Shower Pump under the bath without using a flange

[Multiplex]

Hey,

I've moved into a new flat which has the following configuration for the hot water (except without the pump of course):

Now I want to put the pump in without going through the mess of using a surrey flange. There are only three hot taps in the house, one in the kitchen, and two in the bathroom.

Question: Is it possible for me to fit the pump under the bath serving the taps in the bathroom but not the kitchen?? Or do I have to fit the pump earlier in the pipework so it serves both the bathroom and the kitchen?? Will it cause any problems to just install it under the bath where I have easier access to the pump?

Many thanks,
Simon.

 

[Balenza]

Multiplex wrote

Now I want to put the pump in

Why do you need the pump ?.

 

[Multiplex]

Because the cold water tank is in a cupboard at chest height and there is no pressure at all on the hot tap. As soon as you raise the shower hose the water flow dies.

 

[gas4you]

Pump straight off existing hot supply will cause air to be sucked in via vent pipe. Put the surrey in or an essex

 

[dal5band]

I've had a pump under the bath serving a shower mixer above the bath (separate from the bath taps). It has worked fine for 4-5 years. However, we have good water pressure as the tank in the loft is on a raised platform, 3 feet above the loft joists and also the bath taps are not connected to the pump.

Use a shower pump with a flow adjustment so you can turn it down a bit if it causes problems. Should be Ok for a normal shower - 10-12L/min.


If the flow in the kitchen is good enough, leave well alone. Other than for a shower, a pump cutting it & out every time you turn a tap on will be a nuisance because of the noise.

 

[dal5band]

Sorry - didn't ralise your tank was so low. Better listen to the experts.

 

[Balenza]

Multiplex wrote

Because the cold water tank is in a cupboard at chest height and there is no pressure at all on the hot tap. As soon as you raise the shower hose the water flow dies.

Fair enough. Mines the same.
I just stay on my knees whilst showering. Not the best solution but it works for me.
Dont like the idea of a pump in a bathroom. Electrics and all that.
I would just install new pipework and fit the pump in the hotpress.
Failing that a Trevi boost may be an option or similar venturi type shower. Though I have been trying to source one lately and my sources tell me that Trevi have stopped manufacturing them , though I noticed a few online suppliers selling them though availability may be limited.

 

[TicklyT]

Because the cold water tank is in a cupboard at chest height and there is no pressure at all on the hot tap. As soon as you raise the shower hose the water flow dies.

You may have a problem getting a shower pump to start unless you use a negative head pump.

 

[Multiplex]

Thanks for all the replies.

I know that the flange is only necessary if there are more taps feeding off the same pipe to the shower pump. That isn't really a problem in a small flat.

The real question is, if the pump is under the bath and is not in use, and someone runs a tap in the kitchen how will this affect the pump when it is run after that?

I think basically I'll stick it under the bath using the existing pipework and we'll see what happens.

Simon.

 

[Balenza]

Multiplex wrote

I'll stick it under the bath using the existing pipework and we'll see what happens.

Are you using a double ended pump for hot and cold pumping.?
If so, you need to make sure the cold supply to the bath is gravity fed.
Some pumps have minimum flowrates to activate the flow switches.
If you dont have these then you need a negative head pump as already stated above.
Also some have maximum distances specified for the suction run.
Techflows is 4m I believe. Cross these and you have more trouble.
Also connecting the pump without using a dedicated feed from the cylinder is not the best route to take. Air entrainment in the suction supply leading to cavitation due to an extended suction run and the higher the temperature in your cylinder then the worse this gets.
Then your back on here in a few months wondering why it dont work.

If your diying the pump install then adhere to the manufacturers instructions to the letter and you should have no problems.

 

[ChrisR]

I know that the flange is only necessary if there are more taps feeding off the same pipe to the shower pump.

Wrong. Your pump is liable to suck air down the vent pipe.
Fit a flange, a Warix or Essex takes all of 10 minutes.