Ok. I know there are countless discussion topics on this (I've read
them!) but I'm after a little confirmation before I go cutting into my
pipework.

I am fitting a new shower to the bathroom with a separate pump. After
much deliberation, I have run a dedicated 22mm cold feed from my CW
cistern in the loft into my airing cupboard on the 1st floor. The twin
input pump is to be placed on the floor in the cupboard alongside the
HW tank. I now need to supply hot water from the HW tank.

Wishing to avoid a Essex / Wessex / Surrey or any fiddling with flanges
on the HW tank, I could T into the 22mm vertical pipe that is the vent
and HW supply for the bath. This `should` be ok. However, it would be
infinitely easier for me to T into the horizontal coming from the HW
tank that connects to the vent pipe / bath supply. If I brought a
downwards pipe from this horizontal to the pump would all be ok or am I
asking for trouble?

Kind regards

Alun

"Big Al" wrote in message
oups.com...
Ok. I know there are countless discussion topics on this (I've read
them!) but I'm after a little confirmation before I go cutting into my
pipework.

I am fitting a new shower to the bathroom with a separate pump. After
much deliberation, I have run a dedicated 22mm cold feed from my CW
cistern in the loft into my airing cupboard on the 1st floor. The twin
input pump is to be placed on the floor in the cupboard alongside the
HW tank. I now need to supply hot water from the HW tank.

Wishing to avoid a Essex / Wessex / Surrey or any fiddling with flanges
on the HW tank, I could T into the 22mm vertical pipe that is the vent
and HW supply for the bath. This `should` be ok. However, it would be
infinitely easier for me to T into the horizontal coming from the HW
tank that connects to the vent pipe / bath supply. If I brought a
downwards pipe from this horizontal to the pump would all be ok or am I
asking for trouble?

Alun, Tee in as close as possible to the hot water cylinder. On the
vertical vent pipe insert a piece of 28mm pipe for as long as you can. When
the pump kicks in it take the line of least resistance. This means that the
water in the open vent pipe is drawn into the pump. If there is enough
water in that pipe then the pump will use this initially (not running dry),
and then take water from the cylinder as the system stabilises after the
initial pump surge.

You should have run 28mm from the cold water tank to the cylinder. As
already have a 22mm pipe, you could take another pipe off the cold water
tank and run this to the cylinder. Two 22mm pipes in parallel. If there is
another connection at the bottom of the cylinder use this. If not then fit
a 28mm cylinder connector and tee the two 22mm pipes into this. have a full
bore stop-cock on each 22mm pipe.

Using a 22mm cylinder cold feed means that when the pumps is running, if hot
water is drawn off elsewhere, it will rob the cylinder and pump of water,
with the pumps taking the line of least resistance and drawing down from the
open vent, then running dry.





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Hi!

Many thanks for the reply. I think I am ok with the feed from the CW
cistern to the HW tank as it is already 28mm. The pipe I have added is
a dedicated 22mm from CW cistern to the pump.

Adding a length of 28mm to the vent pipe should be ok. I guess this
means that there is more water held above the pump and hence the pump
is less likely to suck it all through?

Re - `Tee as close as possible to the HW cylinder`. Does that mean
that there should be no difference teeing into the horizontal section
than there is teeing into the vertical bath / vent pipe?

Alun

"Big Al" wrote in message
ups.com...
Hi!

Many thanks for the reply. I think I am ok with the feed from the CW
cistern to the HW tank as it is already 28mm. The pipe I have added is
a dedicated 22mm from CW cistern to the pump.

Adding a length of 28mm to the vent pipe should be ok. I guess this
means that there is more water held above the pump and hence the pump
is less likely to suck it all through?

Re - `Tee as close as possible to the HW cylinder`. Does that mean
that there should be no difference teeing into the horizontal section
than there is teeing into the vertical bath / vent pipe?

Doesn't matter what size pipe you are using, the pump will suck the water
out the vent pipe and pull air through, using a wider pipe will just delay
the air inrush by a couple of milliseconds.... been there done that.....

Ended up doing "a propper job" with a Warix flange on top of tank after
a*sing around bodging the vent. Did you ever wonder why all the shower pump
fitting instructions say you must use a flange ? well they are right use
flange.

If I was fitting again I would use an Essex flange, fitted/cut into the side
of the tank to save all the messing around and re-routing of the vent pipe
feed with the Warix flange (not the vent comes from the side of the flange
not the top, meaning re-arrangement of vent piping is required). Techflow do
a flange (Techflange) that can easily be retrofitted to a tank.

Anyway with correct flange (and Techflow pump http://www.techflow.co.uk)
shower was wonderful and absolutely no trapped air...

Doesn't matter what size pipe you are using, the pump will suck the water
out the vent pipe and pull air through, using a wider pipe will just delay
the air inrush by a couple of milliseconds.... been there done that.....

Actually, if you get enough water flow into the bottom of the cylinder, you
can get it to work without a flange. I managed with my old system and that
was with an immense flow rate too, (i.e. 50lpm).

The key is not the vent. It is getting water into the bottom of that
cylinder. Short, wide, unshared, flowed bended and with no constricting
valves is the order of the day.

Even with a flange, you'll start sucking air eventually if you don't sort
the cold water supply to the cylinder.

Christian.

Christian McArdle wrote:
Actually, if you get enough water flow into the bottom of the
cylinder, you
can get it to work without a flange. I managed with my old system and
that
was with an immense flow rate too, (i.e. 50lpm).

Hi Christian,
I'm following this thread because of a looming en-suite installation.

In my circumstance, I have a 50 gallon cold cistern in the loft feeding
my hot water cylinder in the floor below (approximately eight feet
down).
Supply is via 28mm copper pipework all the way into the hot water
cylinder,
the route of this supply pipe is "continually rising" or level
sometimes
(what I mean is there are no down-then-ups in the topology).

Out the top of my hot cylinder I plumbed the outlet in 28mm copper,
which
gracefully (45 degree elbow) slopes down to floor level where the
28mm pipework ends in an compression T piece with 22mm pipework either
side.
As my mind pictures a plan view of this setup, the left side of the T
wanders
off in 22mm copper to the bathroom to supply the existing gravity
shower,
bath and basin.
The right side of the T comes along for about two or three feet in 22mm
copper then dives downward to the ground floor.
All this 22mm pipework safely enclosed in the eaves of my upstairs.

New en-suite planned for the right side of the house (existing shower
and
bath at the left gable end of the house but is downstairs). The
en-suite
(obviously) is in the upstairs, off the master bedroom.

Since the eaves is about two feet wide, I'd prefer not to site the new
pump
in the middle of the (guessed) ten metres run of the length of the
house
because it will be a bl**dy nuisance on those ocassions when I have to
crawl
along there to do maintenance.
So I'd like to site my new pump in the eaves but at the right hand
gable end.

Present plan (and this is where I'd be grateful for advice) is to plumb
the descending 28mm pipe from the hot tank such that when it hits the T
piece
and turns RIGHT it will still be in 28mm. Then two feet later as it
turns
down for the downstairs I will install a 22mm downfall plus a 22mm end
to
carry the pipe further right for about 4 or 5 metres before it meets
the
pump.

Is this a bad idea? Will the pump hate to be miles away from the tank?
Will the use of fat pipes override this need? Will I still need some
sort
of flange even though the supply to the hot tank and the output are
both
28mm fat? Ought I to make the final 4 or 5 metre run in 28mm after all?

Any experiences gratefully accepted; thanks in advance.

Mungo

Out the top of my hot cylinder I plumbed the outlet in 28mm copper,
which gracefully (45 degree elbow) slopes down to floor level where the
28mm pipework ends in an compression T piece with 22mm pipework either
side.

I wouldn't use 28mm from the cylinder outlet, particularly when pumped. All
it does it mean it takes longer for actual hot water to come out at the end.
I'd have the pump next to the cylinder and run either 15mm (for a shower
room) or 22mm (for a bathroom) from there. I would even consider using 15mm
to a bathroom. It is the connection between the cold tank and the bottom of
the hot water cylinder that would be seriously helped by a short as possible
28mm connection.

Basically, from the top of the cylinder, you should have 22mm going up to
the vent over the tank. Then 22mm should be teed off straight into the pump.
The outlet from the pump can be 22mm or 15mm to the rest of the house. Any
desired gravity outlet (i.e. kitchen sink) can come off before the pump. I'd
use a single impellor pump for this, and mains cold, if the mains is good
enough.

Christian.

Then 22mm should be teed off straight into the pump.

You should note by "should", I mean if it is not possible to install a
flange, which would be superior.

Christian.

"Big Al" wrote in message
oups.com...
Ok. I know there are countless discussion topics on this (I've read
them!) but I'm after a little confirmation before I go cutting into my
pipework.

I am fitting a new shower to the bathroom with a separate pump. After
much deliberation, I have run a dedicated 22mm cold feed from my CW
cistern in the loft into my airing cupboard on the 1st floor. The twin
input pump is to be placed on the floor in the cupboard alongside the
HW tank. I now need to supply hot water from the HW tank.

Wishing to avoid a Essex / Wessex / Surrey or any fiddling with flanges
on the HW tank, I could T into the 22mm vertical pipe that is the vent
and HW supply for the bath. This `should` be ok. However, it would be
infinitely easier for me to T into the horizontal coming from the HW
tank that connects to the vent pipe / bath supply. If I brought a
downwards pipe from this horizontal to the pump would all be ok or am I
asking for trouble?

Kind regards

Alun


I take it the hot water tank has been plumbed with a combined expansion and
draw off pipework scheme, by the way you describe it. If you can take
outlets from the hot outlet as low down to the floor as you can, then you
won't have any problems of dragging air into your pump from the expansion
pipe.

Looking at the pipework you have, you should be seeing a 22 mm Equal TEE
with the branch pointing toward the top of the hot water cylinder, right?

The straight through part of the TEE is pointing vertically straight up and
down, correct?

The pipework coming from the lower connection, toward the floor, is the
supply to the water system for the rest of the house, is this right?

So, what you need is a plan to supply the pump with constant hot water, but
you also need to keep the rest of the house supplied from the same point,
right?

If all the above have been answered with a "Yes", then you really only need
to place another 22 mm TEE fitting to the section of pipe that drops toward
the floor. You will be better off keeping it as low to the floor as you
possibly can, but the pump is only supplying one shower that is presumably
very close to where the pump is sited. Let's say, within a couple of
metres?

You're running the feed pipes for the shower head in 15 mm, for both, aren't
you?

If this is also a "Yes" answer, then the 22 mm pipework for the twin pump
will be well able to supply the shower without problems.

I don't understand why you had to run a separate 22 mm feed from the cold
tank, when you could have drawn you cold supply for the pump off the same
supply that feeds the hot water tank. Both pipes would have been in the
place, and would have been less hassle, in my way of thinking, than doing
all that un-necessary work.

Pipes of 22 mm diameter will quite happily supply three 15 mm diameter pipes
without any major losses. You would have two 22 mm pipes to the pump, and
each of these pipes are only supplying one 15 mm pipe each on the outlet of
the pump. The difference in the flow rate of the water between the supply
and outlet sides of the pump would be minimal. All you need the pump to do
is keep a constant head of water to keep the shower head flowing nicely.

On 12 May 2005 01:02:08 -0700, "Big Al"
wrote:

Ok. I know there are countless discussion topics on this (I've read
them!) but I'm after a little confirmation before I go cutting into my
pipework.

I am fitting a new shower to the bathroom with a separate pump. After
much deliberation, I have run a dedicated 22mm cold feed from my CW
cistern in the loft into my airing cupboard on the 1st floor. The twin
input pump is to be placed on the floor in the cupboard alongside the
HW tank. I now need to supply hot water from the HW tank.

Wishing to avoid a Essex / Wessex / Surrey or any fiddling with flanges
on the HW tank, I could T into the 22mm vertical pipe that is the vent
and HW supply for the bath. This `should` be ok. However, it would be
infinitely easier for me to T into the horizontal coming from the HW
tank that connects to the vent pipe / bath supply. If I brought a
downwards pipe from this horizontal to the pump would all be ok or am I
asking for trouble?

Kind regards

Alun

I would seriously suggest that you do need to Essex flange
it,preferably a flange with no internal shoulder stop so that the pipe
can be fed into the centre of the cylinder.

joe

Hi BigWallop

Many thanks for this - you've described my pipework pretty accurately.

I've put the dedicated 22mm cold feed for the pump to be sure that no
other cold water draw will impact the shower. The other options were
to take a feed from the 22mm cold for the bath or, as you suggest, the
28mm feed for the HW tank. Neither of these seem suitable to me as if
I take from the bath feed I run the risk of impacting / being impacted
by someone running a bath at the same time (it happens!) and if I take
from the cold feed to the HW tank I am directly impacting the hot water
flow (I think..).

The main reason for my question is that whilst I appreciate that a
flange of some description will minimize the likelihood of the pump
drawing air, I don't wish to fit one if I can avoid it. Tapping into
the HW pipe as low down as possible makes a lot of sense but a further
complication is that my existing pipes are butted up against a wall.
Cutting into them will be a pain in the a*$e. If there are no obvious
clangers with cutting into the HW pipe just before the TEE of the
expansion / draw off pipe then my life is much easier I think.

Hi Christian,
Ta for the info.
Apologies to "Big Al" for hijacking his thread.

Mungo

I don't understand why you had to run a separate 22 mm feed from the cold
tank, when you could have drawn you cold supply for the pump off the same
supply that feeds the hot water tank.

The problem there is that this will reduce the flow into the bottom of the
cylinder, making it very likely that the hot side of the pump will suck air.

Christian.

"Big Al" wrote in message
ups.com...
Hi!
"
Many thanks for the reply. I think I am ok with the feed from the CW
cistern to the HW tank as it is already 28mm. The pipe I have added is
a dedicated 22mm from CW cistern to the pump.

Adding a length of 28mm to the vent pipe should be ok. I guess this
means that there is more water held above the pump and hence the pump
is less likely to suck it all through?
"

Yep.

"
Re - `Tee as close as possible to the HW cylinder`. Does that mean
that there should be no difference teeing into the horizontal section
than there is teeing into the vertical bath / vent pipe?
"

The closer the pump tee is to the cylinders hot water draw-off, the better.

"Ian_m" wrote in message
...
"Big Al" wrote in message
ups.com...
"
Hi!

Many thanks for the reply. I think I am ok with the feed from the CW
cistern to the HW tank as it is already 28mm. The pipe I have added is
a dedicated 22mm from CW cistern to the pump.

Adding a length of 28mm to the vent pipe should be ok. I guess this
means that there is more water held above the pump and hence the pump
is less likely to suck it all through?

Re - `Tee as close as possible to the HW cylinder`. Does that mean
that there should be no difference teeing into the horizontal section
than there is teeing into the vertical bath / vent pipe?

Doesn't matter what size pipe you are using, the pump will suck the water
out the vent pipe and pull air through, using a wider pipe will just delay
the air inrush by a couple of milliseconds.... been there done that.....

Ended up doing "a propper job" with a Warix flange on top of tank after
a*sing around bodging the vent. Did you ever wonder why all the shower
pump
fitting instructions say you must use a flange ? well they are right use
flange.

If I was fitting again I would use an Essex flange, fitted/cut into the
side
of the tank
"

If you were doing it again it is best to use one of these, and no pump. A
shower coil cylinder with a quick recovery coil, killing many birds with one
stone:

- mains pressure shower
- quick recovery means cheaper gas bills
- quick recovery means the cylinder is effectively larger as it will produce
more hot water.
- quiet (no noisy pumps).
- shower coil is simple
- shower coil is reliable,
- greater control at the mixer
- cheap to run with water heated by gas.
- a cheaper shower mixer valve can be used too.
- the existing system has no disruption except a cylinder change.
- no electrical work.

The only tap you need high pressure at is the shower. The cold water feeding
the cold tank in the loft usually runs up inside the airing cupboard meaning
all the pipework is in the cupboard. I would avoid pumps.

http://www.rcmgroup.co.uk/mains_pres...ower/index.htm

The indirect version. Use a normal high pressure thermostatic shower mixer.
If the shower does not perform as well as you thought. Ramp up the cylinder
temperature and install a DHW blending valve on the draw-off. Comes with a
pressure reducing valve. Take the cold off this valve too. Will give a
high pressure shower without any pumps and minimal disruption.

"BigWallop" wrote in message
. uk...

"Big Al" wrote in message
oups.com...

"
Ok. I know there are countless discussion topics on this (I've read
them!) but I'm after a little confirmation before I go cutting into my
pipework.

I am fitting a new shower to the bathroom with a separate pump. After
much deliberation, I have run a dedicated 22mm cold feed from my CW
cistern in the loft into my airing cupboard on the 1st floor. The twin
input pump is to be placed on the floor in the cupboard alongside the
HW tank. I now need to supply hot water from the HW tank.

Wishing to avoid a Essex / Wessex / Surrey or any fiddling with flanges
on the HW tank, I could T into the 22mm vertical pipe that is the vent
and HW supply for the bath. This `should` be ok. However, it would be
infinitely easier for me to T into the horizontal coming from the HW
tank that connects to the vent pipe / bath supply. If I brought a
downwards pipe from this horizontal to the pump would all be ok or am I
asking for trouble?

Kind regards

Alun

I take it the hot water tank has been plumbed with a combined expansion
and
draw off pipework scheme, by the way you describe it. If you can take
outlets from the hot outlet as low down to the floor as you can, then you
won't have any problems of dragging air into your pump from the expansion
pipe.

Looking at the pipework you have, you should be seeing a 22 mm Equal TEE
with the branch pointing toward the top of the hot water cylinder, right?

The straight through part of the TEE is pointing vertically straight up
and
down, correct?

The pipework coming from the lower connection, toward the floor, is the
supply to the water system for the rest of the house, is this right?

So, what you need is a plan to supply the pump with constant hot water,
but
you also need to keep the rest of the house supplied from the same point,
right?

If all the above have been answered with a "Yes", then you really only
need
to place another 22 mm TEE fitting to the section of pipe that drops
toward
the floor. You will be better off keeping it as low to the floor as you
possibly can, but the pump is only supplying one shower that is presumably
very close to where the pump is sited. Let's say, within a couple of
metres?

You're running the feed pipes for the shower head in 15 mm, for both,
aren't
you?

If this is also a "Yes" answer, then the 22 mm pipework for the twin pump
will be well able to supply the shower without problems.

I don't understand why you had to run a separate 22 mm feed from the cold
tank, when you could have drawn you cold supply for the pump off the same
supply that feeds the hot water tank.
"

Cold supplies to shower "must" have a dedicated supply. This ensures no
scalding. Not to do so is irresponsible.

"

SNIP



Just follow the instructions with the shower pump, for example
http://www.techflow.co.uk/qtinstall.htm. They are not done like this just to
make it hard for you, they are done like this because it works.

I tried 22mm T in vent pipe as it was easy, especially using plastic push
fit, cut pipe insert T connect to pump, job done except I ended up with a
cavitating pump and basically an air/water shower. Fitted a flange and had a
water shower.

Placing 28mm section in vent pipe will make no difference, the pump will
pull the water from the easiest source which is the vent, you need a proper
flange that does not allow the air in.

As for the person who said if you are running runs up into the loft and over
to shower needing a vent valve to let trapper air out WHY ??? As soon as you
turn the shower on the air gets pushed out immediatly.