boiler system with no loft tanks

Hi,

My bungalow has a tall OSO hot water cylinder with a red pressure/expansion ?? small tank, all next to the boiler.

There is No cold water tank in the loft.

Boiler is a Worcester Greenstari, RSF gas Condensing system.

My daughter's cottage has an old Poterton with 2 tanks in the loft & a standard hot water tank in a bedroom cupboard.

If she installs the Worcester boiler as I have, what does she have to do to avoid having tanks in the loft?

Sounds to me like you have a sealed systems and the daughter has an open vented system.

It's not the boiler she needs to change, but her hot water tank.

Any boiler can be plumbed unvented or vented (tank in loft) but you need a special unvented cylinder to withstand the higher pressure of an unvented system.

Once you have had an unvented system with mains pressure hot water you will NEVER want to go back.

Do you have know if your daughters is a Y or S plan? If its a Y-plan you would also have to install a two port valve when installing the Unvented cylinder and regardless of what plan she has you would also have to install a high limit thermostat in series with the hot water temperature control thermostat. These thermostats normally come combined and fit in/on to a dual pocket on the cylinder.

Thank you all,

Her boiler is very old with minimal spares available & decided to install one like mine. 

It must be Y plan & as per your suggestion will get the appropriate H/W Cylinder OSO or similar, & whatever is needed to make it Unvented & decommission the loft tanks.

With this system fitted will the shower pressure be adequate without a shower pump?. The mains pressures around here are quite high.

I am no plumbing expert, but if it is a low usage household would converting it to a combi system not be a way forward, does away with F&E tanks and hot water tanks pressurised or non.  Frees up a cupboard and gets rid of water in potentially freezing lofts.

Best thing I did re plumbing in my house and the shower is now brill.

A plumber I called for a leak in the shower suggested that to change a vented system to unvented increasing the water pressure from 1bar to 2.5bars would cause havoc in the old pipes & joints as the house is 60yrs old.

If they are all copper and soldered then unless you had some severe corrosion issues, I'd probably say it'll be alright. 

Thank you all.