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Steam boiler acting up after the summer - Help!

Lev77 Member Posts: 55
Hi all,

Thanks for reading.

My house is heated by steam.
In preparation for the winter, we tested the boiler to check whether it's ready.

We turned up the temperature, and the boiler fired up.
After a couple of minutes, the pressure in the gauge started rising. Once it started rising, it just didn't stop. At some point the safety relief value was triggered and the boiler shut down.

Here are pictures of the boiler:

I tried to clean the boiler:

Emptied the boiler through the cleanout (#4 in the picture), then scraped as far up for any sediment. There was quite a bit - looks like it got hardened.

Then unscrewed the vial (#3), then the pressure sensor (#1) and then the pigtail pipe (#2).

I turned on the bottom valve right above the bucket in the picture. No water came out. So I shut it back off.
I let water run, and it came up through where the glass vial would be.
Then I put the vial back in there.

I let water run again, and it came up through where the pigtail pipe would screw in.

I cleaned up the pigtail pipe so water could go through, then put it back in and screwed the Honeywell pressure sensor back on top.

I filled the boiler with water up to 4/5s of the vial.
Then fired up the boiler.

It took the boiler a while to heat up the water, but then the pressure gauge again went up, crossed the 15PSI, then I shut off the boiler.
The pressure gauge kept on going up and crossed the 30PSI, as shown in the picture. The safety relief valve (located on the other side of the boiler) did not go off. But it's not normal (that I can remember) for the boiler to reach anywhere past 10PSI.

The water that comes out of the boiler looks clear to the naked eye, but when accumulated in the bucket there's visible dirt - it's not clear.

Any advice on bringing this boiler back to normal operation?
Would greatly appreciate specific technical advice. Thank you.


    EBEBRATT-Ed Member Posts: 15,517
    Sounds like you have issues you may need professional to resolve. You need to be careful with this as you don't want to lose the boiler

    although it seems you have made some good decisions and cleaned things up over pressurizing a boiler is not something to fool with.
    Did the boiler act like it was really pressurized to 30 psi when you opened the valve??

    It is possible the pressure gage is plugged which is giving you a false reading.

    If your not sure consult a professional
  • Lev77
    Lev77 Member Posts: 55
    When I opened the safety relief valve nothing came out. No sound of water and definitely no steam, even though the pressure gauge showed over 30PSI like in the picture.
  • BobC
    BobC Member Posts: 5,477
    Gauges sometimes lie, the original over pressurization may have damaged that gauge - try another one.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
    EBEBRATT-Ed Member Posts: 15,517
    Ok, sounds like a bad gauge for sure. Replace it.
    Most important:
    1. make sure safety valve is clean and installed correctly
    2. Make sure pigtail and piping to pressure control is clean and that pressure control is not plugged up
    3. Make sure gage glass and piping to low water cutoff is clean and that LWCO is clean and working

    Then you know it will be safe to operate.

    sounds like the bad gage is the culprit.

    It's a good tim e before the heating season to be sure everything is clean and working
  • Lev77
    Lev77 Member Posts: 55
    Thanks guys, appreciate the guidance.

    Is there a way to make sure that the top of the LWCO where the pigtail goes is adequately clean? I press in there and feels like there's like a rubber or plastic disc on a spring, and it seems to respond well.

    Other than that, trying to determine now if the pressure gauge is faulty or something is really clogging up the boiler inside (before I take apart the boiler to replace the gauge).

    Here's the other side of the boiler, with the safety relief valve.

    1. When I fill the boiler with water, the water does pass through the same pipes as the pressure would, seemingly without any difficulty. When I fill in water, the water vial level goes up as expected, and I can drain that water via the LWCO. Is it safe to assume that the pipe inside the boiler leading out to the safety relief valve is clear for pressure relief purposes, and that if there was pressure build up it would go up to the relief valve?

    2. If you look at the first boiler picture I posted, below the LWCO lever you can see a red valve. I'm not sure of the function of that valve.
    When I open that valve, nothing comes out. I don't remember if ever saw something come out of that valve when opened. Is that indicative of anything clogged up inside?

    After shutting off the boiler and letting it stand (with only the pilot on), the pressure gauge went back to 0 and has been at 0 since.

    If you feel like everything here sounds right other than the pressure gauge, I'll try another one (any special instructions for getting and installing a new pressure gauge?).

    Thanks again.
    HVACNUT Member Posts: 5,832
    edited September 2017
    The red handle valve is the boiler drain. If you're sure there's water in the boiler, and the valve is open, it is clogged.
    I would replace the valve even though the clog is probably in the pipe to the boiler.
    Have the new valve ready to go with tephlon tape on the threads, because once you clear the clog, you're gonna take a bath. Have a bucket there to catch water and put the new valve in on the fly. (It's going to be more than 5 gallons).

    Is that the cold water feed tee'd in where the relief valve is?
    The "real" steam guys should chime in on that one. Will steam pressure harm the auto feed? Water should be introduced below the boiler water line, and the relief valve should be as close to the boiler as possible.

    After you do what the other guys said, run the boiler, then flush/drain through the LWCO to make sure the burner circuit opens on low water.

    Close all the vents. Run the boiler to make sure the burner circuit opens on pressure.
    Open vents.
  • I am with @HVACNUT : What is this?!

    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
  • Fred
    Fred Member Posts: 8,542
    edited September 2017
    The pressure in that boiler should never get above 2 lbs. before the Honeywell Pressuretrol shuts the boiler down. Most of us don't allow the pressure to build past 12 ounces to 1 pound. The gauge may well be wrong but clearly the Pressuretrol isn't doing its job either. There is a tiny hole in the bottom of that Pressuretrol, if you take it off of the pigtail and turn it upside down, you will see it. Make sure that hole is not plugged. Also, if it were me, I'd replace:
    - both the gauge and the Pressuretrol
    - I'd move that Pressuretrol off of the LWCO. That opening in the top of the LWCO is problematic and always gets plugged with crud.
    - I'd put a 1/4" nipple and elbow on the opening where the gauge is and I'd put the pigtail on there, then tee off of the top of the pigtail, use two more nipples and two more elbows and mount the new gauge on one end and the new Pressuretrol on the other end.Put a 1/4" plug in the top of the LWCO where you removed the pigtail pipe.
    - I'd take the pressure Relief valve off and make sure that pipe is not clogged and I'd also replace that Pressure Relief valve.
    - While the boiler is down, replace that red handled drain valve as well. They will get clogged and/or leak.
    - Finally, if it were me, I'd buy a set of gaskets for the McDonnell Miller #67 LWCO and I'd take it apart and clean (scrap) all the build up that accumulates on the floor and side walls of that unit. They are suppose to be cleaned annually and replaced every ten years.What you felt when you push down through the hole on top is actually a float that rides on top of the water. It moved so it probably is free to float up and down but maybe only when you push on it. Buildup on the side walls may not allow it to float freely during normal operation.
    Having said all that, if you don't feel capable of doing these things, get a steam Pro in to do them for you.
    If you feel capable,When you replace the Pressuretrol, test it out to see if it cuts in and out like you set it to. If not, come back here and I can post a procedure on how to calibrate it. Set the Cut-In pressure to .5PSI and the Differential (the white wheel inside the unit, under the cover) to (1). That will give you a Cut out pressure of 1.5PSI and a cut in of .5PSI. (thereabouts) . You never, ever want the pressure to be where you considered normal. Keep it at no more than 2PSI max.

    One final note, Only fill the boiler up to 2/3's, Max 3/4's full. Filling it to 4/5's simply does not leave enough room above the water level to create an adequate "steam chest".
  • Lev77
    Lev77 Member Posts: 55
    edited September 2017
    Thank you all so much for the guidance.
    HVACNUT and New England SteamWorks, yes, in the last picture that I posted, that's the water feed in a tee with the safety relief valve. This has been like that since we bought the house a few years ago.
    I'm comfortable changing that if anyone thinks it makes sense and can advise where and or how to position these differently.
    I haven't used the autofeed of this furnace for a while, because a few years ago it worked non-stop and filled the pipes beyond the boiler with water. I've just been manually draining and filling the water as necessary. Since this is an old, non-self cleaning boiler, I have to visit it during the winter every few days anyway just to drain any sediment in the LWCO.
    If there are any thoughts on this, please let me know. I don't have much knowledge in steam works or this boiler beyond what I've shared above, and must admit I'm excited to start working on the boiler with the guidance here.

    Fred, thank you so much for your post. I'm going to get the parts and start doing all the work you've mentioned. A procedure would be great for testing - I'll get the work done first and come back here and post pictures for review.
  • Lev77
    Lev77 Member Posts: 55
    I'm back. Finally I was able to do most of the work.

    1. I replaced the safety relief valve. It appears that there's some dirt inside of the old one, making it hard for the valve to release pressure.

    2. I removed and thoroughly cleaned inside the LWCO. There was a lot of crap inside it. The float itself was full of crap, cleaned that as well. I replaced the gaskets. But I reassembled the ball valve without the Teflon seals.

    3. I removed and replaced the old pressure gauge. Looks like there was crap stuck in the back of it that I couldn't really remove.

    4. I removed and replaced the old pressuretrol, and repositioned it and the pressure gauge instead of the old pressure gauge using the pigtail.

    5. I also replaced the sight glass - the old one was breaking apart at the edges. I bought one which was longer than what I needed, so I cut it to size.

    6. I replaced the boiler drain valve with a ball valve. Why? not sure.

    7. I used blue sealant and tape over it for pretty much every connection.

    8. Today I came to test the boiler for the first time, but when I filled water, it was dripping down from the LWCO even though the ball valve was closed. I took it apart and realized I had forgotten to put in the Teflon seals. On the way, the new blowdown gasket also broke apart. So I ordered 3 more just in case.

    But I can say that the water that came out of the boiler had very little rust or mud color. It was relatively clean.

    Once I get the gasket I will reassemble the blowdown ball valve. I found the assembly instructions.
    At that point, would you say I'm ready to test the boiler again?
    Picture below. Thanks again for all the help!

  • Fred
    Fred Member Posts: 8,542
    edited October 2017
    Wow, you have a lot of pipe dope on those fittings.I hope you didn't get any on the inside of those pipes. That can clog the small orifices on the gauge and the Pressuretrol. Just a little tape on those fittings would have been fine and make it easier to take things apart to clean out the pigtail, once a year. I'd clean those off just for the sake of appearance. Also, something doesn't look quite right with the top of the LWCO vent pipe. It looks like is has popped out of the fitting. Did you put a compression ring on there? When you put the shut-off valve back on the LWCO, you may want to screw a 3 inch or so nipple into the bottom of it just to have a better flow into a bucket, without a lot of splatter.
    EDIT:Now that I think about it, I think that nut on the top of the LWCO vent pipe is a compression nut. Did you push the vent pipe in enough for the end of that nut to catch the vent pipe?
    New England SteamWorksLev77
    JUGHNE Member Posts: 11,060
    The "ball valve" for the boiler drain as discussed is the straight thru type with the 1/4 turn handle. A hose adaptor is added.
    This lets you open the valve and if clogged can be cleaned with a long screwdriver or such. Get a brass cap for when not in use.

    The new drain valve you have is somewhat of an improvement over original.
    Where does the water enter the boiler now.
  • Koan
    Koan Member Posts: 439
    I am concerned that you said the float in the LWCO and the LWCO itself was full of crap. If so, the float might be perforated and could fill with water and sink. I though I read that you cleaned out the float but did not replace it. I the float sinks, it will "think" the boiler is out of water and shut it off the boiler. It is possible all the build up of rust and scale in the LWCO was artificially keeping the failed float up.

    BTW I had this happen with my system with the same LWCO. Dueling failures!
  • Koan
    Koan Member Posts: 439
    here is a drawing and Part numbers to try to help

  • Lev77
    Lev77 Member Posts: 55
    Thanks all for commenting and for your patience. Takes me a while to work on this.

    @Koan, thanks, when I took apart the unit I drowned the float in water to see if any water goes in. No water went in. I'm assuming the float is still in usable condition.

    @JUGHNE, thanks, the water comes in from the other side of the boiler - check out my picture in post from September 16.

    @Fred thanks very much for the comment- as a good apprentice I disassembled everything, cleaned all the 1/4" pipes of the pipe dope and only used tape.

    After removing all the pipe dope and reassembling everything with tape, for the first time today I refilled the water in the boiler, and turned it on.

    Generally speaking, the boiler heated up and was sending steam up well. The pressure took a while to build up, but once it built up, the new pressuretrol shut off the boiler at 1.5 or so PSI, consistent with the pressure gauge.

    1. The vent pipe on top of the LWCO is leaking where the compression screw is. That screw doesn't appear to be in good condition. I inserted the pipe as far in as I could, but the inside of that screw is still full of crap buildup. I think I need to replace it.
    This is the whole assembly:
    Looks like I have to buy the whole assembly.

    2. Where the pigtail used to be, I put a plug. I tried to remove that plug because I used pipe dope. That plug is not coming out, and whatever I use is bruising/eating the metal (adjustable wrench, vice grips). I stopped before the head is more seriously damaged. I need to see how I can get that one out of there - probably I should use a nipple with cap instead, hopefully I can get this thing out. Now, when the pressure climbed up in the boiler, that plug leaked water.
    I wonder if there's a way to remove that plug from there more easily.

    3. The blowdown valve is dripping. I think I screwed up the PTFE seals. Also, the threads seem to be a bit worn out - I barely could get a plug screwed in there. I may have to replace the whole blowdown valve.

    Other than that everything seems to be working well!
    Any thoughts on the above would be great.
    Again thanks so much for the comments and help!
  • Fred
    Fred Member Posts: 8,542
    It looks much better.
    This Tube assembly is on ebay and is new and half the price.


    You may be able to take that compression nut to a local supply house and they may be able to match it for you.

    Is the valve leaking around the square gasket or is it dripping from the opening, like it isn't fully sealing? If from the opening, you can screw a nipple in the opening and then put a hose cap on the end of the nipple that you can unscrew to blow down the boiler. Replacing that valve is going to run you $80.00 to $100.00 bucks. You can try another set of PTFE seals.
    Also, if that plug on the top weren't leaking, I'd say leave it alone but if it's leaking, you need to get it out. I'm not sure what type of pipe dope you used but it definitely should not be eating the metal.
    Also, you don't need to put excessive pressure on any of those fittings when you tighten them up. Tighten snugly, test for a leak then tighten a little more if there is a leak but just enough to stop the leak.
  • New England SteamWorks
    New England SteamWorks Member Posts: 1,505
    Lev77 said:

    Generally speaking, the boiler heated up and was sending steam up well. The pressure took a while to build up, but once it built up, the new pressuretrol shut off the boiler at 1.5 or so PSI, consistent with the pressure gauge.

    Unless you purposely heated your house to 85 for test purposes, this time of year your boiler should go off on temperature, long before pressure.

    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    Eventually all those LWCO valves drip, and the cure is to install a secondary ball valve on a nipple, and blow down using that.
    This also gives a secondary chamber for the rust particles to settle into, instead of filling the float chamber.—NBC
  • Lev77
    Lev77 Member Posts: 55
    Thanks all.

    @New England SteamWorks - thanks, yes we did jack up the temperature to test the boiler.

    @nicholas bonham-carter - thank you, good idea.

    @Fred - thanks again, I bought that vent pipe set from eBay. The blow down valve is leaking from the opening. With the amount of crap in the water, during the winter we usually have to blow down the water every few days. Maybe adding another valve under is the way to go?

    The toughest problem right now is getting that plug out. It is not budging. The dope I used is the blue kind... nothing that should do anything to the metal or get this stuck I'd think. Maybe the plug itself is defective? The metal is getting eaten easily by the wrench / vice grips. At this point the head seems to me to be just bending or falling apart. If I want to save the LWCO I think I'll have to drill through that plug or use an extractor or something... which means I'll have to take the LWCO apart again. Who would've guessed.
  • Fred
    Fred Member Posts: 8,542
    @Lev77 , I agree, another ball valve will work. You'll just have to open both when you blow down or I guess you could leave the top one open all the time.I'm puzzled by the plug in the top. That should have been easy to remove.
  • Lev77
    Lev77 Member Posts: 55
    edited October 2017
    So as things turned out, I had to drill into that plug, and could only get it out in pieces. I might have damaged a very tiny bit of the thread of the LWCO, but now I easily screwed in a taped nipple. Now just waiting on the vent pipe and new float gasket, then I'll test to see if there are any leaks.

    I read somewhere that people have steam boiler cleaner capsules or something that they somehow get into the boiler to clean it.
    Is there something recommended that I could use to fight the buildup? What's the best way to get it into the boiler?
  • MilanD
    MilanD Member Posts: 1,160
    edited October 2017
    Rectorseal 8-way liquid, or Steamaster tablets will both condition water. Since you are already working on the boiler, you can try unplugging the bottom tapping opposite your return and wand-clean the boiler. Also, install access on a tapping above the water line for adding chemicals. You could remove the bushing where your controls tree is and install full 1" tee there, then add bushing into the horizontal of the tee and mount controls there. That will give you access for adding chemicals.

    This is how Gerry Gill does cleaning.
  • Fred
    Fred Member Posts: 8,542
    Don't try to remove that bushing in that boiler! You think getting that plug out of the LWCO was a challenge, mess with that bushing that's been there for years and you'll know never to mess with another one. I use 2 (just 2) Steamaster tablets, once a year in my boiler. I take put a Tee on my Pressure Relief valve (if it is mounted on the side of the boiler) and I crush the tablets dissolve in a cup or two of water and pour it into the boiler. If your PRV is top mounted, you can just use a funnel and pour it in. Do not use the number of tablets suggested on the Steamaster bottle. That is way to many and it will cause a very unstable water line/foaming.
  • Lev77
    Lev77 Member Posts: 55
    Thanks! I'll do that.
    I've received and installed the new vent pipe, refilled and started the boiler. Working as designed without leaks!

    Thanks again!

  • Fred
    Fred Member Posts: 8,542
    Looks Great!