This is an E- booklet Steve and I put together a few years back. It started out as research to make ourselves more knowledgeable in matters concerning venting. We checked with vent manufacturers about how many cubic feet per minute their vents can vent at very low pressures. They had no idea. They either lost this information decades ago, or never tested at ounces of pressure. So is one vent better than another? How many vents would it take to equal a 3/4'' tapping? If we remove this old antique Hoffman #10 main vent, and I replace it with a single Hoffman #75 thats available today, did I fix the problem or just degrade the system? How much air can a radiator trap pass? These are the questions we had and the answers were lost to history, if they ever existed at all.

So we bought the necessary equipment and started testing vents and traps. Anything we could get our hands on we tested. The word got out and pretty soon boxes from other areas of the country were showing up on our doorstep with air vents and traps for testing. We tested vents for Frank Wilsey (steamhead) out of Baltimore, for John Shea out of Detroit. We have homeowners sending vents for testing. We compiled all these readings into a four page chart. Its available on Dan Holohans web site at heatinghelp.com and the proceeds from its purchase all go to charity. Venting takes on new importance as the cost of fuel rises, and knowing how many vents to use is of tremendous aid when trying to restore a steam systems performance. If you want to know more about venting click this link, Balancing Steam Systems Using a Venting Capacity Chart.