What kind of problems do they cause?
The toilet in my extension has an AAV. The vertical soil pipe is only about 3ft long and about 50cm from the manhole cover on a sewer pipe shared by 4 terraced buildings.
What kind of problems do they cause?
The toilet in my extension has an AAV. The vertical soil pipe is only about 3ft long and about 50cm from the manhole cover on a sewer pipe shared by 4 terraced buildings.
Okay, so finally got round to bodging some ducting from the stacks into the roof vents. Obviously this can't be permanent as the condensation will gather where the ducting sags, but hopefully will give me an indication over the next week or so whether this is the right move. If it is i'll have to get some lengths of solid piping and route it accordingly..
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I tend to support @opps viewpoint on this, that one possibility is poor waste pipe configuration. Toilet/bath/basin/shower should ideally be on their own pipes into the soil stack - but its surprising how often people tee basins/showers/baths into the same waste pipe for convenience.
What can then happen is emptying one item (baths in particular due to the volume of water ) creates suction which can pull the water out of one of the other traps - which then allows foul air out into the bathroom. The problem then mysteriously disappears when someone uses the item with the empty trap.
When I refitted my main bathroom, I had no choice but to have the bath and basin sharing a waste pipe into the soil stack - and I dealt with that by fitting HepVo valves in place of water traps. When you let the water out of our bath, you can actually hear the air being drawn down through the basin HepVo due to this suction, but because it is a dry one-way valve, foul air can't get out.
What can then happen is emptying one item (baths in particular due to the volume of water ) creates suction which can pull the water out of one of the other traps - which then allows foul air out into the bathroom. The problem then mysteriously disappears when someone uses the item with the empty trap.
When I refitted my main bathroom, I had no choice but to have the bath and basin sharing a waste pipe into the soil stack - and I dealt with that by fitting HepVo valves in place of water traps. When you let the water out of our bath, you can actually hear the air being drawn down through the basin HepVo due to this suction, but because it is a dry one-way valve, foul air can't get out.
Okay conclusions - I believe the smell in the downstairs loo is now gone, but the main bathroom remains. It did seemingly go for a while but is now definitely back - why I have no idea, but at least (I think) I've solved one of the two problems. So today I have removed the temp white ducting from the main bathroom stack (and emptied the gathered condensation), and refitted the AAV that was there before, so back to square one. The other stack though I have now routed solid pipe work, using an adjustable angle connector onto the top of the stack, and then solid pipework up to the black solid flexi pipe off the roof tile. I have nicked a second black solid flexi pipe from another roof vent and back to backed it using an offcut of soil pile, as this was the most straight forward thing to do given the route, and without spending a fortune on various solid pipe connectors. Weight is supported by an array of interconnected cable ties off a rafter. Hopefully this is okay..
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I diagnosed a problem like this with masking tape and cling film. I taped up the bath overflow then taped a square of cling film over the plug hole so that it was loose and I could tell if it inflated or was sucked flat. Each time the toilet was flushed the cling film went down, and after two flushes it was flat against the plug hole, so in my case the water in the bath trap was being sucked out
Brian
Brian