Hi, I have another query with regard to my own plumbing this time that
I would like some advice on please. We are building an extension at
the moment and need to run water from the current house into the
extension. Without going into all the reasons why, I am considering
upgrading the gravity fed hot water cylinder to a pressurised one.

The cost of these cylinders in the UK seems over the top, but a friend
recently told me they were much cheaper in France & he had a recent
Brico Depot catalogue to hand. A 150 ltr cylinder costs 99 Euros
fitted with a 1800w immersion heater, a 200 ltr is even cheaper at 90
Euros! I understand that these do not have a coil inside them so I
could not hook it up to my existing C/H system. This does not bother
me, it does not seem to cost much more whether I heat off gas or
electric from past experience. According to him, you just plumb them
in, connect the water pipes up and away you go.

Has anyone any experience of fitting these things & can offer any
advice?

My questions a

Will these tanks fit up to my existing 22mm plumbing connections OK ?

Can anyone forsee any problems modifying my C/H system as the pipes
won't go through the HW cylinder any longer ?

Would I be breaking any regulations and/or should the building
inspector be involved ?

Do I have to fit a vent pipe (think I do)?

Can anyone forsee any other problems ?

Thanks,

Peter

Would I be breaking any regulations and/or should the building
inspector be involved ?

I would be very surprised if it is legal. The building regulations are very
strict about the safety controls of these devices. In the rest of the world,
where they've been used for decades, the regulations are much more lax,
although I suppose there could be a European trade directive saying that if
they're legal in France, they have to be accepted here.

Do I have to fit a vent pipe (think I do)?

That would make it an unpressurised cylinder and, therefore, would almost
certainly make it legal, but it would require a header tank and not provide
mains hot water.

Christian.

Christian McArdle wrote:
Would I be breaking any regulations and/or should the building
inspector be involved ?

I would be very surprised if it is legal. The building regulations are very
strict about the safety controls of these devices. In the rest of the world,
where they've been used for decades, the regulations are much more lax,
although I suppose there could be a European trade directive saying that if
they're legal in France, they have to be accepted here.

I suspect that this may well be true, certainly that is the ultimate
aim. It has been found (see threads here a while ago) that a house
wired to UK standards and with UK sockets etc. is OK in Spain.

--
Chris Green

Christian McArdle wrote:

Would I be breaking any regulations and/or should the building
inspector be involved ?


I would be very surprised if it is legal. The building regulations are very
strict about the safety controls of these devices. In the rest of the world,
where they've been used for decades, the regulations are much more lax,
although I suppose there could be a European trade directive saying that if
they're legal in France, they have to be accepted here.


Do I have to fit a vent pipe (think I do)?


That would make it an unpressurised cylinder and, therefore, would almost
certainly make it legal, but it would require a header tank and not provide
mains hot water.

Er. not so. There should be a a vent pipe coupled to a pressure valve.

They 'blow off' at about 2 bar I thnk.


Christian.

That would make it an unpressurised cylinder and, therefore, would
almost certainly make it legal, but it would require a header tank
and not provide mains hot water.

Er. not so. There should be a a vent pipe coupled to a pressure valve.

Well, I would call that a pressure relief pipe, not a vent, but it's only a
matter of nomenclature.

After all, they are called "unvented" cylinders, which sort of implies there
is no vent.

Christian.

"Peter Cherry" wrote in message
m...

Hi, I have another query with regard to my own plumbing this time that
I would like some advice on please. We are building an extension at
the moment and need to run water from the current house into the
extension. Without going into all the reasons why, I am considering
upgrading the gravity fed hot water cylinder to a pressurised one.

The cost of these cylinders in the UK seems over the top, but a friend
recently told me they were much cheaper in France & he had a recent
Brico Depot catalogue to hand. A 150 ltr cylinder costs 99 Euros
fitted with a 1800w immersion heater, a 200 ltr is even cheaper at 90
Euros! I understand that these do not have a coil inside them so I
could not hook it up to my existing C/H system. This does not bother
me, it does not seem to cost much more whether I heat off gas or
electric from past experience.

What! Gas is 3 to 4 times cheaper than electricity per kW. You haven't
looked at your bills closely enough.

According to him, you just plumb them
in, connect the water pipes up and away you go.

Has anyone any experience of fitting these things & can offer any
advice?

My questions a

Will these tanks fit up to my existing 22mm plumbing connections OK ?

If not adaptors are available from continental sizes to ours. The French
use BSP sizes for threads

Can anyone forsee any problems modifying my C/H system as the pipes
won't go through the HW cylinder any longer ?

Would I be breaking any regulations and/or should the building
inspector be involved ?

A BBA approved installer has to fit an unvented cylidner. You can't do it
yourself.

Do I have to fit a vent pipe (think I do)?

No. a 1" over flow pipe with tundish on it.

Can anyone forsee any other problems ?

Britiush unvented cylidner have more safety protectiopn on them than
continental versions.

An unvented system consists of:

- Expansion vessel. An external pressure vessel or internal pressure air
pocket.
- A high-pressure relief valve. If pressure exceeds the set limit the valve
opens releasing pressure to a safe level.
- A high-temperature relief valve. If high temperatures occur, typically
90-95C, the valve opens to amtosphere..
- Non-return valve. To prevent cylinder implosions and back-pressure into
the cold mains supply pipe.
- Pressure reducing valve. To reduce the inlet pressure to a working
pressure of typically 2 bar for copper and 3.5 bar for steel cylinders.

If it doesn't have the above it will not conform to UK specs and be illegal.

Have you tried looking at a thermal store, as you can DIY these. There are
some cheapish ones about.

"IMM" wrote in message
...

"Peter Cherry" wrote in message
m...

Hi, I have another query with regard to my own plumbing this time that
I would like some advice on please. We are building an extension at
the moment and need to run water from the current house into the
extension. Without going into all the reasons why, I am considering
upgrading the gravity fed hot water cylinder to a pressurised one.

The cost of these cylinders in the UK seems over the top, but a friend
recently told me they were much cheaper in France & he had a recent
Brico Depot catalogue to hand. A 150 ltr cylinder costs 99 Euros
fitted with a 1800w immersion heater, a 200 ltr is even cheaper at 90
Euros! I understand that these do not have a coil inside them so I
could not hook it up to my existing C/H system. This does not bother
me, it does not seem to cost much more whether I heat off gas or
electric from past experience.

What! Gas is 3 to 4 times cheaper than electricity per kW. You haven't
looked at your bills closely enough.

Or his boiler is running at 25% efficiency ! :-)