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HVAC/ HYDRONICS 40 NOVEMBER 2014 | FUEL OIL NEWS | www.fueloilnews.com T his article is a follow-up to an article I did just a while ago. This article will include input from one of my internet friends who normally goes by the handle of 'Steamhead.' Many thanks to Frank Wilsey of Towson, Md., for his help on this and for suggesting it. In Part 1 (July), we covered some issues with steam boiler water feeders that can cause boilers to flood. But there are times when the feeder and valves check out okay and the boiler is still flooding. Here are some more things to look for, and you may find you have several small problems instead of one big obvious problem. In addition, some of these can also cause pipe and system banging (also known as water hammer), spitting vents, slow heating, high fuel consumption and other problems. RetuRns When condensate doesn't return as fast as it should and returns to the boiler slowly, the boiler may approach a low-water condition, which will trigger a call for water. With a feeder installed it will kick in and do its job, but when the condensate finally gets back, the boiler will flood. One of the possible causes could be: If the system has wet return lines, they may be partially clogged. You should check for this by removing the main vent and then run water from a hose into the main vent tapping. Note how long it takes for the water to appear at the boiler; it should arrive in less than a minute or so. This is also a good way to flush dirt out of the wet return lines. If you find the wet return is clogged and flush- ing it out doesn't help, you'll need to replace your wet returns. Although you should only use black fittings on your mains and supply piping, including all near boiler steam piping, Frank and I both agree that using copper on returns is a great and fast way to go. Remember that wet returns are just what they are, and if they are filled with water, it's water piping, period. You should always check with the boiler manufacturer just to play it safe; warranties are contracts and both sides have to live up to the contract. What if there are no main vents to remove or hook up to? Let's assume there is no other way to vent air from the steam mains quickly, then it's time to add main vents. Doing so will benefit both you and your customer. To quickly size the vents use a manual from Gerry Gill and Steve Pajek. It's an e-book and one of the best vent- ing references ever. http://www.heatinghelp.com/prod- ucts/Steam-Heating-Books/25/146/Balancing-Steam- Systems-Using-a-Vent-Capacity-Chart-by-Gerry-Gill- and-Steve-Pajek Best of all, all of the proceeds from the book go to charity. ValVes Valves can also create problems, and you must check everything when troubleshooting. Lanthier's Second Law is "assume nothing," so don't, and check it all! On one-pipe systems, check to make sure all of the radiator shut-off valves, Figure 1, are fully open. Some hom- eowners prefer to keep some rooms cooler and adjust their radiator valves in an attempt to do this. Remember that in the one-pipe system the condensate has to go down the same pipe where the steam comes up, and if you restrict the valve opening, water can accumulate in the radiator. If enough water stays in the radiator and doesn't go back to the boiler, the low-water cutoff may call for water from the feeder. A radiator with water backing up in it will probably also bang, with water spit- ting from the vent. This can still happen if a customer shuts a radiator valve completely. The washers in these old valves frequently don't seal completely, which can let some steam pass. This is especially true if the boiler pres- sure is too high. A broken or improper type of radiator valve can also restrict the flow and cause water to back Steam Flooding - Part 2 By GeorGe Lanthier Figure1