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cas-4 fan in a can, combustion air system

March 2019: Fan-in-a-can Combustion Air Systems Q&A

Common Questions About Field Controls Combustion Air Systems (CAS). Winter is winding down, but you won’t be turning your heat off just yet. In fact, I still get a lot of questions about our CAS (Combustion Air Systems). The CAS is designed to provide combustion air for appliances when direct connection to the burner is not possible, like when the appliance is located in a confined space.
Below are some of the most common questions on the CAS.
Q: How do you size the CAS to the appliance?
A: The best way to size the CAS to the appliance is by the input BTU rating for gas appliances and maximum GPH firing rate for oil appliances. Go to page 25 in our Contractor Reference Guide and refer to the Installation Specs chart.
Q: Which type of burners can be hooked up to the CAS-1?
A: The CAS-1 is designed for the Beckett AFII and NX burner. The CAS-1 can also be used on the Riello 40BF burner.
Q: Can the CAS-2B be used on a Carlin burner?
A: No, the CAS-2B is designed to fit the house of the Beckett AF and AFG burner. The Carlin burner is a different size than the Beckett burner. The CAS-2C is designed for the Carlin EZ-1, CRD, and FRD with firing rates under 2.00 GPH.
Q: Can an oil and gas appliance be hooked up to one CAS unit?
A: Yes, you would need to decide which CAS to use and then add the appropriate CAC or CK control to adapt the other appliance.
Q: Can multiple appliances be hooked up to a CAS unit?
A: If you are using a direct connect CAS unit you would not be able to hook multiple appliances up to the CAS. If you are using the indirect CAS unit such as the Fan-In-The-Can you would need a CAC controller for each additional appliance that is being added to the CAS unit. If you are adding a residential water heater to a CAS unit, you would use the CK-20FV control.
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