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Newbie boiler questions -- how often ro refill? What about after winter?

I've been in my house since '92 and only just discovered this site -- many thanks!  I've learned a lot that I wish I new in '92 but better late than never.

In Nov 2008 I got a new Peerless model 63/64 boiler for my house.  This replaces a boiler that was put in in late 1992 and was rotted away by end of 2008.

1. The guy who installed this unit, who is the "boiler expert" at my plumber (Nick at Mulder Plumbing in Teaneck, NJ) said that I should put water in as infrequently as possible, no more than every 3 weeks, if possible, because everytime you add water you are putting in oxygenated water which promotes rust.  Wha't your take on this advice?  If you agree, should I only take water out every 3 weeks, or should  do it weekly (which is what everyone else in the worlds seems to tell me).

BTW, Nick did not put in the previous boiler, another plumber did that (and that guy installed a boiler that was bigger than I needed and he used copper piping to boot, which I've learned is a no-no).

2.  After the heating season, Nick said I should not add any water, just leave it as is until the following winter, also on the grounds that to add water would be add oxygenated, rust producing water.  This conflicts with advice that several other people have given me who said that after the heating season ends you should FILL the boiler for the off season. What's your take?

Many thanks for this great site as well as for "We Got Steam Heat" which I just recently bought.


  • jim_72
    jim_72 Member Posts: 77
    edited February 2010

    David during the heating season you should blow down your low water cut out control once a week until the water runs clear and add water to replace what was drained. Then every 3 weeks open the boiler drain until that runs clear and replace water that was drained. At the end of the season you can leave the seasoned water in the boiler until the beginning of the next season, then you can drain it completely to remove sentiment and refill . But you MUST run your boiler soon after to extract the oxygen from the new water.That's It. Good Luck 
  • jpf321
    jpf321 Member Posts: 1,567
    jim's got it

    your boiler man sounds pretty good .. i would ask him other questions and compare his answers to the answers here .. yes, the answer is add water only when needed and when you add, boil it right away to drive off oxygen in the water .. and as jim said, drain a bit of water out of your LWCO (low water cut-off) if you have a float type (probe types don't give you the option) .. every now and again, you can also drain some water from the lowest valve on the boiler and try to get the mud out a bit .. but the most important rule of thumb is always boil after adding. 
    1-pipe Homeowner - Queens, NYC

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  • Adding Water to Your Boiler

    The boiling of the new water is a must!

    Filling the boiler- You quite often hear the advice of "fill the boiler for the off season" though most people don't know why.   If the boiler has a hot water coil and it is used in the off season for domestic hot water, you must fill the boiler so that the hot water coil in the boiler is submerged to make it efficient. Personally I use a electric water in the summer as it is cheaper to run and only use the boiler coil in the winter when the boiler is producing steam anyway and hot water is a by product.

    Also if you have a automatic water feeder, shut it and the water to it off during the summer. There is a danger with automatic water feeders that if the boiler piping develops a small leak they will constantly be adding fresh oxygenated water into the boiler and piping which can be very corrosive.

    - Rod
  • David07666
    David07666 Member Posts: 9
    Confused by one thing

    Many thanks to all who responded.

    I'm still a bit confused by one thing.  When Jm writes, "Then every 3 weeks open the boiler drain until that runs clear and replace water that was drained" -- do you mean a drain that different than using the low water cutoff drain?  Is there some sort of main drain at the bottom that I should be using?
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