Condensate Treatment - Important?

Discussion in 'Boiler Forum' started by jadnashua, Jun 25, 2009.

  1. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,266
    Location:
    New England
    I live in a row of townhouses with a common, CI main drain. Nearly all, if not all, units have HE heating units that dump condensate into that drain. None of them have any pH neutralization treatment on them.

    How risky is this? And, if treatment is needed, is it better to try to do this for the building (in the order of 10 townhouses), or individually. Hassle is, trying to enforce it on even any one individual when you don't have access would be a problem.

    My concern is that over night, when the houses are the coldest, there would be little to no flushing of the drains by people flushing toilets, or other water flow that might dilute things. Probably, during the day, it may not be as big a problem. The interior drains are pvc, it only becomes CI when it gets to the main which runs between units and out the end.

    Thoughts?
  2. kingsotall

    kingsotall Plunger/TurdPuncher

    It falls under special wastes as the condensate is highly acidic. The IPC lists cast iron as an approved piping material as well as PVC. Only stipulation of concern is the condesate drain needs a trap if it is connected to sanitary sewer. Cannot daylight the condensate.
  3. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,266
    Location:
    New England
    Mine, and I think the others, pump it to the washing machine standpipe, so that wasn't the issue. I am (slightly) worried that when it is working the hardest, very early morning when nobody else is flushing toilets, 10 units in a short distance and dumping max condensate into the drain that doesn't get diluted.
  4. Dana

    Dana In the trades

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    Natural gas combustion condensate has a pH of about 5, acid, yes, but lower acidity than household vinegar (or even red wine, which runs in the range of pH 3.5-4.) Don't dump Drano or other highly alkaline substances directly into it then inhale the fumes, but don't worry about your drain plumbing. It can take it, even undiluted.
  5. flamefix

    flamefix New Member

    Messages:
    71
    Location:
    Exeter, England
    Here you can buy condensate nutralisers which are basically inline cartridges with limestone chippings in them. You can easily fit yourself.

    http://www.calmagltd.com/caldensate
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,266
    Location:
    New England
    Viessman sells them for their units...just not sure if it is cost effective or the consequences of not using it in my situation.
  7. flamefix

    flamefix New Member

    Messages:
    71
    Location:
    Exeter, England
    Well the talk here is again due to regulations that probably are meaningless in the US. But to explain, the water reaching the sewerage treatment plant is regulated to be a certain ph and if the ph increases or falls it breaks the regulations.
    There was discussion about future problems with large amounts of condensate discharge but I haven't heard anything recently.

    http://www.buildingtalk.com/news/unk/unk101.html

    Put it this way; it won't do any harm to nutralise it but it will cost you financially to do so. Your call.

    BTW
    As an installer I give the client the option, it's an easy retrofit anyway if it's not taken up initially. But each year when it comes round for annual service it's another item to earn from in replacing. So I'd be financially motivated to sell one, as well as environmentally motivated. But it is customer choice, there isn't any pressure.
  8. Runs with bison

    Runs with bison Member

    Messages:
    897
    Location:
    Midwest
    Carbonic acid is pretty mild at typical drain temps. That is what we are talking about. With plastic sewer lines I'm not at all concerned about it. Iron lines on the other hand were a massive PITA with ANY form of condensate...even those without large amounts of CO2 (AC condensate was a friggin' nightmare.) They corroded badly and eventually plugged all of the traps with iron oxide that had to be snaked and flushed out (several homes.)

    Clay lines at work were even worse, not because of carbonic acid but because they deteriorated after 40+ years and had to be completely replaced to get any flow.
  9. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,266
    Location:
    New England
    I'm in a row of townhouses. Internal drains are pvc, but they drain into a common CI main line that runs through between buildings. My concern was with the coldest part of the night, there's little toilet flushing or showers to dilute things, and with numerous units dumping into the drain, should we worry...still not convinced one way or the other, and then there's the required individual maintenance - there'd be no way to confirm anyone recharged the neutralizer unless we did something as a group, and then it wouldn't sense the individual systems dumping. A mess that we may need to address if the CI drain ever fails, I guess. Unless I can get some compelling evidence to push individual treatment and come up with some way to enforce its maintenance.
  10. flamefix

    flamefix New Member

    Messages:
    71
    Location:
    Exeter, England
    How much will the heating units be running at night? generally here but I don't know how cold it gets for you the heating isn't on over night or if on weather compensated it is on set back and then the heater will only come on if the set back temperature is reached. Of course that doesn't stop anyone running their heating 24/7.
    My point is how often will the units run at night and does it then pose as much of an issue because it is likely the greater use will be during periods when the occupants are up and about and using the sinks and toilets etc, perhaps?

    The other way is to arrange a great deal with a servicing company to service the heater units every 12 months and at the same time check and replace the individual nutraliser as part of the price. This way everyone benefits, the engineer gets a nice little contract and each owner gets a cheaper rate that they couldn't get individually. Plus the engineer can ensure he carries a stock of parts to provide a breakdown service knowing that all the units are similar if not the same and at the very least he'll know the units having serviced them. And you'll all get great after service, hopefully. That's if it works like that there.

    FWIW
  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,266
    Location:
    New England
    When it can get to -20F, even with setback, the heaters will run! Plus, not everyone uses setback thermostats. With radiant floor heat, the recovery rate isn't all that great, so I don't setback...did when it was forced air. Everyone owns their own heating system, and getting anyone to agree is near to impossible...so, likely nothing will happen until we need to replace the main line some day down the road (if ever). Cutting the line to check for wear isn't a good possibility, either. Running a camera might show something, but not sure if it would, or if the cost is worth the expense, either.
  12. flamefix

    flamefix New Member

    Messages:
    71
    Location:
    Exeter, England
    yup that's cold :)
    Well I guess you have answered you're own question then, worry about it if or when it happens, because even if you check and find a problem getting everyone to agree to do something about it is going to be near impossible.
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