Bung in manhole mystery. - Soil pipe blocked up

[BobG]

Friday last, we noticed that the downstairs loo wasn't flushing too well - bowl was filling up perilously close to the lid then draining away slowly. Kitchen waste pipe drain was also full.

Yesterday morning my brother-in-law and I heaved all the covers off the 3 manholes in the garden - two were full of "you-know-what", and the third, the largest, which I think takes all the foul water from the houses up the road was clear and running fine.

We poked around unsuccessfully, then bucketed out the full manholes, and noticed that one of the blocked ones (which has an inlet, a branch channel and an outlet, all using crockery piping) had a crock bung of 5-6 inches in diameter with a thick outer rubber seal jammed in the outlet.

We looked at each other in absolute amazement! How on earth can our drains have been working for the last 20+ years with that in there ?

I could just reach it, provided my brother-in-law held me upside down by the ankles :;): It came out easily.

Er, I assume that we just keep the bung as a souvenir, and carry on regardless without it. It can't possibly be needed, can it ?

[carlbeardsmore]

It sounds like you have found a drop shaft. Have a look in the main site. It tells you all you need to know.

[danensis]

In the older Victorian drainage arrangements the last manhole before the sewer had a u bend in it (a bit like a toilet trap). This was to stop rats and smells getting up ftom the sewer. As you can't rod round a U bend, they had a straight pipe in line with the outlet pipe, and this was stoppered with a bung. Usually what happens is the bung falls out into the bottom of the U bend, and once the water level is up to the rodding eye the system worls as normal, using the rodding eye instead of the U bend as an outlet.

[BobG]

Carl, Dan,

Many thanks for your posts. I just couldn't resist going down there again, even though it was dark and rainy.

Ah haaaaaaa! Sure enough there is a hidden outlet that I didn't find the first time, it is basically a hole at the base of the channel, and it disappears down underneath the larger outlet that had the rat repellent bung in. It could well still be blocked up, as there is foul water up to the level of the larger outlet. So now our system is working only via the larger outlet, and I need to clear the U bend. I'm not sure what I can find to apply any pressure, but I expect I can improvise something - but it can wait until the weekend when I can at least see the brown stuff flying at me...

[flowjoe]

Danensis was spot on sounds like you have an interceptor trap on the outelt of the chamber.

They usually block due to silt, debris and grease, if it is shared by a couple of properties it will almost certainly be a 150mm main line, give it a good plunge and it should clear.

P.S if the properties pre-date Oct 1937 it a council sewer so let them have all the fun.

[BobG]

Great, with help from Joe, Carl and Dan, I've finally cleared
the manhole properly. I used an old broom stale, and attached a 3.25" diameter disk of 3/8" plywood with a 1.5" screw. I fashioned the disk by cutting the corners of a square and filing it roughly round. I drilled the stale and countersank the screw to make sure that the disk was really securely attached, since I didn't want it to come off in action.

I sloshed this up and down in the brown fluid in the hole below
the one that had the bung in, and then it made a gurgling noise and cleared. Phew!

I stuck the bung back in the upper hole, breathed a sigh of relief (it was safe to breathe again now), and replaced the manhole cover.

I have a photo of the drain and home-made clearing rod in my yahoo briefcase under "My Documents", "Manhole", I think you should be able to see it here by following this link...

http://uk.briefcase.yahoo.com/bjgrain

[mouldmaker]

What a fun way some people have of spending their weekends.

I'm left with a vision of you being lowered down by your ankles, Mission Impossible style, being careful not to touch the sides...

[Tony McC]

That's exactly how we taught the apprentices, Jon! Does them the power of good and helps build up their natural immunity!

[Tony McC]

Oh, and the photie is definitely an interceptor fitting.