To calculate excess air in a boiler, you first need to determine the theoretical air requirement for complete combustion based on the fuel's composition. Then, measure the actual amount of air supplied to the boiler. The excess air percentage can be calculated using the formula: [ \text{Excess Air (%)} = \left( \frac{\text{Actual Air} - \text{Theoretical Air}}{\text{Theoretical Air}} \right) \times 100 ] This calculation helps in optimizing combustion efficiency and reducing emissions.
return grille size times 2 gives u the amount of cfms u are getting out of the return air grille, i.e. 10x10x2=200cfms...
For a 100,000 BTU furnace, the recommended return air duct size typically ranges from 14 to 20 inches in diameter, depending on the specific design and layout of the HVAC system. The exact size may vary based on factors such as the length of the ductwork, the number of bends, and the overall airflow requirements. It's crucial to consult with an HVAC professional to ensure the proper sizing and efficiency of the system.
If you are looking for an easy method that is not based in scientific data try this: Heating requirement is the same as cooling. To calculate Btu needed to cool look at the furnace for input Btu then multipy that by effeciency of unit. Now think about the coldest day the furnace will provide okay heating such as 5 degrees outside and 68 degrees inside. Subtract those and you have 63 degrees. If you heating Btu was 80000 input and 80% efficient, you need 64000 btu to heat 63 degrees. Do similar math to hottest day and desired inside cool temperature. Maybe 103 degrees outside and 72 degrees inside. That is 31 degrees difference. Use heat math of 64000 Btu for 63 degree which is very roughly 1000 Btu per degree. Apply that to cooling and it's roughly 31000 Btu, or around 2-1/2 ton cooling. Please don't bark at me about the basic nature of my math-I thought I would explain this as a method to start or get an idea. There is a method that accounts for all factors but no way could I explain it. Also, if using electric heat your btu will be about 4.5 per watt and no efficiency applies. The watts can be found on the inside of the furnace above the blower.
quick down and dirty way is the size of your unit (example..4 tons) X 144= the square inches needed for the return vent size or the longer way Max air flow from unit (rated size) / 2.08 cfm/sq in= filter area needed
A "gas furnace" is called a furnace, an "electric furnace" is called an Air Handler
The furnace or air handling unit in the house.
Furnace filters control the amount of particles that pass out of the furnace and into the house. They are essentially the first line of defence in keeping the air in your home clean.
Replacing the furnace filter can improve air flow in your furnace by allowing air to pass through more easily. This helps the furnace operate more efficiently and can improve air quality in your home.
Is there a flame in the furnace. Precisely where is this air coming from and how strong is it?
the arrow points in the direction of air flow.
it's the same as the furnace filter. the air conditioner runs through the furnace to push he cold air. change your furnace filter and you are changing the air filter on the air conditioner
What type of furnace do you have?electric
The furnace air filter is typically located near the air intake of the furnace, which is usually found in the return air duct or near the blower motor. It is important to regularly check and replace the filter to ensure proper functioning of the furnace.
Air flows in a furnace from the return ducts into the furnace, where it is heated and then pushed out through the supply ducts to heat the home.
Regularly replacing the air filter in a furnace helps improve air quality, increase energy efficiency, and extend the lifespan of the furnace.
Your furnace may be blowing cold air and then hot air intermittently due to a malfunctioning thermostat, a clogged air filter, or issues with the furnace's ignition system. It is recommended to have a professional HVAC technician inspect and repair the furnace to resolve the issue.