions

to avoid interference with wiring or other plumbing in the

wall to be cut.

INSTALLATION OF DUCT

Refer to Diagram A or B to determine what size pipe is

needed. Connect the duct pipe from the top of the CAS

unit to the Vent Hood in the wall. If using 4" diameter pipe

attach the provided 4" x 6" Pipe lncreaser Fitting to the top

of the CAS unit (or the VRV, if installed). The duct should

be supported with appropriate mounting straps from ﬂoor joists,

walls, or other solid structures. The straps should be placed so as to keep the ductwork out of passageways.

(See Figure 2) A minimum of 12' of pipe should be run to help temper outside air being drawn in. The VRV

may also be installed near the intake air hood and adjusted to mix room air with outside air to help temper

air in cold climates.

INSTALLATION

Figure 1

Figure 2

Figure 3

page 6

WIRING INSTRUCTIONS

Wire the CAS unit in accordance with the National Electric Code and applicable local codes. UNIT MUST

BE GROUNDED. Check the ground circuit to make certain that the unit has been properly grounded. The

wiring should be protected by an over-current circuit device rated at 15 amperes. CAUTION must be taken

to ensure that the wiring does not come in contact with any heat source. All line voltage and control circuits

between the CAS unit and the appliance MUST be wired in accordance with the National Electrical Code

for Class I wiring or equivalent.

Remove the wiring access cover to access the wiring terminals. Use the enclosed conduit connector(s) to

route the appropriate wires through the CAS housing. The incoming ground wire must be attached to the

green colored ground screw near the wire terminals. The following sections describe the most common

applications. The references to various series of control kits implies that any kit in that series may be used. If

further information or additional wiring diagrams are needed please consult Field Controls' technical support.

Black

White

Red

Common

INTERNAL WIRING CONNECTIONS FOR THE CAS UNIT

Refer to Figure 4 for the internal wiring of the CAS-4 unit.

External Wiring Connections

Refer to Figures 5-12 for appropriate wiring method. Figure 4

Figure 5- Chimney Vent Single 24V Furnace

WIRE KEY WIRE COLOR

MOTOR MANUFACTURER W1 W2 W3

McLean Engineering Black Blue Brown

All Others Brown Black Blue

page 7

White

White White

White

Black

BlackBlack

Red

Common

Black

White

Red

Common

Figure 6- Power Vent Single 24V Furnace

Figure 7- Chimney Vent 24V Furnace and 30mV

Water Heater With CK-20FV or CK-20FG

page 8

Figure 8- Chimney Vent 24V Boiler

Figure 9- Power Vent Single 24V Boiler

page 9

Figure 10- Chimney Vent Two 24V Gas Appliances With CAC-24

page 10

Note: Pressure sensing tubes

of CK Control Kits needs to

be “teed” together the hooked

up to SWG, DI, or PV Unit. Note: DIP 1 needs to be

“teed” into pressure

sensing tube on CAS 4.

Figure 11- One Power Venter Two 24V Gas Appliances With DIP-1

Table of contents

Other Field Controls Fan manuals

Field Controls

Field Controls ventCool User manual

Field Controls

Field Controls 46284600 User manual

Field Controls

Field Controls 46255400 User manual

Field Controls

Field Controls VentCool 1.8 User manual

Field Controls

Field Controls 46011100 User manual

Field Controls

Field Controls 46115300 User guide

Field Controls

Field Controls OVD-4 User manual

Field Controls

Field Controls Eliminator User manual

Field Controls

Field Controls FAPV180-AC User manual

Field Controls

Field Controls 4592700 User manual

Field Controls

Field Controls 1575700 User manual

Field Controls

Field Controls 1984600 User manual

Field Controls

Field Controls 46381400 User manual

Field Controls

Field Controls VentCool Tahoe Series User manual

Field Controls

Field Controls 46457000 User manual

Field Controls

Field Controls 4052900 Assembly instructions

Field Controls

Field Controls CAC-120 User manual

Field Controls

Field Controls PVG-100 User manual

Field Controls

Field Controls 206900 User manual

Field Controls

Field Controls 46256400 User manual

Field Controls

Field Controls 46202200 User manual

Field Controls

Field Controls 46311800 User manual

Field Controls

Field Controls 46334200 User manual

Field Controls

Field Controls 46107700 User manual

Popular Fan manuals by other brands

ELTA FANS

ELTA FANS H03VV-F installation guide

Hunter

Hunter 20714 Owner's guide and installation manual

Emerson

Emerson CARRERA VERANDA CF542ORB00 owner's manual

Hunter

Hunter Caraway Owner's guide and installation manual

Panasonic

Panasonic FV-15NLFS1 Service manual

Kompernass

Kompernass KH 1150 operating instructions

VES

VES FALA100/12V/TR Original instructions

Vertiv

Vertiv Liebert DCD user manual

Westinghouse

Westinghouse GFP Series owner's manual

Venmar

Venmar KUBIX HRV PLUS Series user guide

Maico

Maico ECR 31 installation instructions

Sonnenkonig

Sonnenkonig Dinky instruction manual

S&P

S&P ECOWATT HXBR manual

Wider

Wider IMP03369BH instruction manual

Panasonic

Panasonic F-60DHN Operating and installation instructions

Hinkley

Hinkley HIGHLAND instruction manual

Broan

Broan 766BN installation guide

Premium

Premium PFS16022 Use manual