Combustion Air Systems CAS-4Jr.™

CAS-4 Jr.

CAS-3 (Oil) and CAS-4 (Gas)

These models are designed to provide combustion air for appliances when direct connection to the burner is not possible (when the appliance is located in a confined space). According to NFPA 54 and NFPA 31, an engineered system such as a CAS-3, 4, 6 or 7 may be used to overcome the lack of air in a confined space. The CAS-3 is designed for use with oil appliances. The CAS-4 is for use with gas appliances with 24 VAC gas valve controls. The CAS-4MV is for use with 750mV power pile gas appliances. Each is designed for optimum safety and includes a proving device that won’t allow the burner to engage without the Fan-in-a-Can® operating. Multiple units or additional controls are required for multiple appliance installations. Each is equipped with a two speed control for enhanced versatility.

How the CAS-3 and CAS-4 work

When the thermostat calls for heat, the Fan-in-a-Can® engages and begins drawing air into the structure. When air flow is established, the pressure switch closes. The CAS sends a signal to the appliance, allowing the burner to fire. The Fan-in-a-Can® diffuses the outside air into the room near the burner to ensure adequate air for efficient combustion.

Model

Fuel

Application

Appliance Input

Components

CAS-3

Oil

Any oil heating appliance 120V

See Installation Spec Chart below

4" Intake Air Hood
Fan-in-a-Can®
6" to 4" Reducer
Restrictor Plate

CAS-4

Gas

24V Gas Appliance

See Installation Spec Chart below

4" Intake Air Hood
Fan-in-a-Can®
6" to 4" Reducer
Restrictor Plate

CAS-4MV

Gas

750mV Power Pile Gas Appliance

See Installation Spec Chart below

4" Intake Air Hood
Fan-in-a-Can®
6" to 4" Reducer
Restrictor Plate

CAS-4P

Gas

Boiler with automatic vent damper

See Installation Spec Chart below

4" Intake Air Hood
Fan-in-a-Can®
6" to 4" Reducer
Restrictor Plate
ADA-1



For multiple appliances, the following additional controls should be used.

Model

Description

CK-20FV/FG

Additional 30mV gas water heater control for use with CAS-4 and CAS-4Jr.

CAC-24

Additional 24 Volt appliance for use with CAS-4, CAS-4Jr., CAS-6, and CAS-7

CAC-120

Additional 120 Volt appliance for use with CAS-3, CAS-6, and CAS-7

CAS-4Jr.

Installation Specifications

Total Input of Appliance(s)

Max. Equivalent Feet of Installation

CAS-3 OIL

CAS-4, 4mV, 4P GAS

4" duct & hood w/ Restrictor

4" duct & 4" hood

6" duct & 6" hood

(gph)

(BTU/hr)

HI

LOW

HI

LOW

HI

LOW

-

50,000

300

300

300

300

300

300

.50

75,000

300

300

300

300

300

300

.75

100,000

300

300

300

300

300

300

.90

125,000

300

220

300

220

300

300

1.00

150,000

174

108

232

118

300

300

1.25

175,000

99

48

152

63

300

300

1.35

200,000

52

14

102

32

300

300

1.55

225,000

20

NA

68

13

300

239

1.75

250,000

NA

NA

45

NA

300

150

2.00

300,000

NA

NA

16

NA

300

53

2.50

350,000

NA

NA

NA

NA

193

8

2.75

400,000

NA

NA

NA

NA

109

NA

3.25

450,000

NA

NA

NA

NA

56

NA

CAS-4Jr.™

The Fan-in-a-Can, Jr. is designed for gas appliances up to 110,000 BTU/hr input. A 4” intake Air Hood (IAH) is included along with mounting brackets to secure the Fan-in-a-Can, Jr. to a wall. It may be used with a residential water heater with the addition of control kit CK-20 FV/FG.





Total Input of Appliance(s)

Maximum Equivalent Feet of Duct Pipe

BTU/hr

4" Pipe

5" Pipe

6" Pipe

50,000

230

300

300

60,000

160

300

300

70,000

105

300

300

80,000

70

214

300

90,000

40

122

300

100,000

25

76

180

110,000

15

46

80

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