air in shower supply All aspects of plumbing questions and answers, help, tips and information

[stew-b]

we had a shower pump installed maybe 6 months ago and i did the rest of the installation myself,all works great except i have to bleed air from the hot water flow on the shower every few days,ie disconnect the shower head,lay pipe in bath and run on full hot with pump off for a couple of minutes while it coughs and splutters the air out.you can always here some air in it even after this though but the shower works properly again for a few days.if someone turns another tap on then the shower goes stone cold and it seems to work better when the central heating is off.
this is all getting really annoying now....here is a picture of the pump setup and feed,the cold feed i beleieve is tapped to the bottom of the cold water tank in the loft.there are maybe 3 metres of pipe in the loft and wall before a 90 degree turn immediatley at the valve,there are no 90degree bends in the loft,all pipes are as flat and smooth as i can get them so i dont think its a giant air bubble in the pipe.
can someone give me some help as to what the probelm is,i will need to get a plumber to do the work but like to know what the problem is and that im not getting shafted!
cheers
stew
link to pic-

http://i28.photobucket.com/albums/c202/ ... /003-1.jpg

[rosebery]

Your problem is where you are drawing off the water for the shower IMO. The pump does nothing for the pressure - that's created by the head between the top of the water in the CW storage tank in the roof and the top of the shower. The pump just increases the flow rate. So what it's doing dragging water through the pipes faster than if it wasn't there.

I this installation the pump is drawing air back down via the expansion pipe (vertical one going up into the roof) as well as water through the horizontal where you have the current tee piece.

You need to move the draw off point away from the horizontal to as close to the top of the tank as possible. Preferably you should also fit either a Surrey or York flange so that the water for the shower is separately drawn out of the cylinder from the supply to the taps. That will get rid of the air being drawn in problem and also mean that if someone runs a tap then the shower won't suddenly change temperature on you. These just fit in the top of the tank and replace the existing flange. You need Surrey for a female tank and York for a male tank.

You realy ought to tidy up the pushfit stuff as well. Pipes are gerenally far too long and should be trimmed to shorter lengths - thats cosmetic really but it is all under stress the way you have it.

You can do all this yourself in an hour or so with the correct tools.

Cheers

[stew-b]

cheers,i had suspected that after doing some reading on here,surrey flange seems to pop up alot :) its a little beyond my ability,how much should i expect a plumber to charge to do the work and supply the part?
many thanks.

[rosebery]

How long is a piece of string? You can pay (retail) anything from £20 to £ 50 for the flange and the labour is at whatever rate the plumber offers you.

I should get some quotes.

I'm not convinced it's beyond your ability either.

Cheers

[bobplum]

can i just ask
on the hot draw off past the first tee have you fitted something avalve or something
bob

[stew-b]

there are no valves or anything that im aware of.i think i have found a plumber who will fit a surrey flange for £120 all in,im pretty confident this will cure the problem.cheers for the advice :)

[rosebery]

Yes there is. On the RHS there is a lever arm ball valve in the hot feed between the tank and the pump. It allows you to shut off the water if the pump needs to be worked on. Cold should have one too IMO.

Cheers

[stew-b]

sorry yes it does have the 2 shut off valves,i though t he meant a one way non return valve or something like that.