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New Hartford Loop and Venting

I'll be up front and admit that this work is mine. I replaced an existing oil boiler with this Slant-Fin Natural Gas Boiler. I've done hot water before, but this was my first steam. I relied heavily on the guys at the plumbing supply store, but I sure wish I had found this site when I first did the installation since you can see what their advice got me. (Although in my own defense, the previous install was much worse.)

So, the system generally works, but now I have some water hammer and radiators that aren't heating very well. The radiators are on the second and third floor, but the same riser, which is understandably the riser at the end of the main.

I have a multi-part plan:

- Re-pipe the near boiler piping with a Hartford loop that more closely matches the installation diagram. You can see the manufacturer's diagram and my own little diagram over the existing installation. Part of my wet return is copper and my plan is to continue the copper and join it to black pipe below the water line in the Hartford loop. The existing wet return was piped for a boiler with the return on the other side which is why I have the jog.

- Vent the main. Right now, there is no main venting. I have about 50' of 2 1/2" pipe with a volume of about 1.7 cf. By jpf321's handy tool, that means that I need 2 Gorton #1's for proper venting. This is a rental on the other side of the country, so I might add another Gorton #1 for redundancy.


- I used galvanized for all new piping because that's what the plumbing supply house guys said to do. I can't afford the time or expense of replacing it all, but I would use black pipe for all new piping that isn't copper. Considering the galvanized, I would also put a clean-out Y on the vent antler to protect them. Is that enough?

- My equalizer goes more than 2" below the water line. I know this makes my loop less effective, but do I really need to shorten it? If I'm shortening the equalizer anyway, should I use a Gifford Loop (like the one below) instead of a straight Hartford?

- Slant-Fin's diagram calls for a cross connection at the boiler return. Considering one leg isn't even used and I couldn't find one the first time, do I need to track one of these down or is a "T" sufficient?

Am I missing anything? Any input or advice that anyone would have would be very much appreciated.


  • Observations

    My first thought is since this is a rental unit it might be a good idea to get a steam pro involved.  In rental situation, an "incident" involving "do it yourself work" not to code, is a lawyer's dream.  Getting a pro involved also has the benefit of having someone local that can service the boiler and take care of it if an emergency arises.

    If you don't have them already I would suggest you get "The Steam Deal"

    All three are great books but "The Lost Art of Steam Heating: will be a big help to you as it explains piping in great detail.

    Your header piping while not too bad, could be improved, Having it drop down the face of the boiler and block the gauges etc isn't the best configuration. The header doesn't have to be just straight , it could have a 90 degree turn in it if this would help the configuration Just keep in mind that the header needs to have slope towards the equalizer so the condensate will drain .

    Main Vents- These are a must- "the more the merrier"

    Water Hammer-  This is hard to chase down until you get other item corrected. You need to insulate your steam pipes, especially the boiler piping and mains. This is very likely the source of your water hammer. You will also see a noticeable improvement in your system amd also probably on your fuel bill. The idea is to get the steam to the radiators and not have it condense in the mains. Here's a good link on insulation:

    Hartford Loop- The Hartford Loop is a safety feature. The idea is that if your returns spring a leak, all the water won't run out of the boiler and expose the crown plate and cause the boiler to explode.  That's why the connect of the return into the equalizer pipe is close to the waterline. As you have it now the Hartford Loop is useless as if the return broke, all the water in the boiler would run out.

    Gifford Loop-  As for the Gifford Loop, since this is a rental, I'd stick to the type every insurance inspector knows - The Hartford Loop!

    - Rod
  • PolycarpPolycarp Member Posts: 133
    RE: Observations

    Thanks so much for your response!

    My first thought is since this is a rental unit it might be a good idea to get a steam pro involved.

    I understand your point about finding a Pro, but unfortunately the quality of the "pros" available is one of the reasons that I am doing it myself.  I'm getting estimates of $1500-2000 for proposals to do it wrong.  Most of them aren't even proposing to add main vents.

    Your header piping while not too bad, could be improved, Having it drop

    down the face of the boiler and block the gauges etc isn't the best


    The gauges aren't actually blocked by the equalizer, they are offset on the boiler so that they are completely accessible.  The header is one part that I followed the manufacturer's specs to the "T."  It has the dimensions and lengths called out and it has the slope.  Is there any other concern except blocking the gauges?

    You need to insulate your steam pipes

    All the steam pipes in the basement are insulated.  I just used this picture since it showed everything more clearly.  The water hammer only happens when the tenants extend the cycle by turning off the radiators in the room with the thermostat.  (They have found that this will get the rear radiators to finally warm.)  My mangled Hartford Loop has a really long nipple joining the equalizer, which would be the primary candidate for the hammer.  But it joins so far below the water line, maybe not.  The lack of main venting would be another candidate.  So, hopefully with my plan to fix both, the water hammer problem will be solved.

    As for the Gifford Loop, since this is a rental, I'd stick to the type every insurance inspector knows - The Hartford Loop!

    That's a really good point.  Keeping things recognizable and straightforward probably has more benefit than whatever advantages the Gifford might provide. 

    Thanks again for your reply.
  • Thoughts

    Hi-  I'd have done the header piping a bit differently as I like to have the  piping out of the way. If it conforms to the manufacturer's instructions then it is fine as is. I would raise the point where the wet return enters the Hartford Loop so as to conform to the factory specs. Using a close nipple is also a good idea. 

    On the boiler piping don't worry about the cross, though I would use a plugged tee rather than an elbow at strategic positions on the boiler piping and wet return.  While you can install drains too, by removing the plugs you have a full port clean out and this really allows you to remove any accumulation that has formed in the piping. On the drain valves you may want to use a plug or if the drains have hose bibs a screw on cap as this makes things a bit more secure especially if there are children (or adults) that might play with the valves. I also think it's a good idea to remove the valve handles for the same reasons. (I put them together on a piece of wire and hang them on a nail close by)

    Gauges/Pressuretrol - In the picture it looks like these are mounted at an angle. These should be vertical. The older model pressuretrols were very sensitive to orientation and if they weren't completely level didn't operate properly.

    Automatic water feeder - I'd mount this higher than what you propose in the drawing,well above the boiler waterline.

    Venting-  Adding main vents will make a huge difference. With the mains you can't over vent.  With the radiators vent to the size of the radiator and this, combined with the good main venting, should balance things out much better.

    Code and safety-  While you might not be able to find a good steam man locally, I'm sure

    you can find a good burner man. As they have the instrumentation, I'd have them check the combustion for proper adjustment. This will make sure the combustion by products (carbon monoxide etc.) are correct and that the burner is adjusted for optimum economy.

    From a liability standpoint  I would have this done regularly (once a year minimum)

    I  don't know what your local codes are but I'd make sure you have the

    required and even extra smoke alarms and also alarms for carbon


    You may have already done this but from the picture your safety valve needs to be piped downward to about a foot off the floor where if it opens, no one will get scalded by the escaping steam. You might also want to make sure your boiler wiring is up to code as in the pictures I don't see a master shut off switch for the burner and most places require them. A burner man should be able to help you with this.

    - Rod
  • PolycarpPolycarp Member Posts: 133
    RE: Observations

    Thanks Rod,

    I seem to remember that the install specs specifically called for the gauges to be at an angle, but I will double-check this.

    Is there a reason to put the auto-feed above the water line?  Is it just an insurance policy against back-flow of boiler water into the potable water system?  Something else?

    I've got a couple of elbows in the wet return, so I think I'll install a drain on one and a plug on another.  That's a good suggestion.  Perhaps that's the reason for the cross?  to provide the same full-port access to the bottom of the boiler?  I think I might try to track one down just so that my install looks exactly like the manufacturer's spec.

    I have a dedicated cut-off switch for the boiler, it is just above and out of sight.  And I have a combo CO/smoke detector directly above the boiler.  That's a must in my mind if you have any kind of combustion source.  Although a yearly burner inspection is still in my maintenance schedule. 

    I've been mocking up a couple of vent configurations and will probably post them in the next couple of days.

    Thanks again for all of your input.
  • Auto Feeder

    No special reason for height on the auto feeder. I just think it gets it farther from the boiler water and also being higher I've found it easier to read.

    - Rod
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