Combustion Air Requirements For Water Heater

To properly size the combustion air openings add the input of all fuel burning equipment inside the boiler room.

Combustion air requirements for water heater. So the room needs to have a volume of 120 x 50 or at least 6 000 ft 3. Length width height room volume. Either draw combustion air from entire basement or outside air. Boiler for a total of 240 000 btu hr.

Use the simple formula below to calculate the amount of combustion air required by those appliances. 38 000 69 000 x 50 ft 1 000 btu hr 5350 ft. Let us assume we have a 40 gal 40 000 btu hr. When a residential gas fired water heater is installed in a closet the heater combustion gases must be vented to the outside of the residence and the fresh air needed for combustion must be drawn.

Total the column. Where all air is to be taken from the outdoors divide the total input of all gas appliances in the space by 4000. Enter the input ratings of all appliances in table 1. Example furnace btu s water heater btu s dryer btu s total btu s 80 000 35 000 27 000 142 000 btu s 142 000 btu x 50 1 000 7 100 cubic feet required room size of.

In a room with two vertical openings with metal louvers. We need about one square inch of un louvered unobstructed combustion air intake per 1000 btuh of the oil fired heating boiler furnace or water heater. Calculate the room volume. So the combined input rating is 120 when measured in 1 000 btu hr.

Combustion air standard method alternate calculation method step 1. Water heater btu s 38 000 furnace btu s 69 000 107 000 btu s. Water heater space heater range other total total 1000 step 2. Increased heating system operating cost spending more on heating oil than necessary damage to oil burner components backpressure heat can destroy an ignition transformer.

Water heater and a 200 000 btu hr. 1000 sf x 6 5 feet high 6 500 cubic feet insufficient combustion air. Sizing combustion air openings step 1. What is combustion air.

Calculate the room volume. In this example we ll say that the furnace has an input rating of 80 000 btu hr and the water heater has an input rating of 40 000 btu hr. It is the air necessary for a gas appliance such as a water heater to function properly.