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ericrw · Joined: 09 Nov 2007 Posts: 10 Location: leicester

After searching through 15 pages of previous questions I found one that was related to mine. The scruff was the moderator in respect of a query about " ahillsy" fitting a 3 bar pump which was proving to powerful. I'm wanting to fit a pump to my system. Because the pipes to the shower are reduced to 15mm from 22mm from both hot & cold tanks I've been told that because i've fitted a tower shower which includes 8 body jets all pipes should be 22mm but the pressure as it is. is poor but acceptable. To fit a 3 bar pump would I believe be excessive UNLESS it could be controlled. Thescruff, in his answer stated that you" could turn the valve on so far or even restrict the valve ". Is he referring to valves on the pump and how do you restrict the valve ?. The reason for considering a 3 bar pump is if problems occur because of 15mm pipes I would have to fit 22mm throughout which would prove to be expensive. Fitting a 2 bar pump is all the present system needs BUT if I had to upgrade !!!! Thanks in anticipation.

HSP · Joined: 22 Jul 2007 Posts: 92 Location: london

use a 3 bar pump and install a pressure redcing valve , one thats adjustable

dont forget pressure and flow are two different things! dont get caught out

ericrw · Joined: 09 Nov 2007 Posts: 10 Location: leicester

Thanks for your advice, at least I now have some idea what to do .

thescruff · Moderator Joined: 03 May 2003 Posts: 4616 Location: Bath

You will also need to consider the storage capacity, and the pipe sizes before the pump.

The cold feed to the cylinder would need to be a minimum 28mm for an 3bar pump and then feed the pump with 2 x 22mm.

A shower with body jets could be drawing a combined volume of 40-50 Ltrs/min, multiply that by the time in the shower say 10mins and you are looking to store 300Ltrs with a good mains recovery, and a 2-300 Ltrs hot water cylinder.

ericrw · Joined: 09 Nov 2007 Posts: 10 Location: leicester

The pipe sizes are correct for the supply to a 3 bar pump but from the pump to the shower the pipes are 15mm. Also the body jets work independently of the shower head. Does this resolve my problem ?

thescruff · Moderator Joined: 03 May 2003 Posts: 4616 Location: Bath

The supply pipes to the pump maybe correct but what size is the cold feed to the cylinder from the storage tank, if that is undersized then air will be drawn into the cylinder and cause problems.

The required flow rate/volume will be in the manufacturers specifications.

ericrw · Joined: 09 Nov 2007 Posts: 10 Location: leicester

The pipe from the cold water tank is 22mm but there is a tee junction which is 28mm to the hot water cylinder. Then from the tee piece it continues to what will be 22mm supply to the pump.

thescruff · Moderator Joined: 03 May 2003 Posts: 4616 Location: Bath

ericrw · Joined: 09 Nov 2007 Posts: 10 Location: leicester

Just been climbing in the loft and checking the airing cupboard. My lack of plumbing shows. The hot water cylinder is fed at it's bottom by a dedicated pipe from the coldwater tank in the loft. The tee piece I mentioned is on the hot water pipe to the shower system the other end of that pipe becomes the vent. Thanks for your patience.