upgrade of gravity/open vent system?

[curious99]

Hi guys,

we have a reasonably well functioning gravity (open vent) system. The only problem is that one of us likes long showers so ideally would like more pressure and definitely more hot water.

We were advised to go for sealed system with larger hot water cylinder or for a combi. But we also were told that to be safe, need to replace all pipes.

As an alternative, we are thinking about getting a bigger hot water cylinder (from 117l to at least 160l, ideally 200l) and installing a pump for shower.

1. What would you do if you were us?
2. Is the sealed system worthy of the hassle of replacing the pipes?
3. How high is the chance that we will need to replace pipes (our flat got converted in the 1980s but we do not know much about the pipework)?
4. Is upgrading the hot water cylinder alone sufficient or do we also need to upgrade the cold water tank as well?

We have two baths/showers which would be good to run simultaneously, but this is not necessary. Our bolier is condensing, and we do not mind upgrading it if needed.

Huge thanks in advance

 

[curious99]

Clarification:

our choice between a) combi (with threat of pipework replaced) b) sealed system (again with threat of pipework replaced) c) exisiting open vent with larger hot water cylinder plus a pump.

Or any other suggestion would be appreciated.

Thanks a lot

 

[45yearsagasman]

Lots of possibilities here. One suggestion is to fit a heat only boiler and keep it open vented and install a mains pressure unvented cylinder to provide good hot water. This would be dependant on a good cold water supply, which should be measured by anyone quoting the job.

 

[curious99]

Dear 45yearsagasman,
if we go for unvented cylinder, would we still need to change the pipes - as the cylinder would then take the mains pressure and thus would require stronger pipes?
Thanks a lot

 

[45yearsagasman]

The heating circuit pipework would be flushed and remain. If your hot water pipework is copper, then I suspect that it would be perfectly OK to accept the higher pressures from the unvented cylinder. 1980's pipework should be OK. Get a second opinion is my further advice as a site visit is the only way to be 100% sure.

 

[curious99]

Oh thank you will definitely get an on-site visit by a specialist