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Thread: Boiler Condensate Line: 3 Questions (pic)...

  1. #1
    DIY Senior Member speede541's Avatar
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    Default Boiler Condensate Line: 3 Questions (pic)...

    I'm prepping the plumbing to receive the condensate line for a TriangleTube Prestige Solo 110 boiler we'll be having installed. I have three questions regarding draining the condensate line:

    (1) The plumber referenced installing a "drip catcher," for the condensate, as in not connecting the condensate line directly to whatever line I drain it into. I can't find any references to "drip catchers" on this site or elsewhere; can the condensate be plumbed directly into a waste line?

    (2) The plumber says my city requires a self priming trap for this installation, which he disagrees with due to the boiler being in constant use (DHW + heating, so it will see year-round use). I don't have any problem installing one, just curious if anybody can lend some background to this requirement (again, does it have to do with seasonal use of boilers?).

    (3) Here I'm looking for some advice: In the photo are two drain lines, a 2" copper laundry drain and a 3" CI that drains a low-flow toilet sink from a half-bath above. My plan currently is to install the 3x2 CI combi shown in the picture to the space where the cleanout is currently installed (moving the cleanout up), but I've still got to squeeze a trap in and obviously I can't notch the 4x6 PT stud. The condensate line will be routed along the wall on the right, approximately marked by the orange bubble level.

    What would you do to clean this up? Drain to the 2" copper, eliminating the extra trap? Place the CI trap along the wall? Something else entirely that I'm just not seeing? I'm trying to keep all the plumbing in the wall as much as possible, but don't see any way to avoid ducking around that 4x6 post on the right. I appreciate any suggestions!


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    In the Trades Tom Sawyer's Avatar
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    Using a san tee instead of the combo will shorten the length up but how are you planning on venting the trap? BTW the copper laundry drain is improper because you have an S trap going there.

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    Retired Defense Industry Engineer jadnashua's Avatar
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    Humm, the laundry stand pipe is vented right above the trap arm...is it really an S-trap?

    You could run the condensate line into the WM standpipe, but the (slightly) acidic condensate might be problematic in the long term with that copper there. Were you planning on a condensate pump? If so, the flexible tubing out of it would make it easy. If all gravity, then it gets messier (probably easier with a pump).
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

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    DIY Senior Member speede541's Avatar
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    Doh! Right, I can't use that CI combi at the end of a trap, what the heck was I thinking! Ok, so swap in a sani tee, and another roadblock, the vent for that 3" line is up in the ceiling, so I'd have a wet vent there and that won't fly (otherwise it'll suck my trap dry whenever I flush that toilet, right?). Dang.

    The laundry trap is done right, as far as I know: it's flowing into a sani-tee and Jim is correct, that's a dedicated vent rising up.

    The laundry trap itself is brass. Is brass OK with acidic condensate? If so... I believe I can switch out to ABS for the drop to the box, and switch out the copper sani-tee for a brass one, then add the self priming kit to ensure there's a constant supply of fresh water replenishing the trap and diluting the acidic condensate.

    I've got enough room to run a 3/4" line behind the 3" waste stack. Is 3/4" PVC adequate for a condensate line, and again my other question, is a direct connection to the laundry line OK, or do I need an air gap of some sort?

    Oh, and Jim, no plans for a condensate pump. I'd rather avoid it, if possible, but let's see how this goes...

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    In the Trades Tom Sawyer's Avatar
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    First off, Jad the trap to vent distance is not long enough there which is what makes it an S trap or what old timers like me used to call a 3/4 S trap, either way it's not legal but then, its's been there and working for a long time so unless an inspector raised a fuss I would leave it. As far as finding a vent for your trap, if allowed in your area you could always use an AAV

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    DIY Senior Member speede541's Avatar
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    Roger that. I see what you're saying about the trap to tee distance, but since it's a sani-tee doesn't that prevent a siphon condition from happening? In any event, it's been given a thumbs-up by the city, so...

    Just an aside, I should have mentioned that we used copper and CI on the drain lines because of a code requirement, otherwise we'd have plastic. But I don't know if a completely ABS laundry drain, including the trap, would be accepted. Guess I'd better ask. The laundry flows off the the left and enters the main 4" CI waste/vent stack, which immediately enters the slab and turns for a flat run towards the street; I hope acidic condensate water won't be a problem once it enters there. I've been reading up on condensate neutralizers and will definitely install one.

    It sounds as though I should focus my attention on entering at the laundry drain. I still have this question about an air gap (vs. an AAV?). I could make a 3/4" PVC connection to the laundry, come around the corner to the concrete wall, place a drip catcher there, and have the condensate line feed it from 2" away. I'd replace the 2" copper laundry line & trap with ABS, and install a heavier duty brass sani-tee. Should I still install a self-priming trap?


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    In the Trades Tom Sawyer's Avatar
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    Since the washer pumps water under pressure I would worry that it would pump some back up that condensate line.. To be legal, the condensate receptor would have to be large enough to handle the discharge from the washer should the drain plug up.

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    DIY Senior Member speede541's Avatar
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    So when you say "large enough," does that really mean "high enough?" If so, I'm almost certainly going to. be needing at a condensate pump.

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    Retired Defense Industry Engineer jadnashua's Avatar
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    If you go with a pump (probably the easiest), just run it into the WM standpipe using tubing.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

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    Engineer Furd's Avatar
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    Really, the pump is the easiest. Add marble chips to the sump to neutralize any acidity in the condensate and it won't adversely affect the drainage plumbing. In fact, many jurisdictions require an acid neutralizer on the condensate discharge from condensing (90+% AFUE) furnaces.

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    DIY Senior Member speede541's Avatar
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    Thanks fellas. The pump IS one more mechanical link in the chain that's prone to failing, but it looks like it'll be my fallback approach to tackling this. I appreciate all the help.

    Edit: OK, let me take one more shot at doing this pumpless. What if I do:
    - sani-tee out of the CI to an 1-1/2" ABS trap, similar to my originally plan
    - PVC or ABS around the wall as to a drip catch, as shown in my "drawing"
    - 1-1/2" re-vent from the trap to the copper W/D vent somewhere above the floor rim, probably up around the 6' level where I can come out of the wall and be above the stacked W/D?

    I have no fixtures on this floor connecting to the 3" CI line, so am I correct there is no flood rim to be concerned with so I can have a low drip catcher?

    And if this is an acceptable solution, is it acceptable to run 3/4" white PVC from the drip catcher and connect it directly to a 1-1/2" ABS trap buried in the wall? I can put in a wall-accessible cleanout to the trap, and / or put an access panel in front of it. It'll all be hidden behind the washer/dryer.
    Last edited by speede541; 03-06-2011 at 06:21 AM. Reason: on second thought...

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    DIY Senior Member speede541's Avatar
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    Bear with me, I haven't given up yet. I put together an illustration of my proposed solution from the previous post. Care to comment whether this is up to snuff before I run it by the inspector?

    Coming off the 3" CI, I've got a 2" combo to a 1-1/2" ABS sani-tee vent, then into a trap. A 1-1/2" copper vent (code requirement) rises to ceiling level and crosses over to the dedicated laundry vent. Connected directly to the trap will be the 1/2" PVC condensate line, fed by a drip catch further upstream near the boiler.

    I have just enough room to cram this all into the far right stud bay if I double the P-trap back on itself (3rd photo).

    This will all be happening at approximately the level shown (pretty low to the floor). The 3" CI line has no fixtures on this floor, and shoots an additional 2+ feet under the concrete before turning flat and running towards the street.

    I do plan to add a trap primer to abide by my inspector's wishes.

    Am I OK below the flood rim of the laundry box? Can I connect PVC directly to ABS (via the ProFlex fitting)?






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    DIY Junior Member GM Services's Avatar
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    Default Condensate Neutralizer

    You may like this apparatus better for removing the acidity from the water shed from your boiler - which will protect your expensive copper piping: We make these Condensate Neutralizers here in Michigan - designed to fit any size boiler and are rechargeable so you don't have to order more than one per boiler. Our website is www.condensate-neautralizer.com if you'd like more info.
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