Shower pump advice

[umar299]

Hello everyone,

Hope all is well

I am renovating my bathroom and have done a lot research, although am still unsure as to what pump I require.

Firstly, let me explain what water system I am dealing with...
I have a gravity fed system, with the cold water tank being in the loft and feeding just the hot water cylinder, which means the rest of the cold water taps are fed through the mains. My hot water cylinder is located on the first floor, adjacent to the bathroom, I am refurbishing.

I would like to install a single pump to feed both basin and shower. Having spoken to pump wise they are suggesting I install an negative head shower pump, because I am pumping the hot water against the cold mains, however I do not understand why.
The question is can i get away with a positive head pump?
or will it cause complications?
and what pump would you recommend for my needs that will:
a) provide sufficient pressure.
b) be quiet.


Thank for reading

 

[Pumpman6]

Hi, yes I agree with pump wise. When pumping gravity hot V's cold mains to common mixer always use a negative head pump. If you dont you are likly to find either the pump wont start or will cycle on off on off whilst in use. Negative head pumps have run on timers and rest at pressure as does your cold mains.

In my view the Monsoon universal (= negative head in Stuart Turner) are the best pump on the market. Look at the Monsoon universal singlel, size 2.0, 3.0 or 4.5 bar. size to be determined by pressure you want as a user, cold mains pressure and what the shower equipment requires.

All pumps make noise and the more powerful that are the more noise thay make. There are lots of claims very quiet, Whisper quiet etc but all make noise. Pump size, Location, Acoustics of house, water temp etc all make a differance on noise emitted.

 

[picasso]

I am surprised pump wise recommended any pump with the cold main suppling the shower/basin, its never a good idea to mix different pressures on bathroom outlets, you are creating problems for the future, if you want a reasonably fault free installation pump both the hot and cold from the tank in the loft (and you can use a positive head pump)

 

[umar299]

Thank you for the help.

Okay if I were to pump both the hot and cold from the tank...
would it be possible to tee of the cold water pipe coming from the cold water tank going to the hot water cylinder, or would that be bad practice?

Also am not entirely sure if my cold water tank is large enough to cope with delivering to both the shower and hot water cylinder, when showering. Hence, the reason I wanted to fit an single impeller pump, to pump the hot water and use an Pressure Equalizing Valve or Pressure Reducing Valve to balance the hot and cold, and use a check valve on the hot.

Thanks again.

 

[picasso]

Its very bad practise to tee off the feed to the cylinder, if your going to do it properly you would need to run a dedicated cold feed from the tank to the pump and likewise with the hot, up grading the loft tank needent be overly expensive as your having work done anyway, it may seem overkill at the moment but will it save you problems in the long term.

 

[Pumpman6]

Bad practice.

 

[umar299]

Okay am convinced it should be done properly.

Appreciate the quick replies.

Thank you

 

[danplumb]

If you are going to pump your hot and cold from the cistern in the loft make sure that the outlet for the hot to the cylinder is above the cold outlet to the pump so if the water level in the cistern drops too low the hot water cuts out first preventing scalding in the shower.