New shower draining slowly

[oscarthecat91]

Nah, wouldn't buy that excuse at all. It shouldn't top out in the tray unless it's really shallow. What are they saying, if the waste starts to restrict even slightly from gunge/hair etc, then does it just run out the door?? The waste and run should be setup to drain properly without pooling to the top of the tray edge. If it can't then the tray should be changed to take a 90mm waste, raised higher, deeper tray used and then maximise the waste run size and fall. Proper design is what was needed.

To easily test whether the stack needs positive venting or not by removing the AAV(durgo) off the top and see if that then allows the tray to drain properly. If it does then the soil pipe needs an open vent and will need taken up and over the gutter.

I’m getting them back to look at it. The stack had an AAV on it when I bought the house by terminated at the first floor bathroom and only fed the toilet. The existing bathroom wasted go into a hopper connected to the guttering. As part of the work they extended the stack up to the attic level and fitted a new AAV.

There are velux windows in the roof so if it open vents would it pass building regs?

Worth noting all the current work has been signed off by local council building inspector and I have the certificate - so not sure how much real scrutiny they provided!

 

[Madrab]

Your LA BC wouldn't care if your shower isn't draining properly, they would only care that the stack and associated pipework is installed per the standards. Even then removing the AAV is only a quick test to see if back pressure is the issue. If it doesn't make any difference then another approach would need to be taken and that would probably be venting the waste run or increase it to 50mm.

As far as an open vented stack then the velux windows would need to be very low down on the roof to be affected. If they are standard height within the roof then there should be an issue.

 

[oscarthecat91]

Ok so I have had them back and they have checked for blockages etc and tested the shower again with AAV in situ. They still deem it to be performing fine.

So that I am not going mad I have taken two videos both with the shower on full chat, 1 with clean water and 1 with soap. Tray is not filling up with clean water. With soap it reduces the flow somewhat

Grateful if someone else could confirm whether this is acceptable or not as I’m beginning to think I’m going mad.

no soap -

Soap-

I haven’t paid yet.

 

[Madrab]

Looking at the vids, I wouldn't say you have much of an issue there. You have what looks like a very low profile tray (25mm?) quite a high output shower that coupled with a 70mm waste that's half way down the tray. A middle set waste like that is better with a rain shower overhead of it and set to the back wall side of the shower, not at the door side. I would probably have recommended a back corner waste too.

All that being said the outflow actually looks OK, maybe a little slow with the soap but that's just down to the size of the waste, take the centre catch trap out of the waste, does it flow a bit better?

 

[oscarthecat91]

Looking at the vids, I wouldn't say you have much of an issue there. You have what looks like a very low profile tray (25mm?) quite a high output shower that coupled with a 70mm waste that's half way down the tray. A middle set waste like that is better with a rain shower overhead of it and set to the back wall side of the shower, not at the door side. I would probably have recommended a back corner waste too.

All that being said the outflow actually looks OK, maybe a little slow with the soap but that's just down to the size of the waste, take the centre catch trap out of the waste, does it flow a bit better?

Ok, thanks for taking the time to watch the videos! I must have unrealistic expectations then - this is the first time I have had a 'proper shower' install (previous houses have been electric showers over baths) that someone sucking through a straw could effectively drain.

Ideally we would have had a rain head shower in the middle however with it being an attic room the ceiling slopes so there's not enough head height.

It does flow slightly better without the dip tube in however I don't want it getting clogged with hair.

 

[Madrab]

It does flow slightly better without the dip tube in

Yeah, it's flowing ok then. The way I picked it up from post #1 was that the water was overflowing all the edges of the tray at the trap and it isn't. It will run over the edge at the top parts of the fall built into the tray but with such a low profile, that's to be expected.

As long as the trap isn't being fully overwhealmed which it doesn't seem to be then it should be fine.