Fitting shower pump

[tonywhiteley454]

Hi All. Hope I'm doing this right as it's my first post.
My query relates to installing a shower pump in my old gravity fed system. The supply presently is as follows:- Cold from the base of the cistern in the loft. Hot from low on the hot tank overflow also in the loft. I intended to install a Salamander CT50 into the supply where the present H & C pipes lay on the loft floor before going vertically down (Embedded) in the bathroom wall to the shower head. Seemed to me that the pump if installed straight into the present system would draw air into itself from the hot overflow take-off. I planned to fit a Surrey flange into the hot tank (Below the loft & same floor as the shower) bring the new hot supply up into the loft and supply the pump in the loft. The cold would remain as before, supplied from the cistern. I've been told that this would not work as there would not be a positive supply to the pump and the pump should be fitted in the airing cupboard next to the hot tank. Possible to do but very difficult to achieve, no space in the airing cupboard to fit a pump. It would require a major re-plumb, to much for me at least. What I find difficult to understand is that if the present system supplies a reasonable shower, albeit with not much pressure, then with a hot supply from the HW tank and existing cold from the cistern surely there would still be enough positive supply provided from the cold tank above in the loft so the pump could boost this to a satisfactory pressure without a problem. Attached sketch to maybe explain it a little better. Any advice and help most welcome and many thanks. Regards, Tony.

 

[JohnKay]

Hi there.
Your proposal is basically sound. the pump must have it's own supplies, surrey flange, as you suggest, and new cold from tank.
As for fitting in the loft, I've come across problems in the past that have meant raising the tank. I suggest having a word with Salamander, they can advise you on the minimum head required for the CT50.

Another alternative would be to install behind the bath panel, but you must ask a qualified electrician to advise before considering this.

 

[tonywhiteley454]

Hi. John.
Many thanks for your advice. I have previously contacted Salamander and they more or less insist the pump must be alongside the HW tank in the airing cupboard, which isn't an option without major plumbing work. Their info sheet suggests that the pump should be at least 600mm (24") below the bottom of the cold supply tank, This isn't possible presently if I site the pump on the loft floor, although this does give a head of 24" to the pump but this measured from the max water level in the cold tank and not from the base. So although I'm not following their advice, I was just hoping to find out from the forum if there is some allowable tolerance, although the manufacturer wouldn't advise it as they want to make sure everything is just right in case of guarantee claims? Thanks also for the tip about under the bath, unfortunately again space there is very tight. Look forward to any other advice or tips. meanwhile I'll continue to give it further thought..........! Regards to all Tony.

 

[petej]

As JohnKay says if you do not follow the manufacturers instructions they have a get out straight away, and depending on the pressure of your rising main the tank may not stay full so the head of water on the pump will drop and maybe cause cavitation in the pump impellers (although it will probably work OK).
If you have the head room it is usually an reasonably easy DIY job to raise your cold water storage tank up onto a substantial base thus gaining "head" which is always a good thing and it will allow you to fit the pump in the loft and keep within manufacturers dimensions, in fact if you can raise the tank high enough you may get away without the pump (usually horribly noisy things) from my experience !
If you do go for the pump make sure the cold tank is large enough as they do get through some water .
Pete

 

[tonywhiteley454]

Thanks Petej.
I'll have another close look at the cold water tank and see how involved raising it may be. It's worth considering it as an option either on it's own or with a pump........More to think about. Ta! Regards, Tony.

 

[tonywhiteley454]

Hi All.
Raising the CW tank looks a nightmare. Been advised about using an Aqualisa Aquastream, while checking came across the Triton T40i as an alternative. Anybody on here got any experience of the unit? I'd like to know if it's got good reliability and also if it's noisy in use. As before any advice most welcome and thanks. Tony.

 

[JohnKay]

Hi Tony

Looks like you've found an answer with the Aqualisa, I've heard this is a good unit, as is other products from them. The Triton is not quite the same.

As I've not fitted the Aquastream myself, I can't advise on the installation requirements, I'm sure Aqualisa can advise.

As this is an electrical appliance in the bathroom, you must get a registered electrician to connect it.

 

[bethany22]

Yes I agree with Johnkay, You do not need to DIY when you are unsure of your home safety.

 

[tonywhiteley454]

Thanks guys.
Appreciate your advice. Regards, Tony.