toliet siphon too strong

[stephen.r.forbes]

I have a strange problem that has just started on one of my toilets. It is located on the first floor of my house has it's own stand pipe. When the toilet is flushed, the siphon action is too strong. At the end of the flush, there is next to no water left in the trap in the bowl. This is soon followed by some air gurgling back into the bowl.

I've checked the access panel of the stand pipe and water is draining down it. It does not appear to be any faster than usual.

I don't think it is a blockage and there are no apparent water leaks.

My downstairs toilet is fine, but it uses it's own stand pipe. The drainage for the sink and bath end up in the same stand pipe as the "faulty" toilet and they are draining just as quickly as always.

Could this be an air leak in the pan connector?

Any help is appreciated.

~S~

[Chris Bacon]

Is it a real siphonic W.C.? If so, you may find that the "bomb" has moved.

[stephen.r.forbes]

The WC is a washdown type. And yes, soil pipe, not stand pipe.

Thanks

[Bob Mannix]

Perhaps the soil pipe is blocked with a bird's nest at the top?

[stephen.r.forbes]

The soil pipe has a slotted cap at the top to prevent birds entering and I haven't seen anything come and go, so I suspect it is clear. I'll get the ladders out to check though!

Thanks

[Bookworm]

Is there a long run of pipe going horizontally from the WC to the soil stack or does it go straight into the soil stack?

Have you changed anything?

[stephen.r.forbes]

There is about 1 m of pipe from the wc to the soil, nothing has been changed by me. The install is 8 years old and was put in by the builders of the house.

Cheers,

[Christian McArdle]

It does sound like a lack of venting, though.

Christian.

[Lobster]

Do - a blockage of the soil pipe between the cap at the top and the branch where the toilet meets it is the obvious cause (in your case I can't think of any other reason actually). See if you can drop a plumbline down it!

David

[Bookworm]

Lack of venting would mean that water would have a problem exiting the WC. Like upturning a full bottle of water. Glug-Glug.

More like induced siphonage.

[John]

It wouldn't be like a bottle at all as the toilet bowl is open to the air.

The piston of water going down the soil pipe is pulling down some of the water that should stay in the trap.

John

[Chris Bacon]

Perhaps it's a long partial blockage.

[Bookworm]

That is what I meant by 'induced syphonage'

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Chris Bacon saying something like:

Big shit.