Changing from vented to unvented system - advice please! All aspects of plumbing questions and answers, help, tips and information

[Big Jim]

Hi, to cut a long story short, am going to change from a gravity-fed system to a mains pressure system, partly because I need to remove the existing gravity-feed tanks from the roof space, and partly because I need a new boiler.

I will only be needing a domestic hot water supply (ie, no central heating) and will need water for a kitchen, and 3 bathrooms.

Question: Should I get an on-demand boiler (multi-point) system, or have a more 'traditional' system with hotwater cylinder? And should I go for vented or unvented?

Any advice, information, or related comments welcome!

[htg engineer]

"partly because I need to remove the existing gravity-feed tanks from the roof space, and partly because I need a new boiler."

Why ? to gain space or are the tanks knackered ?

If you stick with open vented you will still need the tanks - or new tanks.

Unvented your system will work off mains pressure - no tanks, just a cylinder. (probably the best in this case)

A combi would be pointless if you're not using the heating side, and a instantaneous water heater - would be the best bet - but not much good if you use more than one bathroom at a time.


htg

[Big Jim]

Hi Htg,

Thanks for the reply.

I'm getting rid of the tanks because they were housed on the (flat) roof, which is being replaced due to multiple problems, and I would prefer to keep the surface as simple as possible so the tanks have got to go.

Having read this:

Google "gasapplianceguide.co.uk/Mains_Pressure_Hot_Water_Systems.htm"

I was under the impression it was possible to have a vented system that wasn't gravity fed... is that wrong?