Big mouth leaking

adasilva

So I recently put a new Big mouth vent on my main in addition to the one installed last season. I extended the branch so it was away from any water. So as I'm insulating my hot water piping the boiler kicks on and runs its normal cycle and suddenly the second big mouth vent starts puking water everywhere. Probably about a quarter of a cup of fluid came out. My question is is it a faulty vent I would be more apt to think so if it was the original one I purchased but this one is only about two to three weeks old. I'm not certain if my setup is incorrect the boiler runs near the end of the cycle about a pound and a quarter of pressure.

gfrbrookline

If to 90 is where your returns turn down to drain into the wet returns then your antler is pitched incorrectly and water is collecting under leaking Big Mouth. The antler needs to be turned 180 degrees so it can drain.

adasilva

@gfrbrookline I see exactly what you're referring to and why it would do it and it only makes sense. Is it possible that I ruined the vent?

Gsmith

The vent is not likely ruined. Pitch the piping to drain and give it a try

adasilva

@Gary Smith redid my antler and will see how it works from here on out!

DickC

Those aren't vents per se, they are thermostatic steam traps generally installed on the outlet side of a radiator on a two pipe system. They will let air escape until steam makes it to the bellows in the trap and then it close to allow steam to heat the radiator. As condensate collects in trap it will cool down the bellows, reopen and let condensate escape and close again when steam hits it again. Where did Big mouth vent come from? Not sure who recommended doing that but then again, when you think you've seen it all you haven't. Get a couple of Maid O Mist #1 straight Main Vents designed for this purpose. Not sure if you the tapping is 1/2" or 3/4", #1 is 3/4" male X 1/2" female, install with a couple of 8" or so nipples.

Jamie Hall

The Big Mouth wasn't leaking. It was releasing water which had made its way to it. The Big Mouth is a superb vent -- but it will not close against water; it's not intended to.

Fred

@DickC , They are produced by Barnes and Jones. They are modified traps designed to be used as Main Vents and they are excellent. I have several on my system and they work flawlessly.

adasilva

It was my piping configuration that caused the water build up. I have rectified the issue and have no more leakage

GW

side topic----@DickC are the MOM #1's good? They seem nicely priced yet i saw a comment here that they weren't built that well.

adasilva

@GW the venting capacity of the MOM #1 is mediocre at best when compared to the B&J big mouth vents. It would take 8 of them to equal the vent capacity of one B&J.....

GW

yes but is that apples and oranges? I don't think they serve the same purpose. i'm not a two pipe guy, I'm just a guppy.

GW

Jamie Hall said:

The Big Mouth wasn't leaking. It was releasing water which had made its way to it. The Big Mouth is a superb vent -- but it will not close against water; it's not intended to.

Jamie so the Big Mouth can be used on a one pipe as a vent? Just let the water drip on the floor?

GW

ahhh I see---- they can be installed vertically? It's fine if they drip a little? Good to know

adasilva

@GW I'm green as well but the MOM #1 is sold as a main vent but as I stated it would take 8 to release the same amount of air as one big mouth. From a cost comparison it would be about the same but labor wise it would be easier to install one vs eight? As for how they are built, take one of each and hold them in your hands that's all it will take.

adasilva

GW said:

ahhh I see---- they can be installed vertically? It's fine if they drip a little? Good to know

It won't drip if installed correctly, my pitch was wrong and it collected fluid.

GW

OK I didn't see the Big Mouth on the coveted Gerry Gill venting write-up so I just didn't know!

Jamie Hall

The BigMouth can be used as a main vent on any system. However, it is not intended to be used where it has to contend with water -- either backing up due to boiler pressure or, as it may have been in the case, where condensate can reach it.

It is, basically, a steam trap, and has no float.

ethicalpaul

> @GW said:
> ahhh I see---- they can be installed vertically? It's fine if they drip a little? Good to know

They don’t drip—the one in this thread was pitched wrong temporarily

gfrbrookline

@adasilva I am glad it worked out.

Koan

Agree with @Fred and @Jamie Hall
I have one functioning as the main vent on my 2 pipe vapor system and it works great, just not designed to close against water. It does have an integral O ring so they do not drip.

Koan

@DickC , I think the use of a vent that large on a radiator would actually vent a radiator too quickly. The "Big Mouth" traps are designed by Barnes and Jones to function as a main vent and follow the rule of venting mains quickly and radiators slowly. @adasilva can have high confidence in the choice of using this as a main vent.

adasilva

@Koan I think I was more concerned that I had ruined it by having the water get to it !

Koan

@adasilva I am pretty certain you caused no harm. I closed my return valves and ran the boiler to help clean the returns. I let it go a bit too long and had condensate come out of the BM trap. It still functions perfectly.