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I think theres an issue with an install

I gave my niehbor some advise this spring when he got bids for a new gas boiler. 1: I asked him to have them install a drop header which he elected not to do and 2: run both dry returns down to meet the 28" drop then tie them together wet then into the boiler

The contractor instead left both dry returns tied together (as they already were) up high and tied them together about one foot above the boiler. I thought that this was the wrong way to do it. Will he have problems as a result of this? Is it acceptable to tie 2 dry returns together and only have about 1 foot of wet return.


  • Rod
    Rod Posts: 2,067
    Connecting Returns (Drips)

    Hi - The returns shouldn't be joined until they are well below the boiler's waterline level, otherwise they will cross feed, Here is a great video by Gerry Gill showing what happens when two different return pipes join above the waterline level. 


    In this case, the previous replaced boiler had a much higher waterline so originally the horizontal pipe (which was originally the wet return) has turned into a dry return as the new boiler has a much lower water line so that now the two returns join above the new boiler's waterline and cross feed.

    Gerry Gill is a very experienced Cleveland steam pro. His website  http://www.gwgillplumbingandheating.com/

    has a lot of good info on steam heating.

  • ctjomac
    ctjomac Member Posts: 52
    Thanks for the video link...

    Is it legal to tie the returns together ABOVE the water line?. Also, what symptons should I tell them to look for and will this create a dangerous situation for the owner or boiler?
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,787
    It's legal

    There's no law against stupidity, and it's safe, but they will have a devil of a time balancing their venting and getting their radiators to heat evenly.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • Rod
    Rod Posts: 2,067

    Hi -     It’s not an issue of legality nor is it dangerous.  It’s just with the return piping being configured this way, it can make the system much less efficient. How inefficient varies.   Having the returns cross feeding can stop or slow down the distribution of steam in the main being cross fed.  The symptoms of this happening  would  be cold  radiators and/or radiators which  take a long time to heat. If system is slow heating that means the boiler’s  burner is operating for a longer period of time until the thermostat setting is satisfied.   More burner “on” time  =  more fuel used.

     In a lot of cases returns, like we are discussing, did originally join below the boiler’s waterline as the older boilers that were used when the return piping was originally installed  had a much higher waterline. More modern boilers are much more compact with lower waterline levels and so the length of the returns need to be adjusted so that the junction of the returns will be below the modern boiler’s waterline level.

    Correcting the returns is usually a fairly simple fix either by extending the returns down  and then joining them below the boiler’s  waterline level or  by using what is known as “false waterline” configuration.  Extending the returns is usually the easiest of the two.

    - Rod
  • ctjomac
    ctjomac Member Posts: 52
    Thanks Again Rod,,,but how

    can a boiler intaller who has suppossedly been doing this for 20 years do that in good faith to himself let alone his customer. It's upsetting to me (a rookie) Its kinda sad to see my neighbor dish out that kind of money this past spring and wont realize it until the colder side of winter.
  • Rod
    Rod Posts: 2,067
    Boiler Installation

    The chances are that the installer who did your neighbor’s boiler is a good guy and was acting in good faith.  The problem is that he doesn’t seem to really understand steam heating.  Just because someone has been doing the same thing for 20 years doesn’t necessarily mean that they have been doing it “Right” for 20 years!  Unfortunately this situation is fairly common. Monitor this board during the coming heating season you’ll see some really “interesting” boiler installs.

    Steam Heating is really a Lost Art !
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,244
    If the boiler is in southern CT

    then that is pretty normal for installations. It is WRONG, but normal as everyone down there seems to do it that way.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
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