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42 OCTOBER 2015 | FUEL OIL NEWS | www.fueloilnews.com HVAC/ HYDRONICS I f you are a service manager you may, from time to time, ask yourself if all of the pumps your serviceman are replacing are in fact bad, or not. If you're a serviceman you may be asking yourself the same question. Many manufacturers wonder the same thing. Could you explain why you changed all of the pumps you have in the last year and were they in fact defective? OEMs tell me, and have for many years, that many were replaced for no reason at all, or at least the incorrect reason is stated on the warranty tag (sic). When they pumps arrive at the factory the only problems found are from faulty installation or incorrect service tech- niques. One of the OEMs favorite returns is a "blown pump seal." Most technicians have never really seen a blown seal. If you had, you would remember it! Oil everywhere! Many returned pumps that have nothing but loose plugs, are tagged "blown seal!" Try to remember this important fact. High speed burners have fans that are turning at 3,450 rpm, and sucking everything right into that burner housing including oil dripping off those loose plugs and fittings. The best test I have found to check for this is to take a piece of newspaper and pass it around the air gate. If it gets wet, something is loose out there besides you. So, we're going to back in time and dust off another Bruce & Bubba article. Thanks for asking for them. Our buddy Bubba of the now world famous B & B Burner Service, is having another mystical problem. What really mucks the thing up is that Bruce is away on his first vacation in five years and has left Bubba in charge. God help us! You know somebody really needs a vaca- tion bad when Bubba is left "holding the fort." Bubba has received a call from Mrs. DeMean, who is a little upset because first, Bruce is not around, and second because the new burner keeps going off all the time. Bubba was here a few days ago and found the unit off on safety and the pump needing a prime. Mrs. DeMean wants to know: "Why the hell did Bruce leave on vacation right after putting in my new boiler—didn't he know I could have a problem? All he really cares about is mak- ing the sale; I should have bought that gas boiler the plumber wanted to sell me. Do you have enough brains to fix this thing, young man?" "Gee, I think so Mrs. DeMean, I'll check everything over and see if I can find out what's wrong. I'll get to the bottom of this," replies Bubba. "You said that last week," says Mrs. DeMean. "You better fix it this time, or Bruce won't get that last payment, and I don't think you can fix it so my money is safe." Do you have any customers like this? Let's take a look at the job, Figure 1. It consists of a gravity feed tank in the basement, with an oil filter at the tank and at the burner (dual filtration, a B&B trademark). A new sleeved oil line and a combination filter/anti-syphon valve (oil safety valve) have also been installed at the tank. Both filters are "spin-on" types. All fittings are in flare or fitted pipe and there is no Teflon or Teflon based sealants anywhere in the system. Perfect job, right? So why the problems? First, there was plenty of new equipment put in including a new 3/8" oil line. Do these come pre-charged with oil? No, they're full of air. What about the new oil valves, filters and fittings that were put in? They also come with a free charge of air. To fix this problem the first thing to remember is that air is compressible. Water and fuel oil will not compress, air will. So when it appears that the oil flow seems to be all liquid, there may still be entrapped air. This is what "microbubbles" are all about. The problem gets even worse on a lift job because when you are trying to pull the oil to the burner, and you go over roughly 12" of vacuum the oil begins to separate and aerate. That's right, the pump begins to make air due to cavitation! One of the biggest problems we have in a forced hot water system is also proper air removal, so we should know how to fix this problem, right? Well, let's see. How do you get those air bubbles out? You purge or prime the system, right? In hot water systems you have system pressure to work with. In a gravity oil system your tool becomes the oil in the tank. Do you have any other tools you could use? Oh sure, you could use a hand pump, Microbubbles BY GEORGE LANTHIER* Figure 1