Vented / unvented cylinders, pros and cons

[Dan Robinson]

Not mentioned in Lochinvar literature.

 

[Dan Robinson]

Not mentioned in Andrews literature.

 

[PullerGas]

Hmmmm.......we've gone from c.appy boiler manufacturers to the manufacturers of sludge buckets!!

Really BG you need to Google more creditable manufacturers!!

 

[bernardgreen]

Not mentioned in Vaillant literature

Google is your friend ( well it sometimes it is a helpful friend to me ) Much like the librarian in a reference library, a guide to where information, reliable or not, inaccurate or not can be found.

http://www.vaillant.co.uk/downloads/unistor-installation-service-manual-261492.pdf

Installation and maintenance instructions for uniSTOR 0020111105_02
9
i
If a cylinder is fitted very high up in the building,
negative pressure may form in the cylinder.
Under such circumstances, the competent per-
son must decide whether an anti-vacuum valve
is required in order to prevent damage to the
cylinder. If, as a result of draining or thermal
contraction of the drinking water, the negative
pressure in the cylinder is too high, an anti-vac-
uum valve ensures pressure compensation as a
result of air flowing into the cylinder.

I cannot be bothered to see if the other makes you quote do not mention anti vacuum valves

 

[Dan Robinson]

Not in the manuals I have, but fair enough.
There is still a hefty dose of "so what".

 

[shambolic]

6 pages of pish.

 

[PullerGas]

6 pages of pish.

I must refrain from reading these retired 'engineer's' threads. Life is too short & they're complete rsoles!!

It's like dealing with M&E engineers. They have a licence to print money & not a pragmatic bone in their body - complete morons!!

 

[Dan Robinson]

6 pages of pish.

I know, but the M25 was closed and I was stuck in traffic.... It kept me amused.

Thank christ no one mentioned ACV's



Oh.. crap.

 

[bernardgreen]

A pressure regulating valve did fail to control pressure and the results of that failure were the reason for the discussion starting on the other forum.

The discussion was on the merits of unvented versus vented and came about when the designs for houses in a Housing Association new build project of between 70 to 85 houses were being drawn up.

The architects were initially planning on combination boilers and no cylinder to allow them to do away with the airing cupboard, cisterns etc etc.

They then changed to a design with heat only boilers and unvented cylinders as this provided the airing cupboard that was on many of the prospective tenants / part owners wish lists.

The final decision however has been made by the Housing Association. They will not accept combination boilers, they will not accept unvented cylinders.

The Housing Association decision is based on reams of data they have collected relating to reliability, time to repair and intallation costs of the various systems. They also obtained data about the costs, both direct and indirect, incurred by several Housing Associations and co-ownerhip schemes in maintenance and repair over the past ten years. Various different types of heating and hot water systems were used in those schemes with varying costs and reliabilty.

It was failure of a pressure regulating valve feeding an unvented cylinder that raised the concerns in the Housing Association as to the suitability of pressurised cylinders. The pressure relief valve had operated and dumped the over pressure but was then continuously dumping water, at first hot, into an area used by children as a "safe" play area. Not a common problem but considered, with other factors, as reason enough to avoid pressurised cylinders in rented /part ownership domestic new builds..


The data and decisions based on it may not be valid for heating and hot water systems in owner occupied homes where the owner's incentive to maintain the system may be higher than the incentive a tenant / part owner may have. An owner occupier is more likely to arrange a preventitive repair / service at the first sign of a problem where a tenant / part owner may not report the problem to the Housing Association until the system has totally failed. The Housing Association then has to arrange for emergency repairs at higher cost.

 

[Dan Robinson]

So a null argument again! FFS.

So a housing association can't guarantee to install and maintain the system properly, therefore you conclude it is an inferior system. You also ignore the down sides of open vented as you are totally blinkered despite the BS alternative thinker label you like to apply to yourself.


As the other thread got locked due to whiny Google warriors complaining to the mods, I should like to point out that you recently advocated using fairy liquid to find gas leaks. And you claim to not have given dangerous advice in the past.



Housing associations

 

[bernardgreen]

I should like to point out that you recently advocated using fairy liquid to find gas leaks.

I would like to point out that the context was NOT an RGI working to his or her training but a house owner concerned that gas might be leaking in small quantities from a recently removed bayonent coupling A bubble test would give peace of mind or alert to the need to get the pipe selaed properly.

Housing associations

For some people Housing associations and co-ownership schemes are the only way to get a decent place to live. And not all schemes are poor quality. One such scheme is

http://www.c20society.org.uk/botm/walters-way-lewisham/

there are many others, some with houses in the top 25% of local price ranges.

So a housing association can't guarantee to install and maintain the system properly, therefore you conclude it is an inferior system.

The quality of the installation would depend on the quality of the installer. You seem to ignore the difference in cost of maintaining the different systems. No one has said the un-vented system is inferior or superior in terms of function. What the unvented cylinder requires is a higher level of maintainance for any repairs ( ie has to be a G3 technician ) when a vented system can be repaired by any competent person with basic plumbing skills.

The Housing Association did seek advice from the technical departments of ( at least ) two manufacturers of heating systems. Both advised against combi boilers for the houses and were 50 / 50 about vented or unvented.

 

[Dan Robinson]

No one has said the un-vented system is inferior

Then why bring up the subject in the first place? Oh wait - you want to get on your high horse and pontificate about things.

For some people Housing associations and co-ownership schemes are the only way to get a decent place

Did I say otherwise?

I would like to point out that the context was NOT an RGI working to his or her training but a house owner

Oh, thats OK then. FFS

 

[Dan Robinson]

I wonder how much chlorinating a cold water cistern would cost in relation to an anti-legionella cycle?

Oh wait - you have not once responded to the maintenance that should be carried out on a open vented system.

 

[bernardgreen]

Dan

You have your opinions. You and your customers are welcome to them.

End of

 

[Dan Robinson]

And you have your opinions. Based largely on poorly founded assumptions and misunderstanding things google throws up. As for the rest of your sources..... well....