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Boiler Feed Tank question

We have a commercial Weil McLain boiler that serves 12 units and the auto feeder (vaiours ones installed by 3 different plumbers) never worked right and caused the boiler to flood or shut down. All were removed and the water is being fed manually to the boiler when the heat shuts off every few days or so. The plumber recommends a Hoffman Boiler Feed Tank and all necessary traps and controls would be included, warranty etc though it is very expensive. The hesitation is that we have very old pipes with lots of black sludge. We need to decide on the tank install soon. What I have read in Heating Help describes issues that arise with the tank and pump. Please let me know what you recommend so we can make a good decision. Thanks.

Comments

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,932
    edited January 23
    There are 2 different ways to wire up those tanks. One is a condensate return pump, the other is a boiler feed pump. Depending on the circumstance you may want to use one over the other. Based on your situation, it appears that you should use the primary LWCO to operate the feed pump. The primary LWCO should have a set of NC contacts and a set of NO contacts. By using the NO contacts to operate the feed pump, you essentially have a boiler feed pump. The pump only operates when the LWCO shuts the boiler down. In your case that happens every few days

    From your description, it appears that you had the pump wires up to the float switch in the tank that causes the condensation to get pumped back into the boiler regardless of the water level in the boiler. This is known as a condensate return pump.

    I corrected a similar problem by wiring the tank float switch to the water feed and wiring the NO contacts of the LWCO to the feed pump.

    Look at this for a better understanding https://heatinghelp.com/systems-help-center/returning-the-water-to-the-boiler-in-steam-heating-systems/. It is not always that easy.
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
    steam2pipe
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 13,111
    The boiler feed tank may fix the problem...........or cover up the problem.


    The thing you really need to know is where is your water going? You shouldn.t be using that much water to cause the boiler to shut down all the time. If you put a boiler feed tank in the boiler may run better because the water feed goes into the boiler feed tank that then feeds the boiler..........but a lot of makeup water is really bad for the boiler.


    If you have no tank now and the system worked at one time you need to fix all the leaks before investing in the feed tank.


    too much make up water will shorten the boilers life. It's like putting a band aid on something
    steam2pipeMad Dog_2
  • Long Beach Ed
    Long Beach Ed Member Posts: 1,053
    If the returns are clogged with block sludge, why not clean the system, repair the returns and have it operate without the tank?
    Mad Dog_2CLamb
  • dopey27177
    dopey27177 Member Posts: 885
    The boiler feed pump only covers up your problem.
    when the system is in full operation the feed. Pump will overflow.

    If you have wet return piping the piping most probably is loaded with muck, especially where the piping has to rise to the hartford loop.

    Clean and or replace all the wet return piping. This will need to be done even if you put a feed pump and tank in..


    Jake
    steam2pipeMad Dog_2Long Beach Ed
  • steam2pipe
    steam2pipe Member Posts: 59
    Thanks, everyone, for your comments. 2 questions. 1) How do you recommend cleaning the old pipes of the sludge? Also, good question about where is the water going. There is no leak - last time checked. 2) Do you think the sludge is preventing the condensate from returning and refilling the boiler with water so it gets low every few days?
  • Mad Dog_2
    Mad Dog_2 Member Posts: 3,885
    The Prime Minister is in the House!!!!!!  Hi Mr Myron.  Love your book.  Noel Murdough (RIP) was a HUGE admirer of yours and quoted you often.  Great to see you here!!   Matt Mad 🐕 Dog Sweeney 
    Long Beach Ed
  • Mad Dog_2
    Mad Dog_2 Member Posts: 3,885
    edited January 23
    That would be my first order of business: Where's the water goin? You have to staunch the flow of blood before you operate on the ❤ Heart.  As these other wise men, suggest, unless they are less than 25 years old, you can't go wrong changing those wet returns.  The days you could spend cleaning and flushing them would be better spent piping out new ones.  Mad 🐕 Dog 
    steam2pipe
  • Mad Dog_2
    Mad Dog_2 Member Posts: 3,885
    edited January 23
    The mud and sludge could definitely be impeding the condensate return, but that condensate would be backing up at the first higher point of exit and either burping up condensate and/or causing great water hammer.  On A tight, properly working system,, you should be able to shut the make up water and NOT have to add water for weeks or months.   You have leaks to find and fix first, sir.  Mad Dog 🐕 
    steam2pipe
  • Mad Dog_2
    Mad Dog_2 Member Posts: 3,885
    New, flushed and maintained wet returns could last 60-80 yrs easily, so its a very sound investment in the building and the future. Mad 🐕 Dog 
    Long Beach Edsteam2pipe
  • steam2pipe
    steam2pipe Member Posts: 59
    Thank you all so much!
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 13,111
    @steam2pipe

    If the boiler runs out of water............you have a leak. It may be leaking steam somewhere that evaporates and does not show. Could be a bunch of small leaks at valve packings or air vents etc.
    Mad Dog_2
  • Mad Dog_2
    Mad Dog_2 Member Posts: 3,885
    Exactly Ed.  Dry steam leaks ARE ROUGH to find and eliminate. Mad Dog