My kitchen sink is gurgling and backing up when large volumes of water are put down it. The washing machine drain is plumbed above the u-bend and when it drains it fills up back into the sink.
I've had dyno-rod over, disassembled the under-sink drainage and its all clear. The chap cleared the pipe from the small standpipe under the sink as far as he could go, with no problems i.e. no blocking there.
We tried the drain by putting a hose down the smal stand pipe and we could let it run for ages with no backing-up at all.
I noticed that when the sink is backed up, if I pull the flexible drain house out of the standpipe a little, air rushes out and the sink clears instantly. It seems to be some kind of air-lock.
What can I do, is it a drain venting problem? Could it be a problem with the soil stack, which I guess it where the drain is vented?
I was considering trying to lift the manhole cover to see if that was full, but unfortunately this is under the kitchen floor, as an extension has been built over it!! Could a blocked manhole cause this problem?
Eventually the sink does drain away, but it is very slow. I'm racking my brains to try to think what coud be causing the problem. We've been in the house for over two years with no problems.
I've had dyno-rod over, disassembled the under-sink drainage and its all clear. The chap cleared the pipe from the small standpipe under the sink as far as he could go, with no problems i.e. no blocking there.
We tried the drain by putting a hose down the smal stand pipe and we could let it run for ages with no backing-up at all.
I noticed that when the sink is backed up, if I pull the flexible drain house out of the standpipe a little, air rushes out and the sink clears instantly. It seems to be some kind of air-lock.
What can I do, is it a drain venting problem? Could it be a problem with the soil stack, which I guess it where the drain is vented?
I was considering trying to lift the manhole cover to see if that was full, but unfortunately this is under the kitchen floor, as an extension has been built over it!! Could a blocked manhole cause this problem?
Eventually the sink does drain away, but it is very slow. I'm racking my brains to try to think what coud be causing the problem. We've been in the house for over two years with no problems.