How to add a Shower Pump to my existing plumbing?

This is my first post, so please bear with me....

I have a new(ish) build house, which is around 12 years old. The hot water system is gravity fed with a large header tank in the loft.. The shower in the en-suite is a simple thermostat/mixer type.. I looks good, as its just a knob/hose sticking out of the all, but its pretty useless.. Its got a low flow rate and almost no pressure, but its barely acceptable..

The shower gets stiff from time to time, so every year or so, I have to dismantle the valve, de-scale it, grease it and re-install and this was my job for the weekend.

Whilst doing this I started to wonder if its worth ripping out the entire en-suite and having a completely new bathroom installed... It would just be nice to have a powerful shower with a bit of flow.

So my topic of discussion in work today was "showers" and someone asked why I simply didn't fit a Shower Pump.. A few mins later I was looking at Screwfix and then Ebay and figured that a 2bar Salamander CT75 would be a good choice.

I simply assumed I could break into my exisiting 15mm cold/hot pipework feeding the shower and connect the pump, but then I started to read about "Essex Flanges" and thought I needed some advice.

So I spoke to Salamander who have told me.

1. I need to change the flange on my tank to an 'Essex' type and then re-jig the pipes to other services and the vent.

2. Provide a 22mm hot feed directly from the tank to the pump

3. Provide a 22mm feed directly from the cold supply to the pump.


If I have to do the above, then its not something I want to do myself.. I can turn my hand to most things, but I don't like plumbing.


What would happen if I just cut the existing 15mm pipes and inserted the pump? No Essex value... no direct feeds.. Would it work? Would it cause problems elsewhere?

I am going to get a quote from a plumber, but I would still like to do most of this myself.

Jon

If you don't follow the pump manufacturer's instructions, they won't honour the guarantee.
The reasons for separate feeds to to the pump are many, including:
1) To prevent aerated water from your hot water cylinder or cold water tank feeding the pump, which will damage it [the pump]
2) To ensure adequate supply of hot and cold water to pump
3) To provide pump with nominally equal pressures of hot and cold water.

What you suggest would be quite wrong, and would probably damage the pump. Think about what would happen if you opened another tap - the pump would suck water and then air from the open tap...

You are right... But I am not sure how running fresh pipe would prevent what you said.

The bit about the aerated water is exactly what they told me. ANd the reson for changing the Suffolk flange to an Essex.

But I still can't get my head around the 22mm feeds.. Looking further into this, the pump comes with 15mm flexible pipes.. So it looks like its intended to be fed with 15mm pipe, not 22!

Jon

But I still can't get my head around the 22mm feeds.. Looking further into this, the pump comes with 15mm flexible pipes.. So it looks like its intended to be fed with 15mm pipe, not 22!

Click to expand...

You may well be able to use 15mm if the pump is close to the cylinder. Again, the manufacturer's instructions will tell what is acceptable; the general idea is to have the feed to the pump as non-restrictive as necessary/possible.

You are right... But I am not sure how running fresh pipe would prevent what you said.

Click to expand...

If your pump is supplied from a pipe which is only connected to a tank (or cylinder), then the only flow of water will be from that tank to the pump. The tank connector is situated away from the mains feed which disturbs the water causing aeration. The cylinder connection ensures that the water is drawn in a manner which minimises the draw of aerated water, i.e. not right at the top where air collects.

Running a pump off a shared pipe will mean that when the pump is running, water will not only be drawn from the tank, but also from the other outlets. So turning such outlets on will result in air being sucked in and not water being forced out; this is bad on many levels.


Have a look at the Salamander pump instructions online - they are quite informative.

Edit: There was a bloke on here a few weeks ago who posted some nice pictures of his shower pump plumbing project. Hopefully a search will find it.