combination cylinder - poor hot pressure. New thermal storage cylinder?

[scott2hot]

A customer of mine has asked me to solve her poor hot water pressure. She has a direct combination cylinder. I've advised her that there is no easy/cheap way to do this. I've suggested fitting a direct combination thermal storage cylinder but after seeing the prices of these - best part of £1000 i'm not sure she'll be willing to pay this much. Is there a cheaper alternative? I don't think she's too keen on a unvented system due to the annual serviceing etc. Secondly how long should one of these take to fit - I've not come across one yet?

Many thanks

 

[AWheating]

fit a tank high/higher in the loft??

a thermal store or unvented could only be fitted if the cold main was suitable really, what was the cold main like? pressure and flow?

 

[Plamber]

well with a thermal store the hot pressure will be the same as the cold. I like them but you never really see much of them around. but like you say they are not cheap.

Is it in a flat or a house? Usually combination cylinders are in flats due to space or lack of.

 

[mountainman]

Nothing much you can do unless the combination cylinder has the large cold tank.
If it's the usual small one then you are burgered.

 

[scott2hot]

Unfortunately it's a dormer style house, there's no attic space for the usual CWSC and Hot Cylinder. What's the minimum pressure and flow needed for a thermal store? - surely the hot pressure would be the same as the cold. Thanks

 

[AWheating]

it depends on the cylinder manufacture but normally you need 1.5bar dynamic pressure and 20ltr per min as a min. could you not fit an combi boiler?

 

[TBServices]

Can't you get a small tank in cupboard above a standard cylinder?


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[Plamber]

I never realised there was a minimum pressure for a thermal store?

Yes with a thermal store the pressure is the same hot and cold.

 

[AWheating]

there would be no point fitting a thermal store or unvented cylinder without a good cold water performance, with 20lpm you can assume you may get 10lpm on the hot and the same on the cold when they are both run which is not great.

 

[mountainman]

Seems there is some confusion here.
The thermal store is not pressurised, it only transfers heat from a large bulk of very hot water into a coil containing water at mains pressure.
The cold is also at mains pressure.

At the end of the day I doubt that the customer would consider the expense of such a system.

 

[scott2hot]

Thanks for all your replies, i'll have to check out her mains pressure and flow rate. Fitting a combi is not really an option, there's no gas in her village so oil would be the only solution - even more expensive than a thermal storage cylinder. If there is room in her limited loft would it be cheaper to fit a CWSC and hot cylinder complete with a pump?

 

[Roger Welton]

Bit of a left field solution, how a bout a LPG fired multi-point water heater (or combi and heating system if funds allow)