Not planning to, Richard. The system works perfectly well at present. Yes, it would eliminate the small loft tank but is unlikely to be improved otherwise - and just introduces something else to go wrong. What I do plan to do is fit a magnetic filter.....a Fernox tf1 or similar. That would catch all the minute debris in the system which can't be bad. 10MY (Sept 09) TD4 HSE Auto in Stornoway Grey (Now Gone)

08 FL2 TD4 SE Manual in Rimini Red (Now Gone)

2 further points to consider:

1. Go for a stainless steel cylinder - well worth the extra.
2. Fit a water softener if you live in a hard water area.

I concur with comments above - you are fitting a potential bomb into your property so make sure the plumber/heating engineer has the right ticket. see here: http://www.e-lindsey.gov.uk/NR/rdonlyres/B...ystems.pdf MY 09 GS manual in Lago Grey, Wood Co arm rest and side bumper strips - now sold.

MY 15 SD4 SE Auto Orkney Grey with colour coded Bumper Door Mouldings

Tenet - Yes, a stainless steel cylinder of course! In fact, I am not aware of any readily available copper cylinders for unvented systems. I guess copper is too a soft material to be capable of withstanding the test pressures needed without being extra thick, and therefore expensive! Water softener - we do not live in a noticeably hard water area, but I would need a major redesign to fit one as the main feed splits immediately it enters the building - and it is all buried within the stud walls! Also, as I have said already, plumbers tickets checked as part of the surveys.
Thanks for your input! 10MY (Sept 09) TD4 HSE Auto in Stornoway Grey (Now Gone)

08 FL2 TD4 SE Manual in Rimini Red (Now Gone)

There is a ceramic lined mild steel cylinder that requires an anti corrosion system so be careful. Our original cylinder was this type and failed after about 5 years. We now have an Ariston stainless cylinder and things seem ok (Ihope) MY 09 GS manual in Lago Grey, Wood Co arm rest and side bumper strips - now sold.

MY 15 SD4 SE Auto Orkney Grey with colour coded Bumper Door Mouldings

dunkley201 wrote:

Tenet - Yes, a stainless steel cylinder of course! In fact, I am not aware of any readily available copper cylinders for unvented systems. I guess copper is too a soft material to be capable of withstanding the test pressures needed without being extra thick, and therefore expensive! Water softener - we do not live in a noticeably hard water area, but I would need a major redesign to fit one as the main feed splits immediately it enters the building - and it is all buried within the stud walls! Also, as I have said already, plumbers tickets checked as part of the surveys.
Thanks for your input!

Tenet thanks, I will check the spec of the cylinder(s) recommended. An added complication with our installation is we need a "slimline" type cylinder to fit through the airing cupboard doorway! Limits the choice somewhat!

Archie thanks for the scalemaster suggestion. I guess you are thinking of the Electrolytic or Digisonic versions? 10MY (Sept 09) TD4 HSE Auto in Stornoway Grey (Now Gone)

08 FL2 TD4 SE Manual in Rimini Red (Now Gone)

The scale master is a fit and forget it just stops the limescale from sticking as it alters the properties of it.we now fit them to all our water heaters even though they are supposed to cope with limescale,they are not expensive at around £30=£50
I would post a link but I am not very good with computers sorry/

www.scalemaster.co.uk/scalemaster.pdf‎

Last edited by archie98 on 18th Oct 2013 5:33 pm. Edited 2 times in total

We live in a very hard water area and had a water softener fitted at the same time as installation of the unvented cylinder. Made sense to do it all at the same time given all the new pipe runs needed...including a non-softened CW to the kitchen. http://www.tapworks.co.uk/water-softener-ad11/

With the unvented system prepare to get exfoliated with the water pressure in the shower the first time!

Looks kike I managed it hope it helps you.

Archie - I think this is the link you meant: http://scalemaster.co.uk/products/limescale-inhibitors/ Thanks for your help

Richard - It's a shame I do not have room around the pipework for a ff softener - I would if I could, I assure you! 10MY (Sept 09) TD4 HSE Auto in Stornoway Grey (Now Gone)

08 FL2 TD4 SE Manual in Rimini Red (Now Gone)

At least you know what you are looking at, told you I aint good with these things,for the reference I do have one fitted at home.

I guess you referred to the electrolytic models?

BOB 10MY (Sept 09) TD4 HSE Auto in Stornoway Grey (Now Gone)

08 FL2 TD4 SE Manual in Rimini Red (Now Gone)

Well guys, I thought I would report back now the job is done.
The plumber fitted a RM Stelflow slimline cylinder, converting the DHW system to unvented. He also converted the CH system to unvented. Both expansion vessels were fitted in the top of the airing cupboard. I got him to fit a new pump to the CH as my original 15yr old Grundfoss pump had failed to start a couple of times. I sourced a Wilo Yonos Pico pump (with 5 yr warranty) from Screwfix. Results: The whole CH/DHW system is quieter, rads hotter, endless hot water flowing at Niagra rate! The 15mm cold feed has proven to be well up to the job, although of course it was upgraded to 22mm well before the cylinder.
I fitted a Fernox TF1 Compact filter at the boiler whilst the plumber worked on the tank upstairs. I just have to install a Scalemaster on the cylinder feed pipe as per Archie's suggestion. I can also now fully insulate the loft without the obstruction of any water storage tanks. Very pleased. 10MY (Sept 09) TD4 HSE Auto in Stornoway Grey (Now Gone)

08 FL2 TD4 SE Manual in Rimini Red (Now Gone)

 MY 09 GS manual in Lago Grey, Wood Co arm rest and side bumper strips - now sold.

MY 15 SD4 SE Auto Orkney Grey with colour coded Bumper Door Mouldings