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Well McLain Oil Boiler "Making Air?"

Chris_102 Member Posts: 19
My uncle has an old Well mclain oil fired boiler. (I don't know how many sections or how old) I think he has about 4-5 heating zones & 1 for DHW. I have been there about 3 times over the past year to "update some purge setups" (which are on the returns, and correct) He also has a split loop for his 1st floor, which I also installed ball valves, so that i can correctly purge the 1st floor.

My question is that, he calls me like a month later and says that the baseboard heat in his M.B. sounds like a waterfall when it calls. Could this be a problem from the extansion tank? Maybe a circ.? I don't have a clue. I ask the question if the boiler could be "making air" because I've talked to another plumber about this problem and they said that they had a similar problem w/ a well mclain making air, and they installed a Spirovent and solved the problem. Now, before I get involved with something of that nature, i wanted to make sure that I haven't overlooked something, maybe a cheaper solution. By the way, I know it's air going trhough the system, because i've installed Taco Hy-vents on top of the boiler and on top of the air scoop and they pick up air almost evertime the boiler kicks on.

As, far as where circs. are located and the general piping layout of the boiler, it's a grey area right now. I am going to go and look at the job again tomorrow, so I can have more information for you guys if need be, Thanks again!



  • Timco
    Timco Member Posts: 3,040
    edited January 2010
    making air

    No boiler makes air, period. Air and gasses are released from the water during the heating process and need to be removed or they will find the best or easiest place to collect. Be sure to pump away from the expansion tank. If the tank was bad, you would have water dripping or shooting out of the relief valve. Buy 'Pumping Away' in the shop section of this site, and follow it's piping advise. NO air problems if you pump away and use a air removal devise of your choosing. Could also be some non-barrier type pipe on the system somewhere allowing air back in...

    Just a guy running some pipes.
  • Big Ed_4
    Big Ed_4 Member Posts: 2,690
    Air intake

    other ways air can enter the system is though a slab leak , is there any pipes running under a slab on the the job ? Another thing to look for ....is the extrol tank is piped up .They should be piped down and wet ... They last longer wet , but piped up they catch and release air from the system .. Air vents upstairs on the radiation can suck in air in the pressure is too low as well ...
    I have enough experience to know , that I dont know it all
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