Combustion Air Calculation For Water Heater

Water heater space heater range other total total 1000.

Combustion air calculation for water heater. The calculation is very simple. Increased heating system operating cost spending more on heating oil than necessary damage to oil burner components backpressure heat can destroy an ignition transformer. Multiply that by 50. To properly size the combustion air openings add the input of all fuel burning equipment inside the boiler room.

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. For instance outdoor air for combustion according to codecheck is. The total net free area of the openings shall be equal to 1 square inch per 500 btuh of the equipment rating. Use the simple formula below to calculate the amount of combustion air required by those appliances.

Length width height room volume. Proceed to either part a part b or part c. Combustion air standard method alternate calculation method step 1. Water heater and a 200 000 btu hr.

So the room needs to have a volume of 120 x 50 or at least 6 000 ft 3. Let us assume we have a 40 gal 40 000 btu hr. So the combined input rating is 120 when measured in 1 000 btu hr. Calculate the room volume.

38 000 69 000 x 50 ft 1 000 btu hr 5350 ft. Length x height x width volume in cubic feet. Boiler for a total of 240 000 btu hr. For all air from inside the structure.

There is more than one formula. Water heater btu s 38 000 furnace btu s 69 000 107 000 btu s. For pass through openings between adjacent spaces. Sizing combustion air openings step 1.

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. Enter the input ratings of all appliances in table 1. Find the total btu being fired in the space in question. If using outside air source only opening x must be min 40 sq in 120 000 3 000.

Calculate the room volume. Where all air is to be taken from the outdoors divide the total input of all gas appliances in the space by 4000. 1000 sf x 6 5 feet high 6 500 cubic feet insufficient combustion air. In a room with two vertical openings with metal louvers.

Find the volume of space in question using this formula. The room shall have not less than 1 cubic foot of volume per 15 btuh total equipment load. Appliance btus 120 000. Either draw combustion air from entire basement or outside air.

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.