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Fixing Up Old System

CantabHeat Member Posts: 33
edited February 2019 in Strictly Steam
First heating season for us in our 100 year old house with single pipe steam. Boiler is about 10 years old and is a 210k BTU/hr gas fired Burnham.

Early in the season house heated up but some radiators were cold and lots of noises. Had a local firm do a service and talked to a second. While these guys seemed to know about the boiler when trying to ask about the whole steam system didn’t go far. One basically told me “it’s very simple, fire makes steam, pipes get hot, heat comes out... nothing to go wrong really.” I wasn’t impressed. Found this site and read Dan’s book and learning a ton.

Things I’ve done so far:
- Replaced vents on cold radiators so now they get heat.

- System has 3 mains in the basement. Two had no vents anywhere in the main and one had a small one that was stuck closed. Mains were taking a long time to heat up. Installed Gorton #2s near the end of each main and now things heat up much faster. Required making a tap into two of the mains but managed to do it.

- System pressure was way too high and found pressuretrol was not functioning correctly. Pressures were going up to 5-6 psi at times. Dealt with clogged pigtail and adjusted control. Now cuts out at 2 psi (know I should look into adding a vaporstat but at least for now the pressures are more in check). Improved venting also helps keep pressure lower.

- Much of the basement main piping and near boiler piping had no insulation. Fixed that.

Issues still working through and need some advice:
- Near boiler piping seems a bit goofy relative to what Dan’s book says (see attached photo showing pipes sans insulation). Piping would appear to make steam ram into itself. Should I do something? Would consider repiping if it’s a big issue but that would need to be a summer project.

- Also seem to have an issue with some of the mains:

Main A runs along the east side of the house with 5 radiators coming off it on the 1st and 2nd floors. In the pic this is the left pipe. With the Gorton 2 it vents fast and quickly sends steam upstairs. This side works well. Radiators heat up fast with steady and smooth venting then they snap shut as expected. The main seems to be correctly sloped towards the end. The end of this main is also the start of the return piping where it drops down along the basement wall.

Main B runs down the middle of the basement. This is tapped into the right pipe in the pic. At the end of the basement the return drops down to join the pipe along the wall that started with Main A. The steam pipe then goes up into the wall where it makes a straight shot up to the 3rd floor for two radiators up there. This main seems flatter than A and heats slower. The radiators on the 3rd floor pant a lot while heating up (they blow air out, suck in, then blow out again).

Main C runs down the west side of the house and is the right pipe in the pic. It serves 6 radiators on the 1st and 2nd floor. This main seems somewhat flat towards the end of the run. The end of this main drops down to join the return along the wall right before that has one radiator tapped in that goes to the 2nd floor and a final radiator tapped in that goes up into the floor directly above. This radiator on the 1st floor takes a long time to heat up despite being right at the end of the main. Later in the cycle this end of the main has a lot of audible water sloshing sound and that water goes up into the 1st floor radiator... sometimes squirting out of the vent. This radiator also pants quite badly in and out.

Back at the boiler sight glass I observe that water level will steadily get lower until the low water cutoff shuts it off. Then the water quickly fills back in. It’s around this time that the water starts sloshing a lot at the end of Main C. It seems like the boiler is pushing the water backwards through the return and then back into the end of Main C and up into the radiator above. My thermometer gun shows that when this happens the return quickly heats up to 200F. The A dimension seems plenty big relative to Dan’s book (~40 inches).

1. Is the near boiler piping terrible and worth fixing or leave it be?
2. What would cause the water in the end of Main C and panting in Mains B and C? Concur that it appears to be backing up though the return? What should I do?
3. Main B and C are a bit flat and perhaps that’s causing the issues? If so how do I go about adjusting the pitch? Just adjusting the straps to the joists doesn’t seem like it would do it since the returns prop up the end of the mains. Is there a trick to changing the pitch?

Thanks for any advice. Have learned a ton so far and made some good progress but looking forward to getting the whole system purring.


  • Snowmelt
    Snowmelt Member Posts: 1,416
    your two take off are in the middle of the header , there supposed to be at the end you have two risers fighting against each other.
  • nicholas bonham-carter
    You will probably need more main venting, as a Gorton #2 is good for about 20 feet of 2 inch pipe.
    The water pushing into the returns is probably due to over pressure. Is there an accurate low pressure (0-3 psi) gauge on the boiler? The water level in the returns will rise 1.75 inches with every ounce of pressure.
    In addition to that, the two risers being on both side of the takeoffs is no doubt throwing a lot of water up into the mains.
    Is the water clean? If the boiler was never skimmed after installation, then the oily water makes for a unstable boil.
    Before putting the needed insulation on the pipes, use a level on each section of the mains to make sure you have the necessary slope al the way from boiler to return. Putting pieces of tape with arrows indicating the direction of flow is helpful. The pipes may have been allowed to sag during the installation of the boiler 10 years ago.
    The quote of the tech’s explanation of how steam works is very funny in a sad way. He must be likening it to running waterlines!—NBC
  • BobC
    BobC Member Posts: 5,479
    An easy way to find pipe sags is to run a taut string along the main - any sags will become visible.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • CantabHeat
    CantabHeat Member Posts: 33
    edited February 2019
    Thanks. Is there a secret to adjusting the level of the mains or is this a brute force exercise?

    Boiler water is clean. Used 8-way cleaner earlier in the season which pulled a lot of crud out but after removing that boiler water stays clear with the purple hue of the 8-way.

    Need to get a better pressure gauge that reads lower. Know I need the 0-30 for code. Seems logical that if pressure got too high it would push water back too far the wrong way. I suppose that means even more venting to avoid the boiler cutting off frequently? Mains heat fast now with the Gortons but perhaps more venting at the rads? Can one have too much venting?

    Thanks again for the advice. Very helpful.
    JUGHNE Member Posts: 11,075
    I use "Sammie Sidewinders" or the straight design,
    then 3/8" all thread rod with a clevis type "Auto Grip" pipe hanger.
    These let you adjust the pipe slope by turning the rod up to tighten the hanger. With a sag you can pull up the pipe a little at a time.
    Google those names I used, supplyhouse.com would have all of it.
  • Fred
    Fred Member Posts: 8,542
    Also, be aware that too much of that eight way will cause the boiler water to be turbulent and it sounds like what might be happening with the unstable water, as is obvious in the sight glass. When you get a break in the weather, let the boiler cool down, drain it flush it out once or twice and refill it. Don't add anything to the water, except one or two Steamaster tablets. Ignore the instructions on the bottle as that is misinformation and too much will also cause instability.

    What little I can see of the top of the boiler, it looks like a Burnham boiler. I also have a Burnham. They seem to be super sensitive to any oils that may be floating on the surface of the water. If you haven't skimmed the boiler, do that as well. Skimming very slowly to allow those oils to float off of the surface of the water and into a bucket or floor drain. Hopefully you have a skim port. If not, you can use the side tapping where the Pressure relief valve is. Post back and we can tell you how to configure that, using a Tee. It is not ideal but it works and is what I do with my Burnham.
  • Steamhead
    Steamhead Member Posts: 16,894
    Fix the near-boiler piping first. You're likely getting wet steam from that colliding header which will cause the symptoms you describe, even if there is technically enough pitch on the mains.

    I'd also enlarge the header one pipe size over spec. If the manual calls for a 2" header, I'd use 2-1/2" pipe.

    And, each main should have its own takeoff. This will make sure each main gets its share of the steam.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service