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Combustion Air Systems

Combustion Air Systems, like Fan-in-a-Can™, provide controlled amounts of outside air for proper combustion.

What are the effects of Insufficient Combustion Air on Draft and Heating Systems? For the proper operation and venting of gas or oil heating appliances, sufficient outside air must be supplied to the structure to make up for the air lost from venting heating appliances, fireplaces, clothes dryers, exhaust fans and other building air losses. An insufficient combustion air system can cause major problems for proper draft and operation of both gas and oil heating systems. For years it has been assumed that when a heating appliance was located in an unconfined area, there was sufficient air for both ventilation and combustion. Today, in most cases that is not true.

New Construction Standards For Air Changes

With new construction, ASHRAE standards for building insulation and energy efficient windows and doors have reduced the amount of air changes per hour. The combustion and make up air requirements in the codes are based on 1/2 air changes per hour. For newer homes and conversion of electrically heated homes, the air changes could be reduced to 1/3 or less air changes per hour. Air problems are most notable on the coldest days when heat loss is the greatest and there is a chance that windows or doors are closed for an extended period of time. When installing new equipment or troubleshooting problem equipment, the first determination that needs to be made is whether the equipment is located in a confined or unconfined space.

Fan In A Can

The CAS-4 Fan In A Can 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 Fan In A Can 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.

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