Do I need a Negative Pump….

johnthenu · 13 Sep 2010

Hi All,

The water pressure in my shower is low; hence to increase the pressure I have purchased Salmander Shower Pump 2.1 Bar CT75.

Cold water tank is above the hot water cylinder. Shower Mixer is at around 20 % height of the hot water cylinder.....But the actual shower head is in level with the top of the cold water tank.

http://i35.tinypic.com/14098jo.jpg
http://i37.tinypic.com/2d168wi.jpg

In this situation should I need to use a negative head pump or can I just use the pump I purchased.

What will happen if I just fit the pump I bought, as I don’t think I can exchange it....

Any advice will be greatly appreciated.

wetshoes · 13 Sep 2010

You need a negative head pump.
Or fit something like an Qqualisa Visage (pumped version) - there's probably not much between the two in price

Boxerman · 13 Sep 2010

Salamander do a negative head kit for that pump, RCM 3 is the product code, cheaper than a new pump!!!

http://www.h-i-e.co.uk/acatalog/Right_RHP.html

wetshoes · 13 Sep 2010

Boxerman said:
Salamander do a negative head kit for that pump, RCM 3 is the product code, cheaper than a new pump!!!

http://www.h-i-e.co.uk/acatalog/Right_RHP.html

But you'll need two of them !

Bon · 13 Sep 2010

Does the shower currently work under gravity? If so you don't need a negative head kit.

Other things to consider;

Does the cold supply to the shower run from that tank too?

Is there any space in your loft directly above?

The thing to consider when fitting a shower pump is that because of the higher flow rate, your tank will empty much faster than a gravity shower therefore it is often wise to increase the volume of your water storage.

Axel · 13 Sep 2010

If there is little or no flow without a pump, and it's not enough flow to activate the pump, there is the inelegant option of fitting a pullcord ceiling momentary action switch that will start the pump. The pump will turn off automatically when taps are closed.

looneyfitter · 13 Sep 2010

Axel said:
If there is little or no flow without a pump, and it's not enough flow to activate the pump, there is the inelegant option of fitting a pullcord ceiling momentary action switch that will start the pump. The pump will turn off automatically when taps are closed.

Agree, will do the same job as a negative head kit

ChrisR · 13 Sep 2010

If you use a shower with a free hose, you'll be able to just lower it to get some flow to turn the pump on. Naff but it works!

Be careful where you get the hot from.
See the level of the air in the vent pipe.
If you take HW from anwhereon the red pipe it's very likely to suck air down the vent, which breaks Salamanders quick.

I suggest you use an Essex flange, which comes off the side of the tank, as shown pink. Alarming to drill the tank, but very quick to fit the flange - all over in 5 minutes.
CW would come fromthe cistern, pipe not shown

Bon · 14 Sep 2010

Do you pay extra for the fish?

Axel · 14 Sep 2010

What do you expect if you use a flange from Essex?

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Do I need a Negative Pump….

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