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Water Spitting on 1 Rad Valve/ Valve Near Boiler / Sight Glass - Trouble Shooting for Steam Hammer?

Hi HH,

Still trying to discern why I've got a bad case of the steam hammer. I've repitched the four radiators with shims, I have supported some of the return piping so it's pitched back to the boiler. I have one radiator with a vent that spits water when boiler cycles (this is the hottest/2nd hottest of the four, see pic). Also, I noticed there is a valve close to the boiler that appears in bad shape (see pic). The sight glass is hazy (pic) and the pressure control appears low (pic and boiler is off). The rad farthest away from the boiler is the loudest and is warm at the bottom of the radiator.

My questions are:
1. Should I replace spitting valve on the radiator?
2. Should I replace the beat up valve that's nearest the boiler?
3. What is the site glass telling me with the haze?

Thank you in advance for your suggestions!

I will figure this out!


  • FredFred Posts: 8,281Member
    That vent near your boiler can't be working, in that condition and even if it were, it's way too small to effectively vent the main.
    The vent on that radiator is also probably not working. If you have water hammer, you have water pooled somewhere in the area of the hammer. It has to be found and fixed if you want the hammer to go away.
    When was the last time the boiler was serviced and cleaned? That pigtail that your gauge and Pressuretrol are mounted on doesn't look like it has been taken off and cleaned in years. The pigtail is probably clogged and the Pressuretrol probably can't see the system pressure.
    The mineral deposits in the sight glass; are you on a well? I think you should have the water quality adjusted and maybe a water treatment program that gets the mineral content back into a reasonable range. The boiler is likely caked with mineral deposits. I can't even see the water level in that sight glass.
  • neilcneilc Posts: 791Member
    a little bit of deferred maintenance there,
    where do you want to start?
    You know to blow down the low water cutoff, right?
    The boiler and main venting,
    the hazy sight glass is leaking, you could try snugging the bottom and top packing nuts there, loosen them slightly first to get them turning, a little penetrating oil at the threads may help.
    or the rubber snubbers may need replacing too, try snugging first.
    The Pressuretrol is set a bit high, dial it down to as low as it easily goes, inside that cover is a differential wheel, set it at 1.
    Under the Ptrol, your pigtail, should be checked that it's clear back to the boiler. The pigtail, that elbow and length of nipple,
    you need to be able to "Breath" thru all that, back to the boiler so you'll have to pull the Ptrol and gage off there.
    The main vent at the stairs, replace it with a Bigmouth mounted up high on a nipple or 2, high as you can get it.
    Is that your only main vent?
    Only one main in the basement?
    Post a picture of the boiler, from the floor to the ceiling, so we can see the piping above to the ceiling.
    And another where the return water ties back into the boiler.
    And then,
    yeah, replace the vent on the radiator, you don't want it spitting and leaking.
    the Holorans sell some good reading on steam.
    You want, We got Steam, for Christmas.
  • JUGHNEJUGHNE Posts: 6,536Member
    A sight glass that looks that crusty would be a sign that the pigtail might be plugged. Fooling both the pressure control and the gauge (which should not show anything anyway).

    And your main vent and whatever else Fred mentioned.
  • ethicalpaulethicalpaul Posts: 1,465Member
    > and the pressure control appears low

    No, it’s high. I would set it at the bottom (.5 psi cut-in). But stop turning the screw when the indicator bottoms out.

    If you feel up to it, there is another dial inside called “diff” that should be set to “1”

    Everything @Fred said sounds great too of course
    1 pipe Utica 112 in Cedar Grove, NJ, 1913 coal > oil > NG
  • jb802jb802 Posts: 6Member
    Can you see the linked album by the way? If not I will re attach to the post. Just click here.

    @Fred understood on the valves. I will replace. I'm on a well and will check water. We've been in the house since July but turned heat on November. There is a service slip (September - 2018- see pic) but I'm not sure what exactly was serviced or if anything was cleaned. There is one area where the pipes are connected and it bows, I've tried to prop it up. That is one source of the hammer.

    @neilc , Yes, deferred maintenance indeed, it's a can of worms! We didn't run the boiler, unfortunately, on inspection! Good advice on site glass and Pressuretrol, note it looks like the PSI went up a bit when the boiler fired. Not sure if that is significant. On the main vent, it's the only vent in the basement, yes. I guess that's the main? I tried to get the photo you were looking for from floor to ceiling with piping. I appreciate the reading suggestions.

    @JUGHNE roger that on the site glass and pigtail. Thank you for that.

  • jb802jb802 Posts: 6Member
    edited December 2018
    @ethicalpaul , I will check that and bottom it out. Thanks for that.
  • FredFred Posts: 8,281Member
    edited December 2018
    There are two risers off of the boiler header, each ties to a Main, so there should be another vent on the other main, either at the end of the main or where it returns to the boiler but before it drops to the floor.
    I also don't see an equalizer, on the end of the boiler header. That is a problem, both for equalizing the pressure so that water doesn't push out of the boiler and so that water can drop out of the steam, in the header before it gets sucked up into the mains.

    I see a drip on one of the mains. Is that main counter flow? Meaning, on that main, is the lowest point of the main at the boiler and the main rises as it moves away from the boiler? If that is the low point on that main, that may explain why there isn't another return. Water would return through the main to the Drip, near the boiler but there still should be a vent at the end of that main.
  • neilcneilc Posts: 791Member
    Actually the psi going up might be a good sign that the pigtail is open,
    does that gage drop all the way back down to zero, or the pin when the boiler is off?
    Do bottom out the setting on the Ptrol, lower pressure is better.

    I had not seen the boiler montague, it does show a few more items of need.

    agreeing with Fred ,
    your header stops short of an equalizer, and the plugged tee is right there for it. start oiling that plug.
    also no Hartford loop,
    it wouldn't take too much to redo the return side of that boiler, with equalizer, and rework the returns to a wet line and a proper Hartford loop return to the boiler.
    You need to figure out that other main, and how it's venting.
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