Is there an easy way of telling the difference between a DHW fast
recovery cylinder and a ... don't know the terminology. Slow recovery
cylinder?

My cylinder is pre-insulated and has 22mm coil connections near the
bottom and about half way up.

Thanks

Pete

On Wed, 11 Oct 2006 18:17:50 +0100, pm
wrote:

Is there an easy way of telling the difference between a DHW fast
recovery cylinder and a ... don't know the terminology. Slow recovery
cylinder?

My cylinder is pre-insulated and has 22mm coil connections near the
bottom and about half way up.

Thanks

Pete

The answer to your question is:

When you run the water out, does it reheat quickly?
If yes, you probably have a fast recovery one.

On Wed, 11 Oct 2006 18:17:50 +0100 Pm wrote :
Is there an easy way of telling the difference between a DHW fast
recovery cylinder and a ... don't know the terminology. Slow recovery
cylinder?

Not that I know of, unless there's a label with useful information

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk

EricP wrote:
On Wed, 11 Oct 2006 18:17:50 +0100, pm
wrote:


Is there an easy way of telling the difference between a DHW fast
recovery cylinder and a ... don't know the terminology. Slow recovery
cylinder?

My cylinder is pre-insulated and has 22mm coil connections near the
bottom and about half way up.

Thanks

Pete


The answer to your question is:

When you run the water out, does it reheat quickly?
If yes, you probably have a fast recovery one.


Don't know. In the summer I use an immersion heater. In the winter the
CH and DHW is on constantly so it doesn't really run out. I am
converting my CH system to S-plan and putting a tank stat on the tank,
the instructions state different mounting locations for fast recovery
and non fast recovery.

pm wrote in
:

Is there an easy way of telling the difference between a DHW fast
recovery cylinder and a ... don't know the terminology. Slow recovery
cylinder?

My fast recovery cylinder uses a pipe, or immersion thermostat.

This plugs in right at the bottom, not straps on at the side.

I've no idea if all fast recovery cylinders are like this, or any
conventional ones.

But it may give you a clue

mike

On Wed, 11 Oct 2006 18:17:50 +0100, pm
wrote:

Is there an easy way of telling the difference between a DHW fast
recovery cylinder and a ... don't know the terminology. Slow recovery
cylinder?

My cylinder is pre-insulated and has 22mm coil connections near the
bottom and about half way up.

Thanks

Pete
unlikely, how old is you system?

marvelus wrote:
On Wed, 11 Oct 2006 18:17:50 +0100, pm
wrote:


Is there an easy way of telling the difference between a DHW fast
recovery cylinder and a ... don't know the terminology. Slow recovery
cylinder?

My cylinder is pre-insulated and has 22mm coil connections near the
bottom and about half way up.

Thanks

Pete

unlikely, how old is you system?

The cylinder is about 4 years old. The boiler was over 20 years old.

On 2006-10-11 18:17:50 +0100, pm said:

Is there an easy way of telling the difference between a DHW fast
recovery cylinder and a ... don't know the terminology. Slow recovery
cylinder?

My cylinder is pre-insulated and has 22mm coil connections near the
bottom and about half way up.

Thanks

Pete

There are a couple of ways:

- Drain the cylinder, take out the immersion and look inside with a torch.

- A science experiment.

+ Block the bottom connection of the coil with a bung.
+ Attach a length of transparent plastic tube plus a funnel to the top
coil connection.
+ Place a measuring jug under the lower connection.
+ Fill the coil slowly with water using the funnel until you see the
transparent tube just beginning to fill.
+ Pull out the bung and measure the volume of water.
+ Unless you have one of the cylinders with a group of small tubes as a
coil (one manufacturer does these - can't remember which), the coil
typically consists of 22mm tube.
+ From the volume of water, and the tube diameter (radius to calculate
cross sectional area - pi x radius squared) you can determine the
length of tube.
+ The diameter of the coil is typically half to two thirds of the
cylinder diameter.
+ Therefore, from the length of tube you can calculate both the number
of turns and surface area of tube.

A fast recovery cylinder has a large surface are of tube and many coil
turns - perhaps 10+. A conventional one generally has three or four.

While this is far from precise science, it should be close enough to
work out what you have.

Andy Hall wrote:
On 2006-10-11 18:17:50 +0100, pm said:

Is there an easy way of telling the difference between a DHW fast
recovery cylinder and a ... don't know the terminology. Slow recovery
cylinder?

My cylinder is pre-insulated and has 22mm coil connections near the
bottom and about half way up.

Thanks

Pete


There are a couple of ways:

- Drain the cylinder, take out the immersion and look inside with a torch.

- A science experiment.

+ Block the bottom connection of the coil with a bung.
+ Attach a length of transparent plastic tube plus a funnel to the top
coil connection.
+ Place a measuring jug under the lower connection.
+ Fill the coil slowly with water using the funnel until you see the
transparent tube just beginning to fill.
+ Pull out the bung and measure the volume of water.
+ Unless you have one of the cylinders with a group of small tubes as a
coil (one manufacturer does these - can't remember which), the coil
typically consists of 22mm tube.
+ From the volume of water, and the tube diameter (radius to calculate
cross sectional area - pi x radius squared) you can determine the length
of tube.
+ The diameter of the coil is typically half to two thirds of the
cylinder diameter.
+ Therefore, from the length of tube you can calculate both the number
of turns and surface area of tube.

A fast recovery cylinder has a large surface are of tube and many coil
turns - perhaps 10+. A conventional one generally has three or four.

While this is far from precise science, it should be close enough to
work out what you have.




I would rather not disturb the connections now so can I ask a slightly
different question - does it make a huge difference where the tank stat
goes? The instructions say half way up, unless it is a fast-recovery
type in which case at the top.

I would rather not disturb the connections now so can I ask a slightly
different question - does it make a huge difference where the tank stat
goes? The instructions say half way up, unless it is a fast-recovery type
in which case at the top.

The tank stat should go nearish the bottom, but a couple of coils worth
above the bottom coil connection. If you put it near the top, you'll only
use a fraction of the capacity.

Christian.

On Oct 12, 9:31 am, pm wrote:
I would rather not disturb the connections now so can I ask a slightly
different question - does it make a huge difference where the tank stat
goes? The instructions say half way up, unless it is a fast-recovery
type in which case at the top

Doesn't sound right to me. You want the water to be heated down to the
bottom (or near) of the cylinder before the stat turns off the heat.

MBQ

Christian McArdle wrote:
I would rather not disturb the connections now so can I ask a slightly
different question - does it make a huge difference where the tank stat
goes? The instructions say half way up, unless it is a fast-recovery type
in which case at the top.


The tank stat should go nearish the bottom, but a couple of coils worth
above the bottom coil connection. If you put it near the top, you'll only
use a fraction of the capacity.

Christian.




I've just looked at the online literature
http://www.danfoss-randall.co.uk/sit...oads/34234.PDF, the bit about
mounting near the top is not in there, the date on the online guide is
08/00 whereas the booklet that came with the unit is 06/06.

The details in my booklet are more like
http://www.danfoss-randall.co.uk/sit...loads/4457.PDF page 2
"Electric Immersion and fast recovery systems".

Also would it make a difference whether the flow is top to bottom or
bottom to top?

On 12 Oct 2006 04:02:37 -0700, "
wrote:



On Oct 12, 9:31 am, pm wrote:
I would rather not disturb the connections now so can I ask a slightly
different question - does it make a huge difference where the tank stat
goes? The instructions say half way up, unless it is a fast-recovery
type in which case at the top

Doesn't sound right to me. You want the water to be heated down to the
bottom (or near) of the cylinder before the stat turns off the heat.

MBQ

But the water is heated from the bottom.

On Oct 13, 8:08 am, marvelus wrote:
On 12 Oct 2006 04:02:37 -0700, "

wrote:

On Oct 12, 9:31 am, pm wrote:
I would rather not disturb the connections now so can I ask a slightly
different question - does it make a huge difference where the tank stat
goes? The instructions say half way up, unless it is a fast-recovery
type in which case at the top

Doesn't sound right to me. You want the water to be heated down to the
bottom (or near) of the cylinder before the stat turns off the heat.

MBQ

But the water is heated from the bottom.


OK, there will be convection but that aside think of the following...

The hot water is drawn off from the top with cold entering at the
bottom. If the stat is at the top then the heating will not kick in
again until you've emptied the cyclinder and the stat sense the cold
water reaching the top. With the stat in the usual place the heating
will kick in before you exhaust the supply of hot water.

MBQ