www.qpsltd.co.nz/pdf/hot_water_cylinder.pdf

I didn't know of the existence of this system - a hwc fed from a
pressure regulator and an open vent pipe. So simple, so cheap and no
loft tank.

On 24/01/2012 22:28, wrote:
www.qpsltd.co.nz/pdf/hot_water_cylinder.pdf

I didn't know of the existence of this system - a hwc fed from a
pressure regulator and an open vent pipe. So simple, so cheap and no
loft tank.

I can't see how that works. Where does the expansion go - it can't go
back into the mains?!
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

Roger Mills wrote:
On 24/01/2012 22:28, wrote:
www.qpsltd.co.nz/pdf/hot_water_cylinder.pdf

I didn't know of the existence of this system - a hwc fed from a
pressure regulator and an open vent pipe. So simple, so cheap and no
loft tank.

I can't see how that works. Where does the expansion go - it can't go back into the mains?!

Expands up the overflow surely?

I suspect UK regulations probably explicitly forbid such an arrangement
which is why you don't see it in this country.

Tim

On Jan 25, 5:17*pm, Roger Mills wrote:

I can't see how that works. Where does the expansion go - it can't go
back into the mains?!

It could go up the mains if there wasn't anything that acted like a
NRV, but it probably just spills out of the OV pipe. The expansion
vessel on unvented water heaters of 50 litres is a requirement of the
UK Water Regulations, most other countries permit the expanding water
to open the pressure relief valve and run to drain. The systems
operate reliably like that. Spillage from the OV is probably allowed.
There's nothing shown in the NZ systems that isn't available n the Uk,
it isn't used because of the UK regulations. The UK spec equipment has
better standard of controls, IMHO.

On Jan 25, 5:17*pm, Roger Mills wrote:
On 24/01/2012 22:28, wrote:

www.qpsltd.co.nz/pdf/hot_water_cylinder.pdf

I didn't know of the existence of this system - a hwc fed from a
pressure regulator and an open vent pipe. So simple, so cheap and no
loft tank.

I can't see how that works. Where does the expansion go - it can't go
back into the mains?!
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

I couldn't get the link to work initially.

I can only assume that the pressure reducing valve is tuned to match
the height of the vent pipe, such that when the system is hot the vent
pipe is near enough full. The relief valve system seems to indicate
this too.

On the basis that I live in a single storey house with poor HW
pressure such a system is interesting, though I think I would retain
the cold water tank for toilet flushing, etc.

Just how far away from regulations in this country is this ?

Rob

wrote in message
...
www.qpsltd.co.nz/pdf/hot_water_cylinder.pdf

I didn't know of the existence of this system - a hwc fed from a
pressure regulator and an open vent pipe. So simple, so cheap and no
loft tank.

It's a primitive unvented cylinder. What they are saying is that it can be
vented if the OV pipe is high enough - all you do is set the pressure
reducing valve to less than the head from the raised pipe.

In a flat I once owned, the tank on the roof gave me 1.5 bar. There was a 1"
pipe from the roof tank to each flat. Most used this pipe to supply a break
tank in each flat and having to use power shower pumps. I got myself a
cylinder that took over 2 bar pressure. There was already two tees off the
1" drop pipe from the tank, in my flat. I took the bottom to the cold feed
of the cylinder and the vent pipe to the top tee. Expansion would be back up
the cold feed - it never got warm in the 1" drop pipe. I could not run a
pipe up to the roof tank for the vent. I also put in a pressure relief valve
set to 2 bar on the cylinder as a backup.

On Jan 25, 6:45*pm, "Doctor Drivel"
wrote:

It's a primitive UNVENTED cylinder. What they are saying *is that it can be
vented if the OV (OPEN VENT) pipe is high enough - all you do is set the pressure
reducing valve to less than the head from the raised pipe.

The presence of an open vent pipe would suggest to most people that it
is not an unvented cylinder.

Ignore all other drivellings.

"robgraham" wrote in message
...
On Jan 25, 5:17 pm, Roger Mills wrote:
On 24/01/2012 22:28, wrote:

www.qpsltd.co.nz/pdf/hot_water_cylinder.pdf

I didn't know of the existence of this system - a hwc fed from a
pressure regulator and an open vent pipe. So simple, so cheap and no
loft tank.

I can't see how that works. Where does the expansion go - it can't go
back into the mains?!
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

I couldn't get the link to work initially.

I can only assume that the pressure reducing valve is tuned to match
the height of the vent pipe, such that when the system is hot the vent
pipe is near enough full. The relief valve system seems to indicate
this too.

On the basis that I live in a single storey house with poor HW
pressure such a system is interesting, though I think I would retain
the cold water tank for toilet flushing, etc.

Just how far away from regulations in this country is this ?


I see no reason why the vented system is outside of UK regs. If say you were
in a ground floor flat and you could run a pipe up say a disused chimney
stack and take it back down again with a U at the top, and out to atmosphere
at he bottom or to a tundish using a HepVo trap to the drains, then I see no
problems with it. You could feed plastic pipe up the flue to say 1 bar (30
foot). The vent pipe needs to contain all expansion, so maybe starting with
22mm then to 28mm at the top and 22mm on the drop

Say if the PRV was set to 1 bar as water is drawn-off the valve will act as
regulator as well - opening if the pressure inside the cylinder drops from 1
bar.

"Onetap" wrote in message
...
On Jan 25, 6:45 pm, "Doctor Drivel"
wrote:

It's a primitive UNVENTED cylinder. What they are saying is that it can be
vented if the OV (OPEN VENT) pipe is high enough - all you do is set the
pressure
reducing valve to less than the head from the raised pipe.

The presence of an open vent pipe would suggest to most people that it
is not an unvented cylinder.


knobhead read what I wrote.

"robgraham" wrote in message
...
On Jan 25, 5:17 pm, Roger Mills wrote:
On 24/01/2012 22:28, wrote:

www.qpsltd.co.nz/pdf/hot_water_cylinder.pdf

I didn't know of the existence of this system - a hwc fed from a
pressure regulator and an open vent pipe. So simple, so cheap and no
loft tank.

I can't see how that works. Where does the expansion go - it can't go
back into the mains?!
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

I couldn't get the link to work initially.

I can only assume that the pressure reducing valve is tuned to match
the height of the vent pipe, such that when the system is hot the vent
pipe is near enough full. The relief valve system seems to indicate
this too.

On the basis that I live in a single storey house with poor HW
pressure such a system is interesting, though I think I would retain
the cold water tank for toilet flushing, etc.

Just how far away from regulations in this country is this ?


The tank in loft system on page 2 has the OV going over the roof tiles. We
do not have that any longer in the UK due to freezing. Maybe this is fine
in the warm North Island of NZ.

On 25/01/2012 17:55, robgraham wrote:

On the basis that I live in a single storey house with poor HW
pressure such a system is interesting, though I think I would retain
the cold water tank for toilet flushing, etc.

You'd have to find somewhere for the vertical vent pipe to go a lot
higher than your existing tank if you were to get a worthwhile pressure
increase. Erect a flag pole, and strap it to that?

It still sounds daft to me, peeing water out of the vent pipe every time
you heat the cylinder. If 30 gallons expands by 2%, you've got to lose
0.6 gallons somewhere. That's more than enough to fill the vent pipe -
and the pipe isn't going to start empty, anyway.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On Jan 25, 7:01*pm, "Doctor Drivel"
wrote:

knobhead read what I wrote.

I did, Drivel.

You wrote...

It's a primitive UNVENTED cylinder........it can be
vented if the OV pipe is high enough.

You're saying it is an unvented vented cylinder.

I'm saying you're the knobhead.
Wibble.

On Jan 25, 7:00*pm, "Doctor Drivel"
wrote:

Just how far away from regulations in this country is this ?

You could probably make it legal in the UK; I think the Water
Regulation requirements to prevent back-siphonage would be an
obstacle. I doubt that the external OV would be allowed, you'd
probably be required to have an internal tundish to indicate a
malfunction of the reducing valve, again as with unvented.

I really don't see the point though. You have many of the
complications of an unvented system in the water inlet group (Pressure
reducing valve, non return valve), but not the benefit of higher-
pressure hot water.

On Jan 25, 8:04*pm, Onetap wrote:
On Jan 25, 7:01*pm, "Doctor Drivel"
wrote:

knobhead read what I wrote.

I did, *Drivel.

You wrote...

It's a primitive UNVENTED cylinder........it can be
vented if the OV pipe is high enough.

You're saying it is an unvented vented cylinder.

* I'm saying you're the knobhead.
Wibble.

With the danger of this becoming a string of abusive posts, your
comment, Onetap, is pedantic and nit-picking on words.

Rob

Doctor Drivel wrote:

wrote in message
...
www.qpsltd.co.nz/pdf/hot_water_cylinder.pdf

I didn't know of the existence of this system - a hwc fed from a
pressure regulator and an open vent pipe. So simple, so cheap and no
loft tank.

It's a primitive unvented cylinder. What they are saying is that it can be
vented if the OV pipe is high enough - all you do is set the pressure
reducing valve to less than the head from the raised pipe.

FWIW, where I lived in NZ, the hot water cylinder was in the basement
and the overflow pipe stuck out of the roof by a metre or so. If I
was to test my failing memory, I'd guess there could have easily been
4-5m of pipe straight up.

#Paul

On Jan 25, 9:15*pm, robgraham wrote:

With the danger of this becoming a string of abusive posts, your
comment, Onetap, is pedantic and nit-picking on words.

You're entitled to your opinion, as I am to mine.
My opinion is that Drivel is an idiot and that his usual self-
indulgent crayoning over this thread is intended solely to give the
impression that he has some expertise in the area.

It might help if you read the first couple of posts and then see
which of the replies have given information as to why this system is
permissible in NZ, but not in the UK. One of the posters has the G3
unvented ticket and might know a little about unvented water heaters;
can you guess which one?

Are you a Drivel sock puppet?

An primitive unvented vented water heater with an open vent? Really?
What did that statement tell you.

It won't turn into a string of abusive posts, I usually manage to
ignore Drivel's inanities. I shall endeavour to apply the same
restraint to your posts.

"Onetap" wrote in message
...
On Jan 25, 7:00 pm, "Doctor Drivel"
wrote:

Just how far away from regulations in this country is this ?

You could probably make it legal in the UK; I think the Water
Regulation requirements to prevent back-siphonage would be an
obstacle. I doubt that the external OV would be allowed, you'd
probably be required to have an internal tundish to indicate a
malfunction of the reducing valve, again as with unvented.

I really don't see the point though. You have many of the
complications of an unvented system in the water inlet group (Pressure
reducing valve, non return valve), but not the benefit of higher-
pressure hot water.


But you do not have all the expensive pressure controls of unvented and the
annual service...and no "Explosions" as it is vented.

"Onetap" wrote in message
...
On Jan 25, 7:01 pm, "Doctor Drivel"
wrote:

knobhead read what I wrote.

I did, Drivel.

You wrote...

It's a primitive UNVENTED cylinder........it can be
vented if the OV pipe is high enough.

You're saying it is an unvented vented cylinder.


Knobhead, Read again!!!

On Jan 25, 11:35*pm, "Doctor Drivel"
wrote:

But you do not have all the expensive pressure controls of unvented and the
annual service...and no "Explosions" as it is vented.

Until the external open vent freezes, when it becomes unvented,
although without the pressure relief valve and the T&P relief valve
you'd find on a BBA-certified unvented water heater.

On Jan 25, 11:37*pm, "Doctor Drivel"
wrote:
"Onetap" wrote in message

...
On Jan 25, 7:01 pm, "Doctor Drivel"
wrote:

knobhead read what I wrote.

I did, *Drivel.

You wrote...

It's a primitive UNVENTED cylinder........it can be
vented if the OV pipe is high enough.

You're saying it is an unvented vented cylinder.


Knobhead, Read again!!!

Wibble.

You're still saying it is an unvented vented cylinder.

Doctor Drivel :

"Onetap" wrote in message news:ce39eb93-d57a-
...
On Jan 25, 7:00 pm, "Doctor Drivel"
wrote:

Just how far away from regulations in this country is this ?

You could probably make it legal in the UK; I think the Water
Regulation requirements to prevent back-siphonage would be an
obstacle. I doubt that the external OV would be allowed, you'd
probably be required to have an internal tundish to indicate a
malfunction of the reducing valve, again as with unvented.

I really don't see the point though. You have many of the
complications of an unvented system in the water inlet group (Pressure
reducing valve, non return valve), but not the benefit of higher-
pressure hot water.


But you do not have all the expensive pressure controls of unvented and
the annual service...and no "Explosions" as it is vented.

Is there any chance you could quote previous messages properly using a
"" prefix on each line? It's time-consuming for me to start reading a
message, realise that I've already read it, then scan down the message
looking for where the response really starts. I'm sure I'm not the only
one who would thank you for doing it properly.

--
Mike Barnes

"Onetap" wrote in message
...
On Jan 25, 11:35 pm, "Doctor Drivel"
wrote:

But you do not have all the expensive pressure controls of unvented and
the
annual service...and no "Explosions" as it is vented.

Until the external open vent freezes, when it becomes unvented,
although without the pressure relief valve and the T&P relief valve
you'd find on a BBA-certified unvented water heater.


Read my others posts about running the pipe vertical "inside". Open vents
cannot terminate outside in the UK any longer because of freezing. They
were a common site on roofs. If it can be run "inside", like up a disused
chimney stack, then this open vented version using mains pressure water is
permissible.

"Mike Barnes" wrote in message
...
Doctor Drivel :

"Onetap" wrote in message news:ce39eb93-d57a-
...
On Jan 25, 7:00 pm, "Doctor Drivel"
wrote:

Just how far away from regulations in this country is this ?

You could probably make it legal in the UK; I think the Water
Regulation requirements to prevent back-siphonage would be an
obstacle. I doubt that the external OV would be allowed, you'd
probably be required to have an internal tundish to indicate a
malfunction of the reducing valve, again as with unvented.

I really don't see the point though. You have many of the
complications of an unvented system in the water inlet group (Pressure
reducing valve, non return valve), but not the benefit of higher-
pressure hot water.


But you do not have all the expensive pressure controls of unvented and
the annual service...and no "Explosions" as it is vented.

Is there any chance you could quote previous messages properly using a
"" prefix on each line? It's time-consuming for me to start reading a
message, realise that I've already read it, then scan down the message
looking for where the response really starts. I'm sure I'm not the only
one who would thank you for doing it properly.

It would be nice if people didn't use google groups as this omits the ""

"Onetap" wrote in message
...
On Jan 25, 11:37 pm, "Doctor Drivel"
wrote:
"Onetap" wrote in message

...
On Jan 25, 7:01 pm, "Doctor Drivel"
wrote:

knobhead read what I wrote.

I did, Drivel.

You wrote...

It's a primitive UNVENTED cylinder........it can be
vented if the OV pipe is high enough.

You're saying it is an unvented vented cylinder.


Knobhead, Read again!!!

Wibble.

You're still saying it is an unvented vented cylinder.


Knob, read again, I am not. I am saying it can be both.

"robgraham" wrote in message
...
On Jan 25, 5:17 pm, Roger Mills wrote:
On 24/01/2012 22:28, wrote:

www.qpsltd.co.nz/pdf/hot_water_cylinder.pdf

I didn't know of the existence of this system - a hwc fed from a
pressure regulator and an open vent pipe. So simple, so cheap and no
loft tank.

I can't see how that works. Where does the expansion go - it can't go
back into the mains?!
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

I couldn't get the link to work initially.

I can only assume that the pressure reducing valve is tuned to match
the height of the vent pipe, such that when the system is hot the vent
pipe is near enough full. The relief valve system seems to indicate
this too.

On the basis that I live in a single storey house with poor HW
pressure such a system is interesting, though I think I would retain
the cold water tank for toilet flushing, etc.
___________________

If you are retaining the tank then there is no point in using this system,
which the prime aim is eliminating the loft tank in the vented version.

BTW, many people in the south of England when renovating, would go to France
and pick up a load of building materials as it was cheaper. Many would
unknowlingly fit in the French unvented cylinders, which pass a small amount
of water into the drains because they had no pressure vessel - like a
Megaflow when the air cushion dissolves, and the householder does nothing to
reinstate the air cushion, which is quite common.

"robgraham" wrote in message
...
On Jan 25, 5:17 pm, Roger Mills wrote:
On 24/01/2012 22:28, wrote:

www.qpsltd.co.nz/pdf/hot_water_cylinder.pdf

I didn't know of the existence of this system - a hwc fed from a
pressure regulator and an open vent pipe. So simple, so cheap and no
loft tank.

I can't see how that works. Where does the expansion go - it can't go
back into the mains?!
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

I couldn't get the link to work initially.

I can only assume that the pressure reducing valve is tuned to match
the height of the vent pipe, such that when the system is hot the vent
pipe is near enough full. The relief valve system seems to indicate
this too.

On the basis that I live in a single storey house with poor HW
pressure such a system is interesting, though I think I would retain
the cold water tank for toilet flushing, etc.

Just how far away from regulations in this country is this ?

Rob

What happens when the water in the vent pipe freezes?
(It projects above the roof)

On Jan 26, 8:19*am, "Doctor Drivel"
wrote:

It would be nice if people didn't use google groups as this omits the ""

It prefixes quoted text fine (as in this post).

Mathew

"Doctor Drivel" wrote in message
...

"Mike Barnes" wrote in message
...
Doctor Drivel :

"Onetap" wrote in message news:ce39eb93-d57a-
...
On Jan 25, 7:00 pm, "Doctor Drivel"
wrote:

Just how far away from regulations in this country is this ?

You could probably make it legal in the UK; I think the Water
Regulation requirements to prevent back-siphonage would be an
obstacle. I doubt that the external OV would be allowed, you'd
probably be required to have an internal tundish to indicate a
malfunction of the reducing valve, again as with unvented.

I really don't see the point though. You have many of the
complications of an unvented system in the water inlet group (Pressure
reducing valve, non return valve), but not the benefit of higher-
pressure hot water.


But you do not have all the expensive pressure controls of unvented and
the annual service...and no "Explosions" as it is vented.

Is there any chance you could quote previous messages properly using a
"" prefix on each line? It's time-consuming for me to start reading a
message, realise that I've already read it, then scan down the message
looking for where the response really starts. I'm sure I'm not the only
one who would thank you for doing it properly.

It would be nice if people didn't use google groups as this omits the ""

No it doesn't.

"Doctor Drivel" wrote in message
...

wrote in message
...
www.qpsltd.co.nz/pdf/hot_water_cylinder.pdf

I didn't know of the existence of this system - a hwc fed from a
pressure regulator and an open vent pipe. So simple, so cheap and no
loft tank.

It's a primitive unvented cylinder. What they are saying is that it can
be vented if the OV pipe is high enough - all you do is set the pressure
reducing valve to less than the head from the raised pipe.

In a flat I once owned, the tank on the roof gave me 1.5 bar. There was a
1" pipe from the roof tank to each flat. Most used this pipe to supply a
break tank in each flat and having to use power shower pumps. I got
myself a cylinder that took over 2 bar pressure. There was already two
tees off the 1" drop pipe from the tank, in my flat. I took the bottom to
the cold feed of the cylinder and the vent pipe to the top tee. Expansion
would be back up the cold feed - it never got warm in the 1" drop pipe. I
could not run a pipe up to the roof tank for the vent. I also put in a
pressure relief valve set to 2 bar on the cylinder as a backup.


I think with that sytem you would be giving hot water to other flat
dwellers.
Of course the1"pipe never got hot. The hot (expansion) water was conducted
away to other places.

Also, when you drew hot water off, you would also get cold mixed in

On Jan 26, 8:20*am, "Doctor Drivel"
wrote:
"Onetap" wrote in message

...
On Jan 25, 11:37 pm, "Doctor Drivel"
wrote:





"Onetap" wrote in message

....
On Jan 25, 7:01 pm, "Doctor Drivel"
wrote:

knobhead read what I wrote.

I did, Drivel.

You wrote...

It's a primitive UNVENTED cylinder........it can be
vented if the OV pipe is high enough.

You're saying it is an unvented vented cylinder.


Knobhead, Read again!!!

Wibble.

You're still *saying it is an unvented vented cylinder.


Knob, read again, I am not. *I am saying it can be both.

You say it can be both.

I say it is intended solely for use as a vented cylinder.
If it were intended to be used as an unvented cylinder it would
require additional safety devices (PRV, T&PRV), additional safety
cutouts on all the heat inputs and a means of accomodating the
expansion to achieve BBA certification. This would probably double the
cost of the bare cylinder.

BTW, any water hammer, caused by washing machine valves or quarter
turn taps, would probably cause a spurt of water from the external
open vent.

IMHO it seems cheap and primitive.

Doctor Drivel :

"Mike Barnes" wrote in message news:NqMpEhx
...
Doctor Drivel :

"Onetap" wrote in message news:ce39eb93-d57a-
...
On Jan 25, 7:00 pm, "Doctor Drivel"
wrote:

Just how far away from regulations in this country is this ?

You could probably make it legal in the UK; I think the Water
Regulation requirements to prevent back-siphonage would be an
obstacle. I doubt that the external OV would be allowed, you'd
probably be required to have an internal tundish to indicate a
malfunction of the reducing valve, again as with unvented.

I really don't see the point though. You have many of the
complications of an unvented system in the water inlet group (Pressure
reducing valve, non return valve), but not the benefit of higher-
pressure hot water.


But you do not have all the expensive pressure controls of unvented and
the annual service...and no "Explosions" as it is vented.

Is there any chance you could quote previous messages properly using a
"" prefix on each line? It's time-consuming for me to start reading a
message, realise that I've already read it, then scan down the message
looking for where the response really starts. I'm sure I'm not the only
one who would thank you for doing it properly.

It would be nice if people didn't use google groups as this omits the
""

It's *you* that's omitting the "". The headers indicate that you're
using Microsoft Outlook Express, not GG.

--
Mike Barnes

On Jan 26, 5:12*pm, Mike Barnes wrote:
Doctor Drivel :

It's *you* that's omitting the "".

He's a troll, with much previous form.
If it annoys you, he'll do it all the more. It gives him some
gratification. Killfile him.

"Tim" wrote in message
...
Roger Mills wrote:
On 24/01/2012 22:28, wrote:
www.qpsltd.co.nz/pdf/hot_water_cylinder.pdf

I didn't know of the existence of this system - a hwc fed from a
pressure regulator and an open vent pipe. So simple, so cheap and no
loft tank.

I can't see how that works. Where does the expansion go - it can't go
back into the mains?!

Expands up the overflow surely?

I suspect UK regulations probably explicitly forbid such an arrangement
which is why you don't see it in this country.

There is nothing wrong with the vented version as long as the OV is freeze
proof.

"Onetap" wrote in message
...
On Jan 26, 5:12 pm, Mike Barnes wrote:
Doctor Drivel :

It's *you* that's omitting the "".

He's a troll, with much previous form.


You are an idiotic knobhead who can't read.

"Onetap" wrote in message
...
On Jan 26, 8:20 am, "Doctor Drivel"
wrote:
"Onetap" wrote in message

...
On Jan 25, 11:37 pm, "Doctor Drivel"
wrote:





"Onetap" wrote in message

...
On Jan 25, 7:01 pm, "Doctor Drivel"
wrote:

knobhead read what I wrote.

I did, Drivel.

You wrote...

It's a primitive UNVENTED cylinder........it can be
vented if the OV pipe is high enough.

You're saying it is an unvented vented cylinder.


Knobhead, Read again!!!

Wibble.

You're still saying it is an unvented vented cylinder.


Knob, read again, I am not. I am saying it can be both.

You say it can be both.


So does the link.


I say it is intended solely for use as a vented cylinder.


Not according to the link.

snip drivel

"harryagain" wrote in message
...

"Doctor Drivel" wrote in message
...

wrote in message
...
www.qpsltd.co.nz/pdf/hot_water_cylinder.pdf

I didn't know of the existence of this system - a hwc fed from a
pressure regulator and an open vent pipe. So simple, so cheap and no
loft tank.

It's a primitive unvented cylinder. What they are saying is that it can
be vented if the OV pipe is high enough - all you do is set the pressure
reducing valve to less than the head from the raised pipe.

In a flat I once owned, the tank on the roof gave me 1.5 bar. There was a
1" pipe from the roof tank to each flat. Most used this pipe to supply a
break tank in each flat and having to use power shower pumps. I got
myself a cylinder that took over 2 bar pressure. There was already two
tees off the 1" drop pipe from the tank, in my flat. I took the bottom to
the cold feed of the cylinder and the vent pipe to the top tee. Expansion
would be back up the cold feed - it never got warm in the 1" drop pipe.
I could not run a pipe up to the roof tank for the vent. I also put in a
pressure relief valve set to 2 bar on the cylinder as a backup.


I think with that sytem you would be giving hot water to other flat
dwellers.

I never.

Of course the1"pipe never got hot. The hot (expansion) water was conducted
away to other places.

It wasn't as the 22mm leg from the 28mm drop pipe was long enough.

Also, when you drew hot water off, you would also get cold mixed in

I never, as there was a check valve in both legs.

On Jan 26, 11:21*pm, "Doctor Drivel"
wrote:

There is nothing wrong with the vented version as long as the OV is freeze
proof.

It is open to the air, as the name OPEN VENT suggests.

It would have to be trace heated or completey within the insulated
envelope of the building.

"Onetap" wrote in message
...
On Jan 26, 11:21 pm, "Doctor Drivel"
wrote:

There is nothing wrong with the vented version as long as the OV is
freeze
proof.

It is open to the air, as the name OPEN VENT suggests.

Ten out ten there. Very good.

It would have to be trace heated or
completey within the insulated
envelope of the building.

Or up a disused chimney stack (inside the heat envelope) or us insulated
pipework.

"Doctor Drivel" wrote in message
...

"harryagain" wrote in message
...

"Doctor Drivel" wrote in message
...

wrote in message
...
www.qpsltd.co.nz/pdf/hot_water_cylinder.pdf

I didn't know of the existence of this system - a hwc fed from a
pressure regulator and an open vent pipe. So simple, so cheap and no
loft tank.

It's a primitive unvented cylinder. What they are saying is that it can
be vented if the OV pipe is high enough - all you do is set the pressure
reducing valve to less than the head from the raised pipe.

In a flat I once owned, the tank on the roof gave me 1.5 bar. There was
a 1" pipe from the roof tank to each flat. Most used this pipe to supply
a break tank in each flat and having to use power shower pumps. I got
myself a cylinder that took over 2 bar pressure. There was already two
tees off the 1" drop pipe from the tank, in my flat. I took the bottom
to the cold feed of the cylinder and the vent pipe to the top tee.
Expansion would be back up the cold feed - it never got warm in the 1"
drop pipe. I could not run a pipe up to the roof tank for the vent. I
also put in a pressure relief valve set to 2 bar on the cylinder as a
backup.


I think with that sytem you would be giving hot water to other flat
dwellers.

It never.

Of course the1"pipe never got hot. The hot (expansion) water was
conducted away to other places.

It wasn't as the 22mm leg from the 28mm drop pipe was long enough.

Also, when you drew hot water off, you would also get cold mixed in

It never, as there was a check valve in both legs.

Addition: An anti-vacuum valve was fitted on the cylinder in case. The
cylinder could expand up the open vent, which was the also the cold feed
which was via a vented tank. The cylinder had a pressure relief valve and
an anti-vacuum valve and a high temp limit stat in case the normal stat
failed. It wasn't pressurised.

"Mike Barnes" wrote in message
...
Doctor Drivel :

"Mike Barnes" wrote in message news:NqMpEhx
...
Doctor Drivel :

"Onetap" wrote in message news:ce39eb93-d57a-
...
On Jan 25, 7:00 pm, "Doctor Drivel"
wrote:

Just how far away from regulations in this country is this ?

You could probably make it legal in the UK; I think the Water
Regulation requirements to prevent back-siphonage would be an
obstacle. I doubt that the external OV would be allowed, you'd
probably be required to have an internal tundish to indicate a
malfunction of the reducing valve, again as with unvented.

I really don't see the point though. You have many of the
complications of an unvented system in the water inlet group (Pressure
reducing valve, non return valve), but not the benefit of higher-
pressure hot water.


But you do not have all the expensive pressure controls of unvented and
the annual service...and no "Explosions" as it is vented.

Is there any chance you could quote previous messages properly using a
"" prefix on each line? It's time-consuming for me to start reading a
message, realise that I've already read it, then scan down the message
looking for where the response really starts. I'm sure I'm not the only
one who would thank you for doing it properly.

It would be nice if people didn't use google groups as this omits the
""

It's *you* that's omitting the "". The headers indicate that you're
using Microsoft Outlook Express, not GG.

Google Groups strips off the "" before sending.