How much combustion air is needed

Many times, I get high CO readings. We all get the VP of operations personal cell phone number and are urged to call him, anytime, if we see something that is funky. I have done this, many times, and the PE guy agreed with me. Three times new construction he has turned off the gas to the building condos until the combustion air problem is fixed.

At another site that I posted this info at one person stated that they required a password after they downloaded it.

I did not. So give it a try. Recycled Air no ventilation - 50 cubic foot per 1,btu of appliance Horizontal to Fresh - 1sqin per 2,btu of appliance Vertical to fresh - 1sqin per 4,btu of appliance. Where were you 7 years ago when I was looking for this answer?

Can I use the same numbers at sea level and 10, ft above sea level? Do I need to derate the fuel gas? Do I need more combustible air at higher altitude and if so how much?

This is an illustration of burning 1 cubic foot of gas in a standard gas furnace. Figure 5. This shows a structure that is like the structure in the article. Btu Buddy Pesky Refrigerant Leak. He moved on to become service manager for Layne Trane, Charlotte, N. He taught for 15 years at Central Piedmont Community College, part of this time as program director. He had his own business for five years doing installation and service work.

For more information, he can be reached at or thebillj1 gmail. Btu Buddy Notebook is a collection of more than 50 service call scenarios in book form covering both cooling season and heating season troubleshooting. The amount of air required for a water heater depends on the amount of energy the water heater uses. Keep in mind that if there is another gas appliance in the same room, such as a gas furnace, you will need to calculate the amount of air needed based on the combined input ratings of both appliances.

If the water heater needs more air than is available in the room, you will need vents or a louvered door connected to another part of the house or the outdoors. In most cases, you will need two vents, one located within 12 inches of the ceiling and another within 12 inches of the floor.

The proper vent height and size depend on where the air is coming from and whether there are grills or screens covering the vents. If we open a in. That would not be a good thing as critters and birds could come into the room.

So we install a metal louver with a screen in the opening. This will not deliver the same amount of air as a wide-open hole because of the restrictions of the louvers and screen. The louver manufacturer should be able to provide you with the actual free area or aK factor of the louver.

The following are some rules of thumb on free area for other combustion air openings:. You also will need an interlock to verify the fan is operating before the boiler or water heater starts. Many residential boiler installations are relegated into a small closet and expected to work properly. When using indoor air for combustion, the boiler room should have 50 cu.

If the same system as above is using indoor combustion air instead of outside air, the following is the size room we would need. Assuming we have a ft. If the room does not have that much space, you can install a combustion air fan to introduce air to the room. Wire the fan to operate any time the water heater or boiler is operating. I have been inside many boiler rooms where the combustion air openings have been blocked.

As a service technician, I believe we have a duty to explain to the owner the importance of combustion air. I offer to remove the blockage and if they refuse, will put something in writing advising them of the danger.