Shower pump query..........

[JDLDIY]

Hi there, due to having dismal pressure I am resigned to having a shower pump installed when we install a new shower. It is a gravity system, the hot water tank is in the upstairs airing cupboard and the cold water tank is on the ceiling rafters in the loft.

I am being told that the pump needs to be installed below the cold water tank and so it will need to go in the airing cupboard or under the bath, when I had hoped it would go in the loft, is this right?

The plumber says to install a stewart turner pump as they are good quality, I had one before and found it to be really loud; when I want a really quiet but powerful pump, anyone got any recommendations?

 

[Terrywookfit]

For reliability you will get nobetter than S.T.

Yes the pump needs to be below the source!!

 

[GJS]

All pumps have a minimum input head. Most need a positive head so need to be below the cold water storage tank, some can work with a negative head so can go above the CWS tank. The latter are designed for things like loft extensions and are more expensive.

Some will only require a very small head and can go in the loft, I know a couple of people that have these.

'Hope that helps.

 

[Terrywookfit]

All pumps have a minimum input head. Most need a positive head so need to be below the cold water storage tank, some can work with a negative head so can go above the CWS tank. The latter are designed for things like loft extensions and are more expensive.

Some will only require a very small head and can go in the loft, I know a couple of people that have these.

'Hope that helps.

They may work on negative head But will still require a flooded suction line!!

 

[JDLDIY]

They may work on negative head But will still require a flooded suction line!!

Can you explain that for me Terry please?

 

[Terrywookfit]

Although the pump will deliver the water above the water level in the tank.

The pump needs to be fitted below the connection points on the hot and cold supplies to ensure it is always full of water!! (usually a min of 300mm).

 

[JDLDIY]

Although the pump will deliver the water above the water level in the tank.

The pump needs to be fitted below the connection points on the hot and cold supplies to ensure it is always full of water!! (usually a min of 300mm).

So with the hot water tank being in the airing cupboard I'll never be able to have the pump in the loft? You see loads of pictures/diagrams (especially of these digital showers which have pumped control units) with the pump shown above the shower unit in the loft, but I'm sure most homes in the UK will have HW cylinders in airing cupboards like mine....

 

[oompah]

Why not go for a power shower with an integeral pump we have a mira event taking the hot feed from the airing cupboard hot water tank and cold from tank in the loft.

 

[stardanny]

Yes you can.

Other shower maker ( can't remember the name AQUASIA or ? ) They have remote shower control rail with head and a pump unit that can be used in loft. It can be used with tank fed cold water and cylinder fed hot water. I fit once before and they are good, but price? Whoa.

 

[JDLDIY]

Other shower maker ( can't remember the name AQUASIA or ? ) They have remote shower control rail with head and a pump unit that can be used in loft. It can be used with tank fed cold water and cylinder fed hot water. I fit once before and they are good, but price? Whoa.

Yes Aqualisa and I think Mira both do showers like that, but at the end of the day the control box located in the loft will have a pump in it, so why can't I just sit a normal pump in the loft?

 

[stardanny]

Aqualisa and mira pump unit are designed to sited in loft where normal pump can not sited in loft. Has to be in airing cupboard.

There is other way, is to raise the cold water tank up say 1m depend on MI for min head height, depend on space in loft.

 

[GJS]

The position of the HW tank is irrelevant as it is presurised by the cold water tank in the loft. The pressure at the input to the pump depends purely on the vertical distance from the cold water tank to the pump input.

There are other consideration though when siting a pump, mainly keeping air out. Here the position of the pump relative to the HW tank can be important. Here's the instructions for the pump I just fitted, loads of info:

http://www.salamanderpumps.co.uk/Download/instructions.pdf

 

[JDLDIY]

Many thanks GJS, read through the instructions you've posted, most informative. To be honest I'm beginning to do 180 degrees on this whole subject and even though it's going to cost me more, I'm contemplating having an unvented cylinder fitted. That way as I see it I won't have to concern myself with the positioning and noise from a pump, I should have loads of pressure to all the sinks and baths and showers in the house, not limited to choice of taps etc.

Please correct me if I'm wrong in my thinking! Are any of these cylinders better/cheaper than the rest? People always talk about megaflows but they're made by other manufacturers aren't they?

 

[Doctor Drivel]

Forget all this noisy, vibrating pump nonsense.

1. Fit a Trevi Boost venturi shower (high pressure showers ona gravity system)

2. Fit one of these. A cylinder with a high pressure shower coil inside that instantly heats cold water, so mains pressure on hot and cold to the shower. Gravity DHW at all other taps.

http://www.copperform.co.uk/mains_pressure/ultra_shower/index.htm

3. A plate heat exchanger, low noise bronze pump and flow switch (on the cold main to the plate) off the existing cylinder instantly heating the cold incoming mains and having a high pressure mains fed shower. This is a cost effective option. Plate heat exchangers are around £70, a bronze pump from ebay £50 and a flow switch around £25-30. That is £150 pus a check valve and some pipe and fitting and full mains pressure showers. Beats a Power shower pump and silent.

Below: a plate heat exchanger.

Below: the flowswitch - no moving parts:

If difficult to source DPS or Gledhill will supply a Plate Heat X. The model for the 125 litre Systemate will do. If you can get another cheaper source then try them.

http://www.bes.co.uk or Screwfix will supply most of the fittings. They don't do the plate heat exchangers.

Farnell will supply the flow switch http://www.farnell.co.uk Farnell number: 1006771 with 22mm compression joints.

Flow Switch, makers site: The FS06
http://www.gentechsensors.com/productTemplate.asp?ProdId=113
This flow switch is about the best - very good.

 

[Doctor Drivel]

Many thanks GJS, read through the instructions you've posted, most informative. To be honest I'm beginning to do 180 degrees on this whole subject and even though it's going to cost me more, I'm contemplating having an unvented cylinder fitted.

Avoid an unvented cylinder. They need an annual service which costs and can do this:
http://www.waterheaterblast.com

They are also expensive!!!

Go heat bank/thermal store, which are superior and failsafe.

See my post on how to get mains pressure showers cheaply.