On 17/04/18 07:41, Harry Bloomfield wrote:
NY expressed precisely :
I can see that even if it's not the cause of the gurgling and back
flow into the bath, it's not a good idea to have water standing in the
pipe because it will (and does!) freeze in cold weather: several times
I've had to dismantle the pipework and pour boiling water down the
section that is normally horizontal/uphill, to encourage the plug of
ice to emerge.

I would look to modifying that, it does need to have a constant fall, to
avoid problems of freezing and blockage from dirt. It is also bound to
cause the gurgling and slow drainage.

1:100 to 1:60 for turds

bathwater can be steeper.


--
Theres a mighty big difference between good, sound reasons and reasons
that sound good.

Burton Hillis (William Vaughn, American columnist)