Opinions/advice required please

Bollards

I need some advice about which quote to go for from the following. Firstly I'll tell you what we already have:
Ravenheat condensing boiler with a water tank in the airing cupboard and an "open"? central heating system.
3 bedroom detached house with a bathroom and ensuite with both showers running off the mains.

Quotes are as follows:
Vaillant Ecotec 618 boiler and adapting heating system to a sealed system
or
Worcester Greenstar 24i boiler

I'm not sure whether we should convert to a sealed system as I don't know what difference this will make. I haven't included the costs at this point as I am not driven by how much it will cost, but what would be best for the house.
I have noticed on these forums that both of the boilers are quite popular and seem to be reliable.
Any advice will be appreciated!
Thanks.

mute_posting

Out of interest, why are you replacing your existing condensing boiler?

MP

Bollards

mute_posting wrote: »

Out of interest, why are you replacing your existing condensing boiler?

MP

Because it is the most unreliable piece of junk I have ever set eyes on! We have spent far too much on it already, unsuccessfully trying to solve why it sometimes will light and sometimes not. Three different companies have tried different tactics to no avail. We inherited it when we moved in and I think that the previous owners installed it themselves (and they weren't corgi registered!) It would be great if I knew that we would have heat and hot water when we woke in the morning in the middle of winter!

bobmedley

Can't comment on the boilers (I use oil), but we do have a non-vented system - it's been in use for 9 years with no issues at all and a big benefit is you get mains pressure hot water all over the house. There is also no tank in the loft with any hassle that might ensue from that.

There is a fairly basic guide here

http://www.cus.net/gas/subcats/gasheating.html

mute_posting

bobmedley wrote: »

Can't comment on the boilers (I use oil), but we do have a non-vented system - it's been in use for 9 years with no issues at all and a big benefit is you get mains pressure hot water all over the house. There is also no tank in the loft with any hassle that might ensue from that.

There is a fairly basic guide here

http://www.cus.net/gas/subcats/gasheating.html

I think it's worth clarifying that non-vented systems need an annual inspection...

Non-vented systems have hot water stored under pressure in a pressure vessel and as a result they require annual safety inspection and certification and the ongoing cost of this should be factored in to your running costs

Bollards

Hmmm, I'm a little confused with this pressure vessel thing. Would this mean that my current hot water tank becomes the pressure vessel and one of the tanks which is in my loft would become redundant? There are two tanks up there, one which stores cold water and one which is something to do with the heating. Also, would it mean that I would have to bleed the radiators less?
So many questions!!!!!

amtrakuk

I too had a revenheat combi boiler.. Like you say not to reliable. The heat exchanger went in mine and it was not covered by British Gas Homecare.

I had to make a choice. A replacement combi to a similar spec would cost (including installation and commissioning) would cost between 2.5k to 4k! That and my gas bill was up at 75.00 a month was why I ditched gas and went electric. At least no more 12.00/month for homecare, rising gas bills and boiler depreciation.

One thing I was shocked on was alot of the newer boilers have more electronics in them than a computer - it seems that way anyhow. There is alot of sensors and safety devices inside them to go wrong. I was advised when I got my quote to go for a boiler of £1k upwards as the cheaper boilers are "cheap Japanese imports" and will only last about 5 years. I was however advised with Worcester Bosch at 1.5k as they will last about 10 years.

amtrakuk

A pressure vessel is a "football" shaped sphere ont he cold water inlet to allow expansion from hot water. This should help you http://www.plumbingpages.com/featurepages/HWunvented.cfm

A

mute_posting

Bollards wrote: »

Hmmm, I'm a little confused with this pressure vessel thing. Would this mean that my current hot water tank becomes the pressure vessel

Definitely not!

Your current cylinder will probably not be designed to be pressurised
MP

bobmedley

mute_posting wrote: »

I think it's worth clarifying that non-vented systems need an annual inspection...

Very early ones did, but modern ones don't. Mine dates from 1999 & does not need an annual inspection.:D

mute_posting

bobmedley wrote: »

Very early ones did, but modern ones don't. Mine dates from 1999 & does not need an annual inspection.:D

Then either you don't have a non-vented system (it is possible to have a VENTED mains pressure system, mine is a gledhill pulsacoil) or AFAIK you have been miss-informed - non-vented mains pressure is notifiable and requires an annual inspection of the safety valve..

MP

EDIT

This may explain it more clearly...

Unvented Mains Pressure Systems
In an unvented system you will be storing a large volume of hot water under pressure. For reasons of safety such systems must be installed by qualified technicians with relevant experience, CITB training and G3 certification.
As a precaution, pressure-relief pipework and valves must be installed to protect against unsafe pressure build-up within the vessel which could result in explosion.
Your Local Authority (Building Control Dept) will need to be advised of your intention to install an unvented system.
For reasons of safety, your system will require annual maintenance to ensure safety equipment is functioning correctly (BS2870).
An unvented system must be commissioned and certified by the installer.

Vented Mains Pressure Systems
A vented system does not store a large volume of hot water under pressure. The Thermal Store, whilst containing hot water, remains at atmospheric pressure.
There are no hazardous issues with a vented system. Pressure relief valves and pipework are not therefore required.
Vented systems do not require Building Control approval.
Because of the simplicity and safety of such systems, installers do not need certification or specialist training.
Vented systems do not need certification.
There are no special annual maintenance requirements.