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Boiler routine maintenance

Bigtim Member Posts: 9
I have a two year old boiler, Burnham Megasteam.  My old system required me to drain off a little water every week and then add some new water to the system. I believe this was to keep the low water cut off mechanism clean.  The new boiler has the probe style low water cut off.  It only needs to be cleaned once a year. I don't see any requirement to drain water weekly from this system.  Is that correct ?  What happens to the rust and gunk in the system?  The water I used to drain from the old system was like mud.  Does the boiler need to be drained and have the water replaced with a rust inhibitor every couple of years ?  Thanks for your input. 


  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,575
    rust inhibitor

    my theory with boiler water is--never give your boiler additives- like any good theory, there are exceptions, if you have well water, with excess chlorides, or other chemicals you may need some treatment. those of use on town water are usually safe.

    your boiler should have 2 more drains, 1 for the wet returns, and 2 for the boiler drain itself. a monthly draining of these 2 will prevent build up of gook inside the lower part of the boiler sections, and the return piping.--nbc
  • Bigtim
    Bigtim Member Posts: 9
    Found the drains

    I found the two drains, I am going to drain some water off of the lower one which I think is the boiler drain, it is on the same line as the boiler fill valve.  I not sure how much to drain, maybe about a gallon each time and then refill.  Thanks for the info. 
  • Boil the Water!

    Fresh water has excess oxygen which will contribute to boiler corrosion. If you add fresh water, bring it to a boil to drive the excess oxygen off! 
  • Bigtim
    Bigtim Member Posts: 9
    Boiler fill valve

    I add water using the boiler fill valve, which I assume almost everyone does. I don't know how to add water that I have boiled.  Does anyone else do this ?  Sorry, but this sounds a little strange.  Anyway,  H2O is H2O, whether boiled or not.  I'm a mechanical engineer but I paid a little bit of attention in Chem class.  I don't see how you reduce the oxygen by boiling. 
  • Unknown
    edited October 2009
    Excess Oxygen

    I know this defies high school chemistry ( I wondered the same things as you did) but it is  excessive oxygen that is problem in boiler water. Here's link with a brief description:


    You might want to check around as I'm sure there are better explanations on the internet. The Big guys with Big boilers worry about the "oxygen problem" a lot.

    On the home owner` level it can be a problem too. What I was saying is that when you add fresh tap water to your boiler, you should then turn the boiler on and bring it to the boil (make steam) This apparently drives off the excess oxygen.

    One of the main reasons for corrosion failure in boilers is that the boiler or one of boiler's pipes (usually the wet return) develops a leak. The danger is that with an automatic water feeder, the water feeder just keeps automatically adding fresh water (with excessive oxygen ) and this causes accelerated corrosion and premature boiler failure.  This is one of the big reasons that a lot of pros don't recommend automatic water feeders or suggest you use a feeder that counts how much water is added like the Hydrolevel VXT


    - Rod
  • Bigtim
    Bigtim Member Posts: 9
    Rod, you're correct

    Rod,  You are correct.  I quess a little bit of knowledge on my part is sometimes dangerous.  I read the link and also some other sites and indeed oxygen does dissolve into water.  The best example I read is the fizzing of a soda when you open it due to carbon dioxide dissolved into water.  The remedies sound too complicated for the homeowner based upon the recommendations in the link, perhaps it kind of takes care of itself when the boiler creates steam, drives off the excess oxygen and expels it out the system vents.  Anyway, thanks for you input, every bit of new insight helps us understand how things work. 

  • Steam is Weird!

    Hi Tim-  The fizzing soda analogy is a good one. I too questioned the excess oxygen when I first read about it. Steam is funny in that you run across things that defy common sense. It took me a long time to get past "pressurized thinking" and the fact that steam travels faster at low pressure than high. I envy you with your Megasteam. I think that's going to be my next boiler.

    - Rod
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