To pump or not to pump

[Riley]

Hi all long time no speak

I need a bit of advice, customer had a shower pump fitted really badly under bath.

This has expectedly packed up and needs replacing. I was asked to quote but I’ve come across a situation I’m not too familiar with.

The property is a flat and bathroom hot water is fed via a cylinder fed by a cwsc maybe a meter above.
The cold water is fed from a massive communal tank some 10 floors up. So as I’m sure you’ll appreciate the flow and pressure of the cold is significantly higher than the hot.

How would you tackle this in terms of a pump?
As it stands I’m not sure that a pump will regulate the difference between hot and cold correctly, am I wrong??
Should I just pump the hot?? And try and roughly balance the two flows?

Bit of advice very welcome

 

[ShaunCorbs]

direct cylinder? or heating in the place?

as for pump difference it too great your looking at a bar on the cold tank

whats the water main like into the property? (flow and pressure)

 

[Riley]

Direct cylinder. The cold I would roughly guess that it’s maybe 2 bar, mains is approx 1.2bar at 14 lpm. If you’re thinking unvented then there’s too much hidden pipework

 

[ShaunCorbs]

Direct cylinder. The cold I would roughly guess that it’s maybe 2 bar, mains is approx 1.2bar at 14 lpm. If you’re thinking unvented then there’s too much hidden pipework

TBH was thinking of a thermal store and use the cold tank to feed the hot water giving you a balanced system

How big l wise is the tank above the cylinder?

 

[Best]

Any chance you could have a new cwt in the flat solely for the cold to the shower pump? Or possibly it for the hot also, therefore doing away with the current cwt that feeds the hot cylinder?

 

[Best]

I was assuming your cwt that feeds the hot cylinder, is a small cwt?

 

[Riley]

Typically with a flat there is no room for anything else. The existing cwsc cylinder set up seems to provide ample hot water according to tenant

 

[Best]

Typically with a flat there is no room for anything else. The existing cwsc cylinder set up seems to provide ample hot water according to tenant

Probably only needs a 25 gallon cwt for to supply solely the hot cylinder.
Pity you couldn't have space for a 50 gallon, or larger cwt.

 

[Riley]

Yeah I’d say 25 gallon tops. So where do I go:
Can’t install new cwsc
Can’t fit unvented
Would you just pump the hot in the flat and cold water coming down from the large tank at the top of the block or would you just pump the hot

 

[ShaunCorbs]

If it's a constant 1.5-2 bar then just fit a pump on the hot to match

 

[Riley]

That’s what I’m thinking. Wasn’t sure if other users would impact it. Or am I over thinking??