Booster pumps

[SlimD]

Hello,

I'd like to pick some of your brains if I may?
Ive just replaced a kitchen tap in a ground floor flat and the customer is complaining that the hot flow is a trickle, which it is. It was before too.
They have an open vented system with the hot cylinder on the floor in a cupboard off the kitchen and the cold cistern on a platform just above with its base at maybe 1.2m from the floor. The base of the cistern is only about a foot or so above the level of the top of the kitchen tap so no surprises why there's crap pressure.
What I want to know is what would be the best type of pump to put on the hot from the cyclinder to boost the pressure? I'm thinking a negative head pump but just wanted to bounce it off you guys with more experience as I've not fitted a pump before.

 

[Chalked]

Yes a single impeller negative head pump will do the trick. You will need to take a dedicated connection from the cylinder. Best to use a "Surrey flange" or an "Essex boss" if you have any showers, or tank fed supplies you will need a twin impeller pump to fed the cold side.
Buy the best you can afford. Stuart turner make decent quality ones.

 

[Ch4 plumbing]

TBH if they have a problem with all the outlets (HOT/COLD) then fit a twin impeller pump.

 

[PlumbBobBob]

make sure the cold water cistern is big enough for a pump and won't run dry

 

[SlimD]

Thanks guys.
The cistern is easily big enough not to run dry as it's got to be at least double the size of the cylinder. The cold is not affected as the kitchen cold is straight from the main. It's just the hot that has crap pressure due to very poor head so only need a single impeller pump.
I was looking at the Surrey flange as a possibility to so thanks for confirming what I was thinking.
Thanks again.

 

[SlimD]

The pipe to the hot tap is run in 15mm across the length of the kitchen. As an alternative to a pump do you think that re-running the pipe in 22 would make much difference or would you go straight for the pump?

 

[Chalked]

You will increase flow very slightly. But no pressure, as this is based on head of water above the point of use.

 

[unguided1]

No, if I'm not mistaken the kitchen tap is probably some cheap european rubbish with 6mm Id flexis so upping the volume to 22mm will make no difference, there isn't enough gravity to run the tap! Pump is only option!