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10 PSI versus Maid-O'-Mist

Binnacle Member Posts: 126
I'm considering a high-pressure blowdown this spring of the 52-year-old Weil McLain E-9 that came with the house. Idea is to clean out much of the junk accumulated at the bottom of the vessel. Is certain it has never been done before.

I would prefer to flush it out with a wand, but along with several other errors whoever installed it ran the Hartford loop piping directly in front of the skim port. So unless I want to dismantle this piping (which I don't), wand cleaning through the skim-port appears improbable.

In addition the boiler has been successfully cleaned with TSP and is running with 80 ppm phosphate from TSP-as-an-additive, has very clean water and dry steam, and so I have no compelling reason to risk problems by opening the ancient skim-port-plug.

The same said installers of course did not install a king-valve.

I haven't been able to find maximum pressure information for Maid-O'-Mist Jacobus vents, so I'm wondering if anyone can comment on whether the assortment of new Jacobus vents are likely to be damaged by the 10 PSI generally suggested for high-pressure cleaning blowdowns.

Perhaps worth mentioning that the system was running at 4 psi every cycle with the old Pressuretrol set for 2-in 4-out when I first arrived. However the new vents were not installed until after the pressure was reduced.

Also have one each of a Gorton #2 and Hoffman 75 main vent, and one Gorton #4 radiator vent installed. And a Matco-Norca AVA-125 that I would enjoy putting out of it's misery.

I suppose I could close all the radiator valves.

Another idea is to take a risk and remove the entire cover plate that hosts the skim-port and then clean with a wand. This might not be so risky as it sounds because all the bolts have been replaced recently. Probably the gasket failed and it started leaking so it was necessary maintenance. Touching it again seems far less scary than if the bolts were original--but I could be wrong about that. No experience in this area.



  • ChrisJ
    ChrisJ Member Posts: 15,784
    edited March 2014

    It's a royal pain, but I would remove all vents and install 1/8" plugs at least on the radiators and preferably plug the main vent holes as well.

    I doubt 10PSI is good for any vent and I have a feeling they won't seal very well above 2 or 3 psi.

    Personally, I find the wand cleans better than a high pressure blowdown.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Steamhead
    Steamhead Member Posts: 16,901

    don't put that much pressure on the vents.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • Binnacle
    Binnacle Member Posts: 126

    Yeah, I figured it was not a good idea.

    Just had a thought, I wonder if it's possible to construct a flexible scope-like wand.  A bit like the scopes plumbers use to clear drain pipes, with a little camera on the end.  Except this would have a water-nozzle for washing crud out of the bottom of the boiler.  Would probably be possible to run it in through the obstructed skim-port or through the relief valve port.  Maybe it could be driven off the small pressure-washer I own.
  • Binnacle
    Binnacle Member Posts: 126
    cheap Borescope

    Found this:


    May just need this and a pressure hose that can be articulated somehow from one end.
  • Binnacle
    Binnacle Member Posts: 126
    3 PSI

    More I think about it the less I like the idea of touching the cover-plate or skim-port.

    Don't want to go around swapping every vent for a plug.

    So I might run a 3 PSI blowdown instead of a 10 PSI blowdown.

    Even though it might not do the best job of clearing away sediment, it should give me an idea of how much sediment actually remains after the six drainings and TSP cleaning this season.  Last time the boiler was drained the water had no sediment at all.

    May be at that "good enough" point where the risk-reward equation tilts against further fiddling.
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,322
    if you clean it too well

    after all this time you may expose leaks you never knew you had. Make sure if you clean it well it is on a day before a warm spell.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726