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Summer Prep

My husband and I recently purchased a new old home with steam heat.  We've read through most of We Got Steam Heat and recently had a local boiler guy come out to change a radiator vent and tighten a few leaking fittings.  Per the book he seems to not be one of the bone heads and answered all of my loaded questions appropriately.  Then I asked what we should do with the boiler after heating season is over and he explained that they would recommend that we flood the boiler up to the main pressure release valve in order to slow down the corrosion process while its idle.  Is that typical practice?  We're new at all of this and I had never heard of that before but it did make sense.  Would love to hear comments on such a practice!


  • 1902Shingle
    1902Shingle Member Posts: 22
    Summer Prep???

    Nobody? :)
  • Patrick_North
    Patrick_North Member Posts: 249

    I'm not a pro, but until one comes around, I can offer this.

    Anytime you add water to a steam boiler it's ideal to bring things up to a boil to drive off oxygen dissolved in the water. Overfilling the boiler this way would only introduce more corrosive (oxygenated) water to the entirety of the boiler- above and below the normal water line.

    I think the proposal is not a good one.

    I've heard of folks doing the opposite- draining all water for the summer- but I believe this is generally considered unnecessary as "well used" boiler water has little in the way of dissolved oxygen.

    Good luck,

  • Paul Fredricks_3
    Paul Fredricks_3 Member Posts: 1,557
    not an expert

    But I have heard of wet storage, where the unit is completely filled for storage purposes. Yes, there is oxygen in the water which can corrode the boiler. Whether this matters or not, since the water is not constantly changed, I don't know.
  • Rod
    Rod Posts: 2,067
    Boiler Shutdown

    The purpose of flooding the boiler is to raise the water line away from

    its normal operating level as it is thought that the surface of the

    boiler water absorbs oxygen with then increases the potential for

    corrosion to the inside of the boiler at the waterline.

    Burnham Megasteam Manual recommends flooding the boiler. Quote:

    " With steam boilers, at end of season add sufficient water to fill boiler to top of water column and leave it that way until fall when water should be drained again to proper level. If at this time boiler water is dirty, drain water, flush out boiler, and refill with

    clean water to prescribed water level.

     Always keep the manual fuel supply valve shut offif the burner is shut down for an extended period of time."

    I have my boiler cleaned and the burner serviced at the end of the heating season as the heating pros usually aren't as busy then and therefore have more time to really check things over.  I drain flush and refill my boiler at that time and add Rhomar 903 http://www.rhomarwater.com/media/W-903.pdf 

    In the fall I drain and flush the boiler and refill it with "new" water. (Remember when adding any "new" water to always bring the "new" water to a boil to drive off the excess dissolved oxygen as this can be very corrosive)  I must admit though in the past several years I have skipped doing a full flooding and just added the 903 which seems to work very well.

    - Rod 
  • Owen
    Owen Member Posts: 147

    Your man is correct. Fill the thing to the top, fire it 'till just before steam and then close all the valves going in and coming out. In fall, drain down to normal level, open steam valves and fire to assure oxygen purge and you're ready to go.

    I tend seven boilers at a school district and do it completely different but this will work for you. It's called "Wet Lay-up". (I do one of the seven with this method.)
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