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Surging, boiler just washed down

aircooled81aircooled81 Member Posts: 194
Water wanded the boiler, used the arm & hammer super soda, performed the skim. Not much at all but milky water came out then clear. Basically the water wand had knocked most of the stuff loose.
The sight glass is all over the place. While the boiler cycles, the water can climb over the sight glass, and drop to the fill level. While it's not doing that, it wanders up and down about 1" through the entire cycle.
I had lowered the pressures as low as they could go on the pressuretrol. Boiler cuts out at 2.6psig, cuts in at 1.1 psig. Now, it has a completely oversized vacuum condensate pump on the return. This is what I originally had attributed the flooding to. Now I'm not sure thats the only reason this puppy has a wandering water line.
I will due a litmus test next visit to check the ph, any other ideas to find out whats going on here?

I also have another kinda concern. every radiator on the loop has a control valve, 4 zones are multiple radiators on zone valves (like 2 to 4 radiators who's supply is closed when stat satisfies). I need to figure out an effective way to see of I'm getting severe vacuum on the supply side, or induced vacuum when a large zone opens when it holds a vacuum from being closed/off. Any thoughts here?


  • aircooled81aircooled81 Member Posts: 194
    I filmed the water and the guage, just cant figure out how to post video?
    Basically the fill is to about the 1/3rd sg. Then in operation it runs up to the 1/2 way mark (or there about). As the boiler gets up to pressure, or over 1 psig the water line moves to the 2/3 3/4 mark. Eventually the entire water line exceeds the sight glass view point then who knows how high the water line went.
    I tried draining the excess to get the line back down, no luck, it just comes back eventually.
    I pulled the union off the low water cut out feeder to see if it was leaking past, nope, shuts off well. Well astleast when the boiler was dry and cool. Not sure if this happens when everything heats up? Plastic cartridge in a MM model 51, so that i spose is a suspect. But i did close the make-up water valve while running the boiler too. Didn't stop the line from rising.

  • BobCBobC Member Posts: 5,101
    edited June 2016
    Post the vid to youtube and then post the link to the vid here.

    If you give ity a good skim that will tell the tale, if that surge comes back after awhile it may mean oils are down from the piping.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • aircooled81aircooled81 Member Posts: 194
    @Hatterasguy , thank you for the tip.
    I will do another flush and skim next visit. No particles came out on this skim.
    When I water wanded it, just gallons of brown water poured out for hours. When I cleaned the trap for the pressuretrols it was full of oily mud. Either the condensate pump sent some garbage back in, or now the castiron is releasing residual oil slowly. ?
    Any suggested additive and amount to clean-up high ph? White vinegar, whats the ratio per galons of water content to cut the high ph?

  • BobCBobC Member Posts: 5,101
    Make sure you know the PH before treating for high PH. Unltil you can test PH, just skim it.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • aircooled81aircooled81 Member Posts: 194
    So, I feel PH could be an issue, as also mud or oil in the water. I have been thinking, about how I am not happy with the near boiler piping. I have attached a picture of what the boiler piping looks like. Not to scale, but you'd get the point.
    Most predominant is the 2 risers are either both 2-1/2" or one is 2-1/2 and the other is 3. None the less, I bet the velocity through those suckers

    is over 50FPM. Compile that with the fact the equalizer is after the largest steam tapping, and I bet I'm throwing wet steam into the mains?
    The most common problem is water hammer for the first few minutes of cycling. This has apparently been an issue for over 50 years. The second issue is the water line surges over the sight glass eventually.
    When I first met this boiler, it was cycling at about 4 to 5 psig. I lowered it to 2.5 psig (lowest the darn pressuretrol would allow) and now notice the surging may be worse.
    I cleaned this boiler very well, so I will sample the water at next visit. I thought the oversized condensate pump was the cause, but now I think that's secondary to the issue at hand.

    Furthermore, I could reason that at the beginning of the cycle, the pressure is low. Actually a vacuum because traps down stream are leaking past (traps to be sorted out soon enough). As the boiler comes up to pressure, the water hammer starts to quiet down and eventually disapear. This may be because either radiators are satisfying, or the increase in pressure slows the velocity of the water carrying steam?

    any thoughts?
  • aircooled81aircooled81 Member Posts: 194
    @Hatterasguy , @BobC
    Do you fellas think my near boiler piping would explain the surging? And the water hammer at the begining of the cycle?
  • FredFred Member Posts: 8,418
    How long is the wet return(s) ? Have you flushed those out? They may be full of mud and some of it may be washing into the boiler.
  • aircooled81aircooled81 Member Posts: 194
    Good call @Fred ,
    I have plans to start checking out the boiler piping soon. Could be as long as 150' to the furthest radiator. 90 year old piping, some has been repaired due to leaks over the years I heard.
    I suspect some saggy or clogged returns. In the basement, all turns are made with elbows, no tees and plugs on any of the lines I have seen so far. No reason to think they put clean-outs in anywhere.
    I rebuilt 13 traps, I found 4 more leaking past but need more baskets. The condensate return to the pump is like 190*F!

    This boiler's gas train came with a Low and high fire valve, but they are both used because there's only 1 pressuretrol. I am thinking low firing the boiler after initial steam pressure is made (aprox 1.25psig) and seeing if it can simmer and maintain 1 to 2psig steam with just low fire. Might slow down the erratic water line too?
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