Lavatory flushing oddness

[Edward]

We recently had a problem with a blocked drain just outside our lavatory window. Got the old drain rods out and rodded it and it seems fine. At least there's no more strange gurgling when the dishwasher evacuates.

Coincidentally (or not?) the adjacent lavatory has just exhibited a different action when flushing. It's a dual flush, and on the heavy duty cycle it flushes away fine until just before the end, when the bowl half fills and then very gradually (30-60seconds) subsides.

Anyone any ideas?

Thanks

Edward

[TheScullster]

"Edward" wrote

Edward

Sounds like you only partially cleared the blockage. Did you stick a hose down and make sure it ran clear at the next manhole? If not (or you don't have access to next manhole) try pushing a serious volume of water down and see if it backs up. It could be that you have just moved the partial block along the drain rather than clearing it.

Phil

[Bob Minchin]

Do you have some nominally horizontal (standard is 2.5 degree fall) pipe run from your pan to the vertical stack? If so I suspect that you have a partial obstruction in that section. I get a similar effect now and then and our loo has best part of a 3m run before it joins the stack. It either clears itself when the obstruction is great enough such that the water fills the bowl on the flush or sometimes it is a rodding job. Bob

[F]

We had exactly the same symptoms and I found the six feet deep inspection chamber in the drive full to within two inches of the top. A long pole and some careful(!) stirring got it to empty.

I can only imagine that there's a blockage between the toilet and where you previously rodded, or the contents of the previous blockage have been moved further downstream and are blocking again.