Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

No Drip legs allowed???

kcopp Member Posts: 3,990
Just saw this over on the main wall where an install had no drip tee/ leg @ the boiler. Apparently the City of NY no longer allows them on installs.... What the heck?  What is the reasoning... I figured that way a great way to protect the boiler/ appliance?



  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    I have two.

    I have two for my gas boiler. If a drip leg is that short nipple between the T and the cap screwed onto the end of the nipple, where the gas goes off the side of the T and into the boiler. Inside the boiler is another of those. It seems the boiler maker puts one inside the box, but the inspector wants to see it without opening the box, so the contractor put one right before as well.

    What I think is a drip leg is in the attached picture, if it attaches. Hey! It did. I think it is my first picture on the Wall.

    Start at the red expansion tank and go left. The tank slightly overlaps a 1" copper tube going up. It hits a Taco 007-IFC pumping down. The black pipe coming down from the ceiling is 1" gas pipe that comes down to a reducer to 3/4", goes through a gas valve, reduces to 1/2" goes left with a 90 degree elbow, goes down a little and through a union. Near the bottom is a T that goes straight down to a short nipple and a cap that plugs it. The other connection goes back to the right rear of the boiler. Basically, is the stuff below that T the drip leg?
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,216
    Yes Jean

    You have a drip leg. In MA they are required by code, the gas company in Springfield does not install them on their installations. Perhaps Tim could give us the reasons for not installing a drip leg. I know the reason for installing them is to collect debris and water before it reaches the gas valve. I am just at a loss as why not to install them.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Bob Harper
    Bob Harper Member Posts: 914
    gas vs steam drips

    I think you are confusing a "drip leg" installed on a city supplied steam heat system (Coned) vs. a "sediment trap" installed on gas utilization equipment per the fuel gas code. Both the IFGC and NFPA 54 require sediment traps on all gas utilization equipment except ranges, illuminating appliances, clothes dryers, and outdoor grills do Not require traps.

    Note that a "drip leg" in gas piping is located right at the point of entry into the building and is designed to capture liquids from 'wet' gas, thus they are not always required. Sediment traps are with the exceptions noted. I hear all the time about the local AHJ not requiring traps at the appliances. The AHJ can NOT minimize the code--he is there to ENFORCE the code---not legislate it. Every mfr I know requires a trap to protect their equipment. If you leave it out and there is an incident with damages where the trap could have prevented the loss, then you would be liable.

    Running traps or placing a tee horizontally with a 'trap' pointing down is not recognized by the codes. The gas MUST make a 90 degree turn into the appliance so that gravity can catch any condensate or debris.

    I know everyone calls traps on gas "drip legs" or "dirt legs" but you should use the correct lingo, which is used in the codes for a 'sediment trap' at the appliance.  

  • kcopp
    kcopp Member Posts: 3,990
    I stand corrected...

    not the 1st time. OK but still can't figure out why no sediment rap before going into the boiler. Seems like an invitation for a problem.
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666

    Should the "drip leg" -- sediment trap be opened every 10 years or so and cleaned out? Or is this being paranoid?
  • banjodog
    banjodog Member Posts: 6

    My old gas-fired boiler never had one for the 55 years it was in operation. This year, when it was replaced, a trap was installed.
  • Alan_13
    Alan_13 Member Posts: 10
    old style gas

    in NZ years ago, (and probably Europe), gas was manufactured, wasn't nat, it had a very high moisture content. Maybe installing trap legs is a tradition carried from these times.

     I've taken off plenty of trap legs to service/ replace equip, don't remember getting moisture or debris, but always put them back out of habit.
  • Al Corelli_2
    Al Corelli_2 Member Posts: 395
    I asked an inspector in NYC.

    He said too many "unauthorised" persons were removing the sediment traps and connecting other equipment.

    Al Corelli

    New York.
    Al Corelli, NY

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,839
    In 36 years...

    The ONLY thing I've ever seen in a natural gas drip leg is a little bit of cutting oil.

    I suspect that its roots come from the good ol' days when the installers of the gas mains used a hydro bore to drill the pipe to the house from the main in the street. After hydro boring, if the bore pipe held pressure, then it became the gas main service line going to the dweling. Obviously, there was water involved. And a real fear of that water getting into a gas valve/burner possibly causing problems.

    With the availability of CSST, I can understand the AHJ's reluctance to leaving ANY taps for the consumer to latch on to, thereby installing carbon monoxide generators (gas log fire places) and gas dryers, etc...

    Has ANYONE ever seen ANYTHING in a removed drip leg?

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • kcopp
    kcopp Member Posts: 3,990
    I have seen/removed..

    oil, a stray shaving or two and pipe dope. Just seemed odd that they well making them illegal.
  • Tim McElwain
    Tim McElwain Member Posts: 4,506
    Yes I have seen stuff

    in drip legs. more years ago than now. The old tin meters with leather diaphragms needed oil mixed with the gas to keep them from drying out so this would collect in the drip/sediment trap and cause a service call from time to time.

    The old gas mains here in the northeast have a lot of green nasty rust that is dormant until someone does some work on the main then it gets stirred up and may make it to the trap.

    I have on condo projects with all the gas pipe delivered and left on the ground seen sand in the traps after the pipe was installed, hmmm wonder how that happened.

    I must say however in the last ten years I have seen very little if anything in them. They used to be a good place to check gas pressures before we went to inlet and outlet taps on gas valves.

    On those away from the equipment in particular going to roof top equipment we used to fill them with methanol to keep from having freeze ups on piping on the roofs. This usually occurred when gas entered the building went through a gas meter and then exited the building to go to the roof. The changes in temperature would cause condensation in the pipes and then it would freeze.

    Funny question I got asked the other day, "Tim when you are real old and confined to the old folks home will you still be able to answer questions?" My answer was only time will tell. Old gas men never die we just slowly loose pressure"
  • John Mills_5
    John Mills_5 Member Posts: 935
    Here's one

    My young boss bought a new/used house and we changed the equipment this year. Someone tapped CSST into the drip leg of the furnace for the gas log. I piped in the new furnace and changed it. 
  • Tim McElwain
    Tim McElwain Member Posts: 4,506

    could you please e-mail me those photos at [email protected]


  • Bob Harper
    Bob Harper Member Posts: 914
    more trap erratta

    John M., do your local AHJs make you use a ground union on CSST connections? I know there is debate as to whether or not they should be allowed in lieu of a union but in a case like this where you aren't even within 6ft of the applinace, it is unecessary and just another major source of leaks, historically speaking.

    No bonding clamp on the steel pipe at the CSST connection.

    I hope that old ground key shutoff in the first pic was replaced.

    Did anyone calculate the pipe sizing? Test inlet pressure under full load? Many vented logs are rated 60mbh+ at 6wci inlet. This may be undersized/ low pressure.  

    I have removed all sorts of crap from traps: oils, water, metal shavings, rust, Teflon tape threads, rocks, copper sulphide black flakes, etc.. The bottom line is, the codes and all mfrs require them. If there is an Ooops! and the cause is determined to be foreign material that entered the valve vestibule and you removed or deliberately did not install a trap or failed to warn the owner a trap is required by code and mfr. then you are liable-period.
  • SWEI
    SWEI Member Posts: 7,356
    shutoff valves

    Are piped before the trap here.  Theory is you can shut off the supply & clean the trap without shutting off the main. 
  • kcopp
    kcopp Member Posts: 3,990
    On the bonding...

    clamp. It goes not at the CSST connection but far back where the black gas pipe enters the house.
  • Tim McElwain
    Tim McElwain Member Posts: 4,506
    From Gastite Systems

    Technical Bulletin TB2007-01-26-07 states:

    For attachment to the CSST gas piping system, a single bonding clamp must be attached to either a Gastite® brass fitting, a steel manifold or to any rigid pipe component. The corrugated stainless steel tubing portion of the gas piping system shall not be used as the point of attachment of the bonding conductor at any location along its length under any circumstance.
This discussion has been closed.