Gurgling noise from condense trap

[DIYheadache]

Hi All,

Can hear air/gurgling noises from condense trap on w/bosch junior 28i, when I empty the kitchen sink! Water drains away quite quickly and then I hear the noise from the boiler.

The condense drains in to the same pipe run as the kitchen sink, along a 3m run to the soil pipe.

1) Is this dangerous? - as it seems to be sucking in air via the boiler!

2) Would fitting an air admitance valve solve the problem? does this have to be fitted above the level of the sink?

The kitchen and boiler were installed just 3-years ago, the sink has an anti-vac bottle trap, could it just be a blockage in the pipe?

Many thanks

Pete

 

[JohnD]

can you describe how the condensate pipe joins the waste pipe? Is there a trap or a standpipe? Where?

Post some pics if you can //www.diynot.com/forums/viewtopic.php?t=129539

have a look at how your washing machine or dishwasher wastes are connected, are they done a similar way?

 

[DIYheadache]

Hi JohnD,

No photos to hand, but did this diagram. Hope this helps?

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• DIYheadache
• 3 Sep 2009
• 1

The condensate pipe joins straight to the 40mm waste pipe via a T-piece adaptop. The washing machine hose connects to a T-piece adaptor just below the sink,there's nothing else connected to the rest of the pipe.

Thanks

 

[bengasman]

As long as the boiler connection is between the boiler and the sink trap, you should be fine provided the trap has a 75 mm seal.
There must be no direct openings to the indoors air in the pipe that has the condensate connection to the boiler.

 

[JohnD]

As long as the boiler connection is between the boiler and the sink trap, you should be fine provided the trap has a 75 mm seal.
There must be no direct openings to the indoors air in the pipe that has the condensate connection to the boiler.

Sorry I don't follow that

In the diagram there is no trap shown in the condensate pipe

If the condensate pipe went into the sink waste upstream of the sink trap, then it would be open to the air in the kitchen.

 

[DIYheadache]

Thanks Ben,

The trap does have a 75mm seal, but I just read on the site below that it should only be used for basins. Should I change this for a standard P-trap?

http://www.bhl.co.uk/category/Marley_Monitor_AntiSyphon_Bottle_Trap

The condense is connected as below, but directly in to an internal vent pipe.

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• DIYheadache
• 3 Sep 2009
• 1

So I presume that this is correct?

Thanks

Pete

 

[JohnD]

can you draw how you plan to fit it?

BTW I find the bottle traps are much more prone to blockages and are disgusting to clean out. I much prefer the bends.

edited
I see your pic now. I still see no trap in the condensate.

 

[DIYheadache]

Hi JohnD

Is the condensate trap/syphon in the boiler? This is where I can hear the gurgling from.

http://www.worcester-bosch.co.uk/ca...nior--manufactured-march-2005---july-2008.pdf

Page 6, item 24.

Should there be an external trap before the condensate enters the waste pipe?

Thanks

Peter

 

[Agile]

There must be no direct openings to the indoors air in the pipe that has the condensate connection to the boiler.

Although that is technically correct as flue gases can come out if the boiler trap is empty, many of the installations I see do have an air connection and that is useful to balance the boiler trap and avoid other drains "pulling" on the boiler trap.

Tony

 

[bengasman]

If it is exactly as in the picture, it should be fine. From your description, it sounds as if siphoning sometimes empties the condensate trap. Not the end of the world, the main thing is that the seal in the basin trap keeps its integrity and no direct openings to the air.

 

[bengasman]

...many of the installations I see do have an air connection and that is useful to balance the boiler trap and avoid other drains "pulling" on the boiler trap.

Many of the installations I see are fed by 9 metres of 15 mm, that doesn't make it good.
An air inlet solves the siphoning and related noise problem, but some manufacturers insist on having the condensate run sealed from indoors air (I seem to remember WB do), where others like Viessmann allow an air inlet.
Personally, I don't see the problem of an airinlet, but if the M.I. state it has to be sealed, then that is what you have to do.

 

[JohnD]

these are more experienced answers than mine as I am just a householder. I have a Viessman which goes to a standpipe with a U-bend going into the soil stack, so it is air balanced. I had forgotten about the trap in the boiler

 

[bengasman]

The trap in the boiler has/can have 2 functions.
Waterseal that prevents poc getting into the indoors air.
Siphon/collection system that avoids slowly dripping of condensate and making the pipe less prone to freezing up.

If the boiler trap is empty for whatever reason, AND the condensate pipe is open to indoors air, there is a risk of poc getting in the room. Apparently some manufacturers are confident that the design of the boiler is such that the risk is negligible, others aren't.
The only true answer is in the M.I. of the particular boiler as they take precedence over everything else.

 

[DIYheadache]

Thank you to everyone for your replys.

So, to summerise.

The setup is fine, as in M.I, and safe so long as the water in the sink trap is not sucked out also. The bottle trap is fine but is likely to get blocked and is a pain to clean.

Many thanks

Peter