Slow drain on new bath

[Dezzie1970]

Hi,
we have just renovated our old bathroom. It used to have a bath and sink all flowing in the same 40mm waste pipe along a straight run into the soil stack. 2.5m length
we have now introduced a separate shower. All the wastes flow into the same 40mm waste pipe, shower first then the bath then the sink. There was no option due to height restriction that the wastes could be attached to the soil individually. Joist space only.
The shower has a non return valve on it which prevents the tray filling when the bath empties, the sink as an air admittance trap on it which prevents the gargling, but the bath drains very slowly. Its a huge bath 255 litres approx. and takes about 10mins to drain. the pipework is all new to the bath. The run is approx. 3m through a few 90 degree bends.
I have checked the pipework for blockages and everything is clear. Granted the pipework is almost level whilst running through the joists but there was no other option.
At some points whilst the bath is draining it seems to stop! I cant figure it out why the water wont flow. Any help??????

 

[Nige F]

Hi,
but the bath drains very slowly. Its a huge bath 255 litres approx. and takes about 10mins to drain. the pipework is all new to the bath. h a few 90 degree bends.
??????

So 25 litres a minute - 90 degree bends , not 92.5 swept bends ? they will get worse as soap sludge builds up Would have been better if appliances could`ve gone into a 50mm. main run- But drilling for that would have compromised the joists

 

[Dezzie1970]

Cheers Nige,

swept bends would have been better. fortunately this is a spa bath so wont have the same amount of soap used in it as a normal bath or shower bath. I will of course on a regular basis clean the pipes out with a good quality pipe cleaner.
still cant understand why the flow when emptying seems to stop!
Dez

 

[footprints]

Is the soil pipe open vent blocked or air admitance valve on the soil stack stuck?

 

[Gasguru]

Granted the pipework is almost level whilst running through the joists but there was no other option.
At some points whilst the bath is draining it seems to stop! I cant figure it out why the water wont flow. Any help??????

Another bodge job that's not compliant with buildings regs. Do it properly.