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annual boiler mud cleanout, and steam system maintenance / checking

bkc Member Posts: 37

This is related to discussion https://forum.heatinghelp.com/discussion/comment/1615558 (a two-pipe system with condensate pumps (one still broken) and boiler receiver tank)

Having been assigned the weekly task of blowing down our church's new boiler last fall I am educating myself on steam heat. Referring to the picture below, once a week I open the black ball valve until it runs clean (about 2.5 gallons), and then the yellow ball valve for about the same volume.

We're now discussing the 'annual maintenance' to be provided by our heating contractor. They finally sent me a list of items they will carry out. That list does not include draining from the bottom of the boiler (the red valve).

Is this something I can do, safely? I am not able to isolate the boiler from the building because some mains are missing valves (or I can't find them) . The contractor set the pressuretrol cut-off to 5 psi (something still to be discussed with them).

Should I fire the boiler, come up to temp, turn it off and then drain from the lowest point (red valve)? There is a floor drain in the boiler room, can I use a hose to run the water to the drain? Will it melt? How much water should I let out?

What other maintenance should I do? The contractor's checklist doesn't include some tasks, such as checking vents or F/T traps. Is checking a vent just a matter of finding them all and listening for air escaping as the system starts up? How can I check an F/T trap?

I have also found a number of short vertical pipes below mains that end in a cap. Are these supposed to be removed periodically to drain out rust/gunk (2nd photo), or would that only be done if there was a known problem?

Here's the contractor's checklist for their annual maintenance. Do you think there should there be more to it?
  • Visually inspect pilot and burner flames.
  • Visually inspect venting system for blockage, deterioration or leakage.
  • Visually inspect base insulation.
  • Check operation of low water cutoff, if used.
  • Check that boiler area is free and clear of combustibles materials
  • Check electrical connections
  • Check safety relief valves
  • Test safety controls
  • Inspect immediate flueways and clean as necessary
  • Remove and clean pilot assembly
  • Clean boiler heating surfaces
  • Clean burners
  • Perform combustion analysis and tune boiler as needed

Thanks, -Brad


  • Steamhead
    Steamhead Member Posts: 16,842
    Wow- if that boiler is "new" there's an awful lot of corrosion on that pipe in such a short time...................
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • mattmia2
    mattmia2 Member Posts: 9,660
    Might be a good idea to get a contract with someone who understands steam instead.
  • bkc
    bkc Member Posts: 37
    Hi, The boiler is new but the pipes are old. I believe this building started with coal fired 1-pipe in 1903
  • retiredguy
    retiredguy Member Posts: 905
    edited September 2020
    A lot of your questions depends upon the state in which you reside and the code that state follows for pressure vessel inspections and requirements.

    The first thing I would do is to contact the state boiler inspector and/or your insurance inspector, they are sometimes the same person, and ask for guidance and what is necessary and required.

    I don't know who soldered those copper lines in the 1st picture but they need more practice and instruction.

    I would at least remove the head from that MM #150 low water control, clean and flush the reservoir and inspect the float assembly and the switches under the inspection cover. When reinstalling the "head" as it is called install a new gasket coated with anti-sieze compound to assist with removal next inspection. A good service company will always do this for you during their inspection. Also the "pigtail" that the pressure controls should be mounted on need to be removed and cleaned annually. Operation of the pressure controls need to be done when the boiler is firing; just tripping the switch is not a test. Again check with the boiler inspector for his recommendations. As for the steam safety valves (relief valves are for water boilers), It depends on the boiler code in force in your area. The steam cut off pressure is usually determined by the engineer who designed the system. If this is a 1 pipe system, 5 psi is usually too high although I do not know your system so I can't give a definite answer. I always hated the contractors check list they are to impress the people who pay the bill. Contact a good company and the service tech will throw away the list and will do the job correctly the first time.

    When I was still working a good annual check-up could take all day and in some cases many days depending on the boiler and code requirements.

    Lastly, the combustion analysis should always be done on a hot boiler not on a cold start up just because the service company or customer is looking for the cheap job.
  • bkc
    bkc Member Posts: 37
    @retiredguy thanks for your suggestions! I will try to track down the boiler inspector. This is NY, we have an NY inspection number written on the boiler in marker.. No contact info though.

    This system doesn't have a pig-tail, but now that I look at it closely, it almost looks like steam can condense in the horizontal section. Interesting that all safety controls are fed through the same pipe.

  • mattmia2
    mattmia2 Member Posts: 9,660
    That is another way to do it without a pigtail. it traps water in that section of pipe. Those plugs should be removed and water flushed through it.
  • retiredguy
    retiredguy Member Posts: 905
    You are correct, your system does not have pig tails but instead has a trap type piping tree which I feel is a much better installation. Here in Pa. there is a certificate that must be hung in the boiler room that is issued by the inspection dept listing who they are and the dates of previous inspections. The inspectors are the "go to guys" .
  • bkc
    bkc Member Posts: 37
    This boiler's first (and most recent) inspection was Jan 2020, done by "The Hartford Steam Boiler Inspection and Insurance Co". I've checked out their website and found this checklist which has right at the top:

    Have a competent service firm disassemble
    the low water cutoff (LWCO) and make-up
    water feeding devices. All parts should be
    thoroughly cleaned and reconditioned as
    required, then tested before the boiler is put
    into regular service. While in service the
    LWCO should be tested once a week for steam
    boilers and once a month for hot water boilers.

    How about that..

    I also found this inspection checklist from NYC.

    I think we'd fail this:

    Bottom blow off valves are required to be connected to the lowest water space possible. The drain must be piped to a safe location. NYS Code 4-6.1

    (no piping on our drains)