odd cylinder pairing

[larrytheleak]

doing a new ensuite which will have 2 basins loo & shower the property has an odd arrangment for hot water production & storage
ground floor utility has oil boiler with rad circuits to ground & first floors swimming pool circuit & indirect cylinder circuit which is on ground floor next to boiler
this cylinder 1500 x 600 has 28mm cold feed from tank in loft above 1st floor
expansion is also 28mm vertical with tee to some ground floor taps also to shower pump which feeds 1st floor taps
there is an additional direct cylinder 900x 450 in ist floor with 28mm cold feed 22 expansion with essex flange supplying pump for shower in room adjacent
hot water seems to be produced by 28 expansion from ground floor teed into the 28mm cold feed about 300mm up from base of cylinder
this expansion has a non return valve prior to teeing into cold feed if no hot water has been drawn off for a while all pipes are hot including cold feed to height of cylinder
when hot water is drawn off expansion back as far as non return valve gets cold as you would expect
has anyone such an arrangment before
the pump next to direct cylinder i intend using or upgrading to cope with two showers running simultanoesly
with the present setup of expansions i think maybee hot water would work better with only cold feed to lower cylinder
after present alterations are finished there will be 2 bathrooms with shower only and two with shower & bath
ideally stored hot water should be 400 litres cold 800 litres
the occupants are retired couple
occasional full house of family & friends
if i have to increase the amount of stored hot water an additional indirect cylinder linked to existing on ground floor might be best solution only using it at peak demand
has anybody got some thoughts as way forward

 

[simond]

This is very difficult to follow.

Clearly both cylinders should have a separate cold feed from the tank, I don't understand the non return valve scenario. Are you looking at a secondary return?

If you are worried about the capacity then make the cylinder bigger. Are the hot water cylinders connected together, or feeding separate areas?

If you are not sure, an alliance with a company that specialises in boilers and water plant, but does not do bathrooms, may be a good long term bet. There are a fair few of us out there that do not do bathroom fit outs.

 

[larrytheleak]

thanks for reply simond
there is no secondary return
direct cylinder on first floor seems to be heated by expansion pipe of lower indirect cylinder teed into cold feed
prior to being teed in the expansion has a non return valve
i assume this is to stop cold feed water mixing with hot draw offs on exp prior to non return valve
when hot is drawn off direct cylinder cold feed flows as normal
with direct cylinder cold feed isolated all hot taps still flow
i am back on that site tommorow and will have a better look