Installed a shower + low HW pressure + CW from mains

[Wannabe Plumber]

Hello,

This site has helped me loads over the last few weeks to assist in the installation of a cheap and cheerful power shower (1.5 bar required 3.0 max) and to correct the odd leaking stop cock and rad valve.

I just need a few questions answering before I go any further:

The cold water is fine as I have tapped off the 15mm mains cold that runs under the hot water tank.

I have a gravity fed system. Large Black Tank (in bathroom top level approx. 1.25 m above shower head) feeds into HW tank. Problem is the HW pressure, which I have taken from the tanks 22mm pipe and branched to a 15mm, which then feeds into my mixer shower.

Can I install a single pump to increase the pressure of the HW? and if so, where is the best position for the pump: Between the 22mm/15mm pipe and the mixer?

Also, one of the mixer connectors will not stop dripping it's only a small drip but I've had it off re-PTFE'd it three times now and it just wont stop dripping. It's a pressure connection, with olive to plastic 15mm pipe (which has the additional strengthening inserts in the end). Any suggestions?

Many thanks in advance.

P.S. If you need pictures or further description of system, tank, shower, etc. I'll be more than welcome to supply them.

 

[Wannabe Plumber]

I've edited the text as lots of views on the thread but no answers.

Is it ok? I've read the 'Read this before you post...' thread. I've tried to make it as detailed as possible

 

[Paul Barker]

You really ned a balanced supply to the shower. In your case you need at least 1.5 bar if you have read manufacturers instructions (MI) correctly.

If you were to pump the hot as you suggest it might work, but I would suggest hat you pump the hot and a new cold which you take from the tank in the bathroom. Buy a 15mm tank connector, saw a hole in the tank the other end of the original draw off (this is to promote through flow in the interests of best practice according to water regs). But anywhere convenient is also OK. To accomodate the extra draw install a second float valve (beter still another tank in parallel with existing one, but I apreciate that may not be practical.

Put pump in airing cupboard or under bath, you can usually get away with t'ing off for the shower hot supply at the top of the hot water cylinder as the first draw off, best practice is to use a seperate flange of the various types..

To fix the leak you may have to undo the compression nut and olive on both supplies to your shower, remove it from the wall, dig out the leaking one, and replace with new section, new olive, done up correctly, which is clean blemish free pipe, perfect blemish free COPPER olive, tighten up until it bights (with shifter not grips so you have the sensitivity to feel for it bighting), then further 1/4 to 1/2 turn. Check it, if it needs niping up just nip it a little at a time until it is water tight. never use belmished pipe or olives. No need for aditives if you follow this advice to the letter. If you fail, do not keep tightening, undo, wrap two turns of ptfe round olive and try again, don't overtighten.

 

[grrinc]

A single impeller pump is fine, but check the intructions first. Most pumps like to have a new and unique feed tapped from the cylinder ( via an essex flange ) or off the top of the cylinder ( via a surrey flange ). Some allow you to take a draw off from the hot water service, but as long as it is the first draw off. The point of all this is to avoid air being drawn into the impeller. This can can lessen the life and performance of your pump.

Pumps prefer to push than suck so keep the pump as close to the hot water cylinder as possible. Preferably on the floor of the airing cupboard. Their should be an immersion heater power point here that you can spur off from for power. Also, ensure your hotwater temp is 65c or below to avoid cavitation.

If your joint is still leaking, you may have over tightened the nut and split the pipe. This can be a bugger. Why not try a sealing compound such as Plumba or LSX. They will need to dry first. Avoid any oil based compounds.

 

[Wannabe Plumber]

Paul,

Thank you so much for the detailed response.

I think the tank was installed and then a boxed cupboard fitted around it, which doesn't leave me any room to get in and look, or fix in a new tank connector... but I will have a look tonight when I get in. I may be able to get to it from inside the roof/loft.

If I were to do the above there is enough room under the tanks to place/fit a pump. It would mean having to come up out of the pump and elbow out to the right then up again to the mixer, will having an elbow in both H and C pipes cause and further problems with pressure or do pumps handle that problem?

First thing I'll do when I get in is sort the dripping connector, again I appreciate your time.

I shall return if I hit a wall.

Ricky.

 

[Wannabe Plumber]

A single impeller pump is fine, but check the intructions first. Most pumps like to have a new and unique feed tapped from the cylinder ( via an essex flange ) or off the top of the cylinder ( via a surrey flange ). Some allow you to take a draw off from the hot water service, but as long as it is the first draw off. The point of all this is to avoid air being drawn into the impeller. This can can lessen the life and performance of your pump.

Thanks, I'll look into that.

Pumps prefer to push than suck so keep the pump as close to the hot water cylinder as possible. Preferably on the floor of the airing cupboard. Their should be an immersion heater power point here that you can spur off from for power. Also, ensure your hotwater temp is 65c or below to avoid cavitation.

It would be directly under the hot water cylinder and be the draw off the 22mm pipe. I'll have to check the temp, coz it does get stupidly hot sometimes.

Why not try a sealing compound such as Plumba or LSX. They will need to dry first. Avoid any oil based compounds.

Is that stuff ok for plastic pipes?

And thanks again for the reply.

 

[Paul Barker]

Elbow is no problem to the pump.

 

[Wannabe Plumber]

Ok, as I thought there is just enough space to get my hand over the top of the cold water tank... so fitting another draw off using a tank connector could prove a problem if I need to get above it.

So I'm going to buy a pressure meter and test the CW mains pressure. If that is close to 1.5 bar then I'll buy a single pump for the HW. If not, then I'll have to look into fitting the tank connector.

Haven't had time to strip and reconnect the leaking mixer tap connector, will try tonight.

One further question (and sorry if this seems daft!) but do I have to earth the CW and HW taps/pipes leading to the shower, even when I'm using copper pipes on the T's and plastic pipes to connect to the mixer? If so, what's the best method of earthing pipes/taps?

Ricky.