Would like to know the best place on the wall behind the toilet for the pipe that will have the bum gun attached. which side of toilet? How high and how far away from toilet?

have you forgotten where your as@@@le is ?????

are you left or right handed?

As a rule 20cm from the floor and 20cm from the wc mid point either left or right what you prefer.

then pin the bum hook somewhere within reach!

If its a new wc sometimes easier to get a twin tap connector from the wall then one supply to gun and one to the cistrrn.

Normally you use single pipe and split to toilet and spray so on left side of toilet facing wall and about 3 inches high and far enough to left of toilet to allow access to flow controls/attachment of hose.

As Lopburi notes, you don't need to run separate plumbing for the "bum gun" just use a T-valve at the water outlet that refills the cistern:

Less PVC pipe and adaptors is always better, IMHO

If new, I'd do two runs. 13.5 1/2" PVC is not expensive. Even our village house has two ANA valves as a bum gun might fail, but we would still want the toilet to have water flow. ANA Valve and Sanwa and VRH have widely available valves. I've previously owned Karat, American Standard and Hafele bum guns. The VRH models worked best in my homes. One failure with an immediate free replacement. 12 year warranty on VRH, far longer than other brands and absolutely no run around a free replacement in Buriram. I looked at many VRH items in Bangkok near Central Bangna at the VRH showroom and at Hafele at the Sukhumvit Hafele showroom. I did not had a different replacement or refund experience with other brands of bum guns, even under the warranty period.

You normally put a shut off on the valve feeding the spray (to control pressure) so you just turn it off and still have flow to toilet.

You normally put a shut off on the valve feeding the spray (to control pressure) so you just turn it off and still have flow to toilet.

Absolutely correct. Some places have high water pressure and that is great for a fast refill of the cistern but on a bum gun, it can blow your lower o-ring all to buggery.

You normally put a shut off on the valve feeding the spray (to control pressure) so you just turn it off and still have flow to toilet.

Absolutely correct. Some places have high water pressure and that is great for a fast refill of the cistern but on a bum gun, it can blow your lower o-ring all to buggery.

Yep sure, but you still don't need two pipes for it - just install a ball valve on the "T" outlet that supplies the bum gun.