Toilet loosing trap seal

[Koogatubac]

Kind of gone mind blank lol

My sisters new build house

Downstairs close coupled toilet looses its trap seal, could it be down to siphonage or positive pressure in the soil stack or the toilet itself?

Soil stack i imagine runs up to the attic (9m in height)

Other appliances inc basins and a en suite shower doesnt show any signs such as smells etc also NO WATER MARKS AROUND PAN - so doesnt look like hairline crack in pan

It must have an amount of water in the pans trap as it doesnt give off smells
Any ideas?

 

[Dotty]

Definitely goes to the stack? I've had my my downstairs loo lose its water trap on the odd occasion, every time it's been a blockage in the manhole outside. The contractor who threw my house and all the surrounding ones up didn't size the drainage properly.

 

[Koogatubac]

From a installers point of view croppie i would imagine they would of took it to the stack, however you never know it could be a direct line to the drains.

Think if they get any trouble it maybe the best point of call to look at.

Hopefully wont get the experience what Tamz got with rodding the drains! Lol

 

[Koogatubac]

Cheers for the input croppie 🙂 shes not getting any smells and its not affecting the other appliances so thats a good point atm.

If the drain was blocked though, surely it would rise the pans water level wouldnt it? Or even affect the water flow of the other appliances, especially when they have about 4m of downhill to reach speed before they hit a 92* bend

 

[Billy Bob Bob]

i would be looking at a blockage

 

[Koogatubac]

It flushes fine aswell, as normal

 

[glenno1]

How quick does it lose it

 

[Koogatubac]

Within 2 hours it lowers its water level by a slight bit, however doesnt totally lose the water in the pan

 

[glenno1]

Can you put a pic up mebee it will help,is the water line lower than the bottom of the waste outlet

 

[chris watkins]

With such a high stack I would be looking at compression at the base.
Is the stack vented ??
If other fitting (try WC) are used above, is there any movement in the water of the trap?

 

[stevetheplumber]

compresion could be caused by partial blockage if this is something that has started after working ok for a while

 

[Billy Bob Bob]

would have thought if it was lack of a slow bend at the base of the stack,compression would show up by sucking the traps out of the bath,basin etc

 

[chris watkins]

would have thought if it was lack of a slow bend at the base of the stack,compression would show up by sucking the traps out of the bath,basin etc

Compression normally cause's positive pressure at trap but as trap falls some water is lost out of the seal. Effect can be increased if Durgo fitted & not open to atmosphere as this positive pressure can not be relived up the vent. (that's why we don't like em)

 

[Koogatubac]

Think they vent via a roof tile. Thing is out of 3 basins, 1 bath, 1 shower, 3 toilets, sink and w/m, its only the downstairs toilet which loses some of its trap seal :S might be a slight blockage or the drains havnt been sized right due to large amount of appliances

 

[chris watkins]

Size not a problem with that lot if 110mm
As I say, try flushing WC above & watch the ground floor one to see if trap water seal moves up & then down.