gravity fed upstairs shower pressure question

[elmocambo]

We have a gravity fed hot water system in our the house we have just recently moved into. It works fine with the downstairs shower, however we are about to upgrade the upstairs bathroom and are considering installing a shower bath. My concern is that although there is more than sufficient pressure in the hot water taps there, it would be insufficient to supply a shower as the shower head would be only about 40cm beneath the hot water cylinder header tank . Is there a shower mixer and shower head available which could work at this very low pressure?
Also I am not sure if the downstairs shower cold water feed is fed from the header tank also or comes direct from the mains.
I understand installing a motorised pump is a complex and expensive option involving extra header tanks, surrey flange and dedicated electrical wiring installed by a part P electrician. I would prefer a simpler approach so long as worked in an acceptable manner.

 

[ShaunCorbs]

You would need a negative head pump or go with a digital shower with an inbuilt pump

 

[Ben-gee]

Can you raise the cold water storage tank in the loft?

 

[elmocambo]

You would need a negative head pump or go with a digital shower with an inbuilt pump

😧

 

[elmocambo]

Can you raise the cold water storage tank in the loft?

There is no room to move the tank upwards as there are trusses in the way.

 

[elmocambo]

You would need a negative head pump or go with a digital shower with an inbuilt pump

I don't understand why it should be a negative header tank as the shower head is below the header tank?

 

[ShaunCorbs]

I don't understand why it should be a negative header tank as the shower head is below the header tank?

Because your new shower will be probably mains pressure/ high pressure as ideally you want one that can work on 0.1-0.2 bar of pressure even with a pump

 

[elmocambo]

Because your new shower will be probably mains pressure/ high pressure as ideally you want one that can work on 0.1-0.2 bar of pressure even with a pump

What pump and shower would you recommend for my installation?

 

[ShaunCorbs]

What pump and shower would you recommend for my installation?

Stuart turner monsoon universal twin 2 / 3 bar for me and any shower you want

 

[elmocambo]

Stuart turner monsoon universal twin 2 / 3 bar for me and any shower you want

The header tank has a limited capacity of 30 gallons I understand that 50 gallons is the minimum requirement
Is it possible to feed the shower with the direct mains cold water supply and use a 2 bar single pump on the hot water side from the tank if the shower if carefully chosen such as a mira excel or does the pressure on the hot and cold sides have to be equal by being fed from the same header tank?
The reason I ask is that swopping out the tank would be a nightmare as the loft hatch is tiny and space is very restricted up there.

 

[ShaunCorbs]

The header tank has a limited capacity of 30 gallons I understand that 50 gallons is the minimum requirement
Is it possible to feed the shower with the direct mains cold water supply and use a 2 bar single pump on the hot water side from the tank if the shower if carefully chosen such as a mira excel or does the pressure on the hot and cold sides have to be equal by being fed from the same header tank?
The reason I ask is that swopping out the tank would be a nightmare as the loft hatch is tiny and space is very restricted up there.

Have to be equal and what’s your mains pressure and flow like eg refilling the tank ?

 

[elmocambo]

Have to be equal and what’s your mains pressure and flow like eg refilling the tank ?

The mains water pressure seems high maybe excessive. I have had to turn it down at the stopcock .

 

[ShaunCorbs]

The mains water pressure seems high maybe excessive. I have had to turn it down at the stopcock .

Turning the stop tap down increase the velocity so makes it worse better to fit flow restrictors in the taps would say as you have a good mains pressure the pump should be fine on a 30 gal tank due to the mains being good enough to refill it faster than it’s getting removed

 

[elmocambo]

Turning the stop tap down increase the velocity so makes it worse better to fit flow restrictors in the taps would say as you have a good mains pressure the pump should be fine on a 30 gal tank due to the mains being good enough to refill it faster than it’s getting removed

With the stopcock open and not restricting the flow, I collected 3.3L in 6 seconds in a bucket which would be 33L per minute, is that okay?
I don't know how this relates to pressure in bars though.

 

[ShaunCorbs]

Yes so you would be fine on a 12-15lpm shower

 

[elmocambo]

Yes so you would be fine on a 12-15lpm shower

That's great - thank you