FIELD CONTROLS CAS-6 Combustion Air System Instruction Manual
- June 1, 2024
- FIELD CONTROLS
Table of Contents
- FIELD CONTROLS CAS-6 Combustion Air System
- ITEMS INCLUDED:
- READ THESE INSTRUCTIONS CAREFULLY AND COMPLETELY BEFORE PROCEEDING WITH
- GENERAL SYSTEM OPERATION
- INSTALLATION SAFETY INSTRUCTIONS
- SIZING AND SETUP
- Table 1
- INSTALLATION
- INSTALLATION OF INTAKE AIR STARKAP
- INSTALLATION OF DUCT
- INTERNAL WIRING CONNECTIONS FOR THE CAS UNIT
- EXTERNAL WIRING CONNECTIONS
- MAINTENANCE
- REPLACEMENT PARTS
- Specifications:
- Warranty
- FAQ:
- Read User Manual Online (PDF format)
- Download This Manual (PDF format)
FIELD CONTROLS CAS-6 Combustion Air System
INSTRUCTION MANUAL
Model: CAS-6, CAS-6SK, CAS-7, and CAS-7SK
This product is designed for use with any oil or gas fi red furnace, water heater, or boiler with 24 VAC or 120 VAC control systems. It may also be used with millivolt water heaters and more than one appliance. The CAS unit mechanically draws air into a structure and disperses it near the combustion air intake of an appliance. Refer to Diagrams A & B for guidance in setting up the CAS system based on the size and length of the connecting duct work and the input rating of the appliance.
ITEMS INCLUDED:
- 1- CAS Unit (ETL Listed) “Fan-In-A-Drum”
- 1- Star Kap (only on SK Models)
- 2- Mounting Brackets for CAS Unit
- 2- Wire/Conduit connectors
- 1- 24VAC Control Relay (SPDT)
- 1- 120VAC Control Relay (SPDT)
READ THESE INSTRUCTIONS CAREFULLY AND COMPLETELY BEFORE PROCEEDING WITH
THE INSTALLATION.
This device MUST be installed by a qualifi ed agency in accordance with the manufacturer’s installation instructions. The defi nition of a qualifi ed agency is: any individual, fi rm, 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.
Please retain these instructions after installation.
Installed By:_ Phone:___ Installation Date:___
GENERAL SYSTEM OPERATION
1. The thermostat (wall thermostat, or aquastat) calls for heat and energizes
a relay which activates the 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 fi re. If the appliance is power vented, the venter will typically
activate before the CAS unit.
2. After the heating requirement has been satisfi ed, the thermostat circuit
will open and deactivate the burner and CAS unit.
3. For power vented systems with a post purge device, the power venter will
operate for a period of time determined by the post purge timer setting after
the burner has shut off to purge remaining fl ue gases from the vent system.
INSTALLATION SAFETY INSTRUCTIONS
CAUTION: This device must be installed by a qualifi ed installer in accordance with the manufacturer’s installation instructions.
1. This combustion air system must be installed by a qualifi ed installer.
“Qualifi ed Installer” shall mean an individual who has been properly trained
or a licensed installer.
2. Plan the system layout before installation to avoid the possibility of
accidental contact with concealed wiring or plumbing inside walls.
3. Disconnect power supply before making wiring connections to prevent
electrical shock and equipment damage.
SIZING AND SETUP
Diagram A shows the maximum equivalent length and size of duct pipe that should be used when installing the CAS-6 system; Diagram B shows the same for the CAS-7. Using this table will help ensure that the proper amount of air is drawn into the structure as needed by the appliance. The defi ned regions shown correspond to the CAS’s airfl ow characteristics when using various sizes of duct pipe for the CAS-6 and CAS-7. Follow the guidelines below to properly size and set up the CAS system.
1. Determine the input fi ring rate of the appliance, or the total fi ring
rate of multiple appliances that will be used.
2. Determine the location of the CAS unit according to the guidelines in the
Installation section.
3. Determine where the intake air StarKap will be located based on the
recommendations in the Installation section.
4. On Diagram A or B (as appropriate), locate the point that corresponds to
the fi ring rate along the horizontal axis and draw a vertical line through
this point.
5. The line should pass through at least one of the pipe size regions on the
table. The regions correspond to the maximum equivalent lengths of the given
diameter duct pipe that will be adequately sized for the application.
6. Calculate the equivalent length of the smaller diameter duct pipe that may
be used with the particular CAS system, including elbows, reducer/increaser
and other fi ttings (except the StarKap, see the Field Controls Contractor
Reference Guide). The eff ects of the StarKap are already fi gured into the
diagram,
so do not attempt to include any value for the StarKap in your calculation for
equivalent length. Draw a horizontal line through the point corresponding to
the equivalent length on the vertical axis.
7. Locate the intersection of the two drawn lines. If the intersection lies
in the region for the equivalent length of pipe for which the equivalent
length was calculated, then that diameter of duct pipe will be of suffi cient
size for the application. If not, then repeat step 7 using a larger diameter
duct, then proceed to step 9.
8. If the intersection of the two lines falls into the larger duct region,
then that diameter duct will be of su ffi cient size for the application. If
it falls to the right of the larger pipe region, then even larger pipe or
additional CAS units will be required for the application. For assistance in
this case, call Field Controls Technical Support at
1-800-742-8368.
Example: An oil fi red appliance fi ring at 10.5 gph where a CAS-7 unit needs to be placed at a location requiring 80′ of pipe from the StarKap, using two 90o elbows:
From Diagram B, a vertical line is drawn through the point at 10.5 gph on the
Oil Firing Rate scale. For 80 feet of 10″ pipe, two 90 degree elbows, and two
increaser/reducers, the equivalent length is 80 + 18 + 18 +
6 + 6 = 128′ of equivalent length. A horizontal line drawn through the point
at 128′ on the Equivalent Length scale intersects the vertical line in the 12″
duct region of the diagram. Since the intersection is not in the 10″ duct
region, recalculate the equivalent length using 12″ duct: 80 + 21 + 21 + 7 + 7
= 136′ of equivalent length. A horizontal line drawn through the 136 point on
the Equivalent Length scale intersects the vertical line within the 12″ duct
region of the diagram; therefore, 12″ duct will be of suffi cient size for the
application.
Equivalent Feet for Vent Pipe Fittings
Vent PIpe Fittings| Vent Pipe Diameter
8”| 10”| 12”| 14”
Tee| 50| 63| 75| 89
Y-Connection| 26| 32| 39| 45
90° Elbow| 14| 18| 21| 25
45° Elbow| 7| 9| 10| 13
Table 1
MAXIMUM EQUIVALENT LENGTH OF PIPE, INCLUDING STARKAP ®
CAS-6 OIL
(gph)| CAS-6 GAS
(BTU/hr)| 8″ duct| 10″ duct| 12″ duct
3| 420,000| 410| 1253| 3119
3.25| 455,000| 344| 1051| 2616
3.5| 490,000| 291| 890| 2217
3.75| 525,000| 249| 760| 1893
4| 560,000| 214| 653| 1627
4.25| 595,000| 185| 584| 1405
4.5| 630,000| 160| 489| 1217
4.75| 665,000| 139| 424| 1057
5| 700,000| 121| 369| 919
5.25| 735,000| 105| 321| 800
5.75| 805,000| 79| 241| 601
6| 840,000| 58| 176| 519
6.50| 910,000| 49| 151| 377
CAS-7 OIL
(gph)| CAS-7 GAS
(BTU/hr)| 10″ duct| 12″ duct| 14″ duct
6| 840,000| 469| 1167| 2523
6.5| 910,000| 381| 948| 2050
7| 980,000| 311| 776| 1678
7.5| 1,050,000| 256| 637| 1378
8.25| 1,155,000| 191| 476| 1029
9| 1,260,000| 142| 354| 766
9.75| 1,365,000| 104| 260| 563
10.5| 1,470,000| 74| 186| 403
11.25| 1,575,000| 51| 127| 274
12| 1,680,000| 31| 78| 207
12.75| 1,785,000| 15| 39| 114
12.88| 1,803,000| 13| 33| 72
INSTALLATION
PLACEMENT OF THE CAS UNIT
The motorized CAS unit should be located on a fl at horizontal surface near the combustion air intake of the appliance. 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.
INTAKE AIR STARKAP LOCATION
The StarKap should be located on an outside wall or roof maintaining
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 StarKap should be located at
least 10′ from a building exhaust outlet, equipment vent, or chimney
termination.
INSTALLATION OF INTAKE AIR STARKAP
After determining the location of the StarKap, cut an appropriately sized hole in the wall or roof, taking precautions to avoid interference with wiring or other plumbing in the structure to be cut. Pre-attach a short length of duct to the StarKap if necessary. Insert the StarKap and secure with appropriate fasteners. Flash in the opening in accordance with local building codes.
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 StarKap. If using pipe of diff erent diameter than the CAS component connections, attach increaser/ reducer fi ttings as close to the CAS unit and to the StarKap as possible. The duct should be supported with appropriate mounting straps from fl oor joists, walls, or other solid structures. The straps should be placed so as to keep the duct work out of passageways. (See Figure 2) For best performance, install elbows or tees no closer than 3 pipe diameters from the inlet of the CAS unit.
WIRING
Wire the CAS unit in accordance with the National Electrical 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 20 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 higher, according to the installation environment.
1. Remove the wiring access cover to access the wiring terminals.
2. Select the appropriate control relay for the appliance control system
voltage from the two relays supplied with the CAS system (see illustration).
Use the 24VAC relay for a 24V control system (typical gas-fi red),
or the 120VAC relay for a 120V control system (typical oil-fi red). Install
the selected relay into the socket provided on the wiring panel, and secure
with the wire retaining clip.
3. Use the enclosed conduit connectors or like connectors to route the
appropriate wires through the CAS housing. The incoming ground wire must be
attached to the green grounding screw located 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. Such as when a fi gure refers to a CK-60 series kit, a CK-60, 61, 62,
etc. may be used. If further information or additional wiring diagrams are
needed please consult Field Controls’ technical support.
INTERNAL WIRING CONNECTIONS FOR THE CAS UNIT
Refer to Figure 3 for the internal wiring of the CAS-6/7 unit.
EXTERNAL WIRING CONNECTIONS
Refer to Figure 4 for typical 120 VAC oil fi red burner or Figure 5 for 24 VAC
gas fi red burner connections that should be used when connecting the CAS
unit. Refer to Figure 6 for connecting a single 120 VAC appliance
to the CAS, or Figure 7 for 24 VAC. The three wires BURNER, WHITE, and ORANGE
in Figure 4 correspond to the same wires shown in Figures 6 & 10. The three
wires labeled 1, 2, and 3 in Figure 5 correspond to the same wires shown in
Figures 7-9. Refer to Figures 8-10 for connecting multiple appliances to one
CAS unit. Note that an RJR-5 or RJR-6 relay and/or a CAC-24, CAC-120 or DIP-1
are required on certain multiple-appliance applications. Figure 11 shows how
the pressure switch port on the CAC/DIP-1 should be attached to the CAS. Note
that the correct 1⁄4″ plastic tubing on the top of the CAS unit must be cut
and a 3-way male barb TEE suitable for 1⁄4″ tubing installed as shown in order
to connect the CAC pressure port/DIP-1.
MAINTENANCE
1. Inspect the system annually to ensure proper operation by observing that
the fan activates when a call for heat occurs and deactivates when the call
for heat is satisfi ed.
2. Disconnect power to the CAS unit and repeat Step 1. NOTE: The unit should
not run and the appliance should not fi re in this condition.
3. Inspect the duct pipe for loose joints, damage, and security to the CAS
unit and StarKap.
4. Clear any obstructions, if present, from the inlet of the StarKap and the
outlet of the CAS unit.
5. Periodically, the fan blade chamber may need cleaning. First, disconnect
the power supply to the CAS. Next, disconnect the duct pipe from the unit.
Then remove the top pan and clean the fan housing area as needed. Reattach the
top pan, reconnect the duct pipe and the power supply.
CAUTION: A minimum clearance of 1″ must be maintained between the bottom of the fan blade and the top of the metal surface underneath. FAILURE TO MAINTAIN THIS CLEARANCE MAY RESULT IN A FIRE HAZARD AND WILL VOID THE WARRANTY.
REPLACEMENT PARTS
The following items are available for replacement, if needed. In order to replace these parts, power must be disconnected and the unit must be disassembled. If this is necessary, take note of the positions and locations of whatever items that may need to be removed to replace other items. If in doubt, please consult Field Controls Technical Support at 1-800-742-8368.
MODEL | ITEM DESCRIPTION | PART NUMBER |
---|---|---|
CAS-6 | AC Motor | 46363400 |
Blower Wheel | 46363600 | |
Pressure Switch | 46363500 | |
Timer Relay | 46144700 | |
24 VAC Control Relay SPDT | 46080200 | |
120 VAC Control Relay SPDT | 46111100 | |
CAS-7 | AC Motor | 46363400 |
Blower Wheel | 46363700 | |
Pressure Switch | 46363500 | |
Timer Relay | 46144700 | |
24 VAC Control Relay SPDT | 46080200 | |
120 VAC Control Relay SPDT | 46111100 |
Specifications:
-
Model: CAS-6, CAS-6SK, CAS-7, CAS-7SK
-
Compatibility: Oil or gas fired furnace, water heater, boiler
with 24 VAC or 120 VAC control systems, millivolt water
heaters -
Items Included:
- CAS Unit (ETL Listed) Fan-In-A-Drum
- Star Kap (only on SK Models)
- Mounting Brackets for CAS Unit
- Wire/Conduit connectors
- 24VAC Control Relay (SPDT)
- 120VAC Control Relay (SPDT)
Warranty
For warranty information about this or any Field Controls product, visit: www.fieldcontrols.com/warranty
FAQ:
Q: Can this system be used with both oil and gas appliances?
A: Yes, this product is designed for use with both oil and gas fired appliances.
Q: Is professional installation required?
A: Yes, this system must be installed by a qualified installer to ensure proper setup and safety.