Shower pump advice please!

[tonywhiteley454]

Hi All. First post on here so I hope I've got this right. 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 Slamander CT50 into the supply where the present H & C pipes lay in the loft 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. 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 difficult to achieve and a major re-plumb 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 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 thanks to all. Regards, Tony.

 

[Whn1]

The positive head needs to be between the shower head and the storage tank not the pump and the tank.

 

[Whn1]

And if you didn't have a positive situation you can just fit a negative head pump.

 

[tonywhiteley454]

Thanks Whn1 for your prompt reply. So if I understand your advice correctly my original plan (Pump in loft, supply from hot storage below in airing cupboard) would be ok but only with a negative pressure type pump? Thanks again. Tony.

 

[nickelarsed]

If you go to the salamander pumps website, go to the downloads section you can download pdf diagrams of exactly how to install their pumps. If you follow them you can't go wrong.

Downloads | Salamander Pumps | Quality | Technology | Performance | Value

And if your shower head is below the bottom of your tank then you are in a positive head situation, no matter where you put the pump.

 

[petercj]

Or save yourself a lot of work and fit one of these...

Aqualisa Aquastream Thermostatic Power Shower - Aqualisa available at Plumbworld

Low voltage for the ultimate in safety and ease of wiring (no need for heavy cabling), just as powerful as a pump, likely to last as long, if not longer, and with a full range of spares available, plus comes with a 3 year onsite warranty, and it won't transmit noise through the floor/ceiling.

 

[tonywhiteley454]

Thanks Nickelarsed and Peter CJ. I'll certainly check out the Aqualisa unit, sounds like it could be just what I need! Meanwhile back to the original problem. Indeed that is what I thought, that as long as the shower pump is below the bottom of the cold water cistern then the pump is getting positive pressure and ok. The reason I'm confused is that I called the Salamander help line to run through what I planned and I was told that what I planned wasn't good. The pump needed to be down by the HW tank and a Surrey flange was not suitable it had to be an Essex, and that running the hot supply from the pump (By the HW cylinder in the airing cupbpard) up into the loft then along to the shower feed pipe would probably require a negative pressure pump. This set-up would require a major re-plumb, more than I would like to attempt. If all I need is a pump (be if pos or neg) in the loft and a Surrey flange then for me it would be quite do-able. I had looked at the Salamander PDF's before however I couldn't find one that specifically refered to the CT pump range. Thanks again to all for your help and advice apologies to all if I'm making this heavy going when it isn't! Regards, Tony.

 

[nickelarsed]

Well Listen to the manufacturer is the rule, the reason they want the pump by the H/W cylinder with an essex is to stop aerated water getting into the pump. Also it wont like having to suck water out of the cylinder upwards, it should flow down into the pump. Its designed to pump not suck. Best advice onm this thread so far is to look at aqaulisa. Either the one in the link or one of the digital systems. Make your life much easier.

 

[tonywhiteley454]

Thanks to all who replied so promptly. advice much appreciated! Going to check out the Aqualisa and maybe go that way. Regards, Tony.

 

[Whn1]

Just because the pipes go back up doesn't mean it'll have to suck, if enough waters passing to activate the flow switch it'll pump and not suck.

 

[nickelarsed]

true, badly worded but they recommend by the base of the cistern and at least below the draw off to stop it sucking air in.

 

[tonywhiteley454]

Hi All. Been checking out the Aqualisa as advised. Came across the Triton T40i as an alternative. Anybody on here got any experience of the unit? Be good to know if it's got good reliability and if it's noisy in use. As before any advice most welcom and thanks. Tony.