plumber question

[dunr]

the water level in the bowl of my syphonic bog is at the correct level when i flush it, but in a few minutes the level goes down to half what it should be.
i have checked for water leakes and there are none.
can anyone help me with this please !

[maxine55]

proberley got a blocked drain

[dunr]

maxine
it can't be a blocked drain because because i flushed away an old motorbike yesterday - but thanks anyway.

[gasman]

When you look in the toilet pan can you see water trickling down from the back of the rim into the bowl ?

[dunr]

gasman
I answered you yesterday but it did not get on A.B.
water does not trickle down !
the problem has been intermittant but now it is permanant.
any other idea?.
regards.

[gasman]

OK if you have a vented soil pipe outside then it could well be blocked and this is causing a pull on the water and sucking water out. look up to the roof line at the large 110mm pipe and see if anything is blocking the vent. If you cannot see anything you may need to get up there and probe down to check.

[dunr]

Gasman
thanks for coming back, I will check the vent pipe as you suggest in a few days when i have been away, I'll report here and hope you are still around.
Many thanks.

[dunr]

gasman.
I could not check the vent pipe because too high for me.
I raised the manhole cover, which i think should have the same effect as clearing the vent pipe.
the problem was not improved.
any other thoughts?
regards.