Hello all,

Just though I'd call in here to run this one past the more experienced...

I currently have a gravity fed hot water system. I'm about to build a small
extension and will replace the current boiler while doing so. I have
pondered for a while the idea of a mains pressure hot water system but am
really concerned about the lack of pressure at the upstairs shower. I
currently have a pressure pump installed and the shower is brilliant. I also
like the idea of a combi simply because of the fact that I'll never "run
out" of hot water.

Anyway, after reading loads of stuff on the web I have concluded (maybe
wrongly!!) that I should have a combi to feed everything but the showers and
retain the current hot water cylinder and pump just for the showers. I'd
obviously have to somehow plumb in the system to heat the water cylinder and
that will no doubt necessitate the use of motorised valves etc. I realise
that I'll still need to keep the loft tanks but don't mind that. I'll also
have two hot water supplies in case one fails and stored water in the loft
is always handy should there be a mains supply problem.

So, am I thinking right? and is there any where on the web where I can
source a plumbing & wiring diagram for this type of set up? I can plumb and
wire but haven't a clue where to start on this. I'll obviously need the
boiler to be on call for the central heating and the hot water and these
need to be independent.

Any other idea's appreciated too.

I have pondered for a while the idea of a mains pressure hot water system
but am really concerned about the lack of pressure at the upstairs shower.

Assuming that the mains pressure and flow is good, I'd do it the other way
round. Have the shower (and possibly kitchen tap) off the combi, and run the
bath from the cylinder, possibly using the pump.

Of course, you shouldn't rule out a mains pressure storage system which
gives the best of both worlds. I've just collected such a system this
morning, a 180l DPS Pandora. I'll let everyone know if it works once it is
finally connected up.

I'll obviously need the boiler to be on call for the central heating
and the hot water and these need to be independent.

You wire and plumb it just like you would a conventional heating system. You
will have to discard any boiler built in programmer, as it will only have
one channel. Either lose it, or set it to 24/7.

Decide on either Honeywell 'Y' or 'S' plan. Wire up in the conventional
fashion and lash up the final call for heat to the room thermostat
connection on the boiler. You'll probably need a volt free contact at the
end, so choose a programmer that has volt free contacts, as otherwise,
you'll need a relay, unless the boiler can accept a 230V call for heat.

Christian.

Christian McArdle wrote:

I have pondered for a while the idea of a mains pressure hot water system
but am really concerned about the lack of pressure at the upstairs shower.


Assuming that the mains pressure and flow is good, I'd do it the other way
round. Have the shower (and possibly kitchen tap) off the combi, and run the
bath from the cylinder, possibly using the pump.

Of course, you shouldn't rule out a mains pressure storage system which
gives the best of both worlds. I've just collected such a system this
morning, a 180l DPS Pandora. I'll let everyone know if it works once it is
finally connected up.


I've got one. Shoehorned the HW tank into the loft. Saves a lot of
space. Plumbing is more intricate - lots of safety pipes to dump
pressure outside etc, but overall performance is better than anything
else. Combis have pressure, but no flow rate IMHO, unless you go for a
really BIG one. Combis need to have heating capacity for peak hot water
flow. Mains pressure tank? You have three or four baths worth on tap all
teh time. Boiler needn't be as big.

I'd only use a combi on a strict budget, or in a small house with no
room for a HW tank.

I'd never use a gravity fed header tank unless teh local water supply
was known to be highly unreliable.

Here, water is 100% reliable, but electricity is not. No sparks means no
boiler. But HW tank is good for several baths, aga needs no psarks to
cook, and open fires take cxare of heating, and candles just about sort
out lighting. And battery radio allows local news coverage of 'national
electrical crisis'

AND I can recharge its batteris from the car.

I've just collected such a system this morning, a 180l DPS Pandora.

I've got one. Shoehorned the HW tank into the loft. Saves a lot of
space. Plumbing is more intricate - lots of safety pipes to dump
pressure outside etc,

The DPS Pandora is different from your system, though. Lower maximum flow
rates and won't work at all without electricity. However, it doesn't require
lots of safety pipes to dump pressure, which is the main reason I bought it.

Christian.

"Christian McArdle" wrote in message
et...
I've just collected such a system this morning, a 180l DPS Pandora.

I've got one. Shoehorned the HW tank into the loft. Saves a lot of
space. Plumbing is more intricate - lots of safety pipes to dump
pressure outside etc,

The DPS Pandora is different from your system,
though. Lower maximum flow rates

That can be sorted by installing another plate heat exchangers in parallel.
That's if you need very high flow rates of course.

and won't work at all without electricity. However, it doesn't require
lots of safety pipes to dump pressure,

Or an overflow pipe either, so can be fitted in the centre of a house, like
under the stairs , right out of the way. Large metals pipes penetrating
walls can be a large heat sink.

which is the main reason I bought it.




---
--

Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.520 / Virus Database: 318 - Release Date: 18/09/2003

At the risk of starting WW3.5, is it possible to add a mains storage system
to an existing (Bosch Worcester Greenstar) combi?

And if so any recomendations?

TIA

Bax


"Christian McArdle" wrote in message
et...
I have pondered for a while the idea of a mains pressure hot water system
but am really concerned about the lack of pressure at the upstairs
shower.

Assuming that the mains pressure and flow is good, I'd do it the other way
round. Have the shower (and possibly kitchen tap) off the combi, and run
the
bath from the cylinder, possibly using the pump.

Of course, you shouldn't rule out a mains pressure storage system which
gives the best of both worlds. I've just collected such a system this
morning, a 180l DPS Pandora. I'll let everyone know if it works once it is
finally connected up.

I'll obviously need the boiler to be on call for the central heating
and the hot water and these need to be independent.

You wire and plumb it just like you would a conventional heating system.
You
will have to discard any boiler built in programmer, as it will only have
one channel. Either lose it, or set it to 24/7.

Decide on either Honeywell 'Y' or 'S' plan. Wire up in the conventional
fashion and lash up the final call for heat to the room thermostat
connection on the boiler. You'll probably need a volt free contact at the
end, so choose a programmer that has volt free contacts, as otherwise,
you'll need a relay, unless the boiler can accept a 230V call for heat.

Christian.

"Baxter Basics" wrote in message
et...

At the risk of starting WW3.5, is it possible to add a mains storage
system
to an existing (Bosch Worcester Greenstar) combi?

Yes.

And if so any recomendations?

The Pandora, as below.

"Christian McArdle" wrote in message
et...
I have pondered for a while the idea of a mains pressure hot water
system
but am really concerned about the lack of pressure at the upstairs
shower.

Assuming that the mains pressure and flow is good, I'd do it the other
way
round. Have the shower (and possibly kitchen tap) off the combi, and run
the
bath from the cylinder, possibly using the pump.

Of course, you shouldn't rule out a mains pressure storage system which
gives the best of both worlds. I've just collected such a system this
morning, a 180l DPS Pandora. I'll let everyone know if it works once it
is
finally connected up.

I'll obviously need the boiler to be on call for the central heating
and the hot water and these need to be independent.

You wire and plumb it just like you would a conventional heating system.
You
will have to discard any boiler built in programmer, as it will only
have
one channel. Either lose it, or set it to 24/7.

Decide on either Honeywell 'Y' or 'S' plan. Wire up in the conventional
fashion and lash up the final call for heat to the room thermostat
connection on the boiler. You'll probably need a volt free contact at
the
end, so choose a programmer that has volt free contacts, as otherwise,
you'll need a relay, unless the boiler can accept a 230V call for heat.

Christian.






---
--

Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.520 / Virus Database: 318 - Release Date: 18/09/2003

At the risk of starting WW3.5, is it possible to add a mains storage
system
to an existing (Bosch Worcester Greenstar) combi?

Yes. You can add anything to a combi that could be added to a conventional
boiler. A combi is just a conventional boiler with an additional
instantaneous hot water heat exchanger and associated controls.

You'll need a pile of extra controls, programmers and valves, as would be
required for a heating system using a conventional boiler. These are
frequently packaged into convenient kits with substantial discounts.

And if so any recomendations?

There are two main contenders. Both are similar in purchase cost. Both
vastly superior to a combi boiler in performance, assuming your mains can
supply the water.

a) An unvented hot water cylinder. This provides the ultimate flow rate,
assuming your mains can supply it. It requires extra safety controls, which
mean that you need a specific safety inspection for building regulations or
a specifically qualified installer. Example: Heatrae Sadia Megaflo.

b) A heat bank (or thermal store, which is similar). This provides good flow
rates (again assuming good mains supply), but not as good as the unvented
cylinder. It is inherently safer as the hot water storage itself is at
atmospheric pressure, so is not subject to potentially dangerous pressure
rises when heated. This makes is much easier to install. Example: DPS
Pandora (also available with complete CH+DHW 'Y' or 'S' plan system controls
and 2 channel programmer ready mounted to the cylinder).

I've just bought a DPS Pandora, but it won't be connected for a week or two.
It looks the part, though. We've managed to hoist it into the loft, where
there is no convenient overflow or pressure relief outlet due to a planned
dormer extension.

Christian.

Assuming that the mains pressure and flow is good, I'd do it the other way
round. Have the shower (and possibly kitchen tap) off the combi, and run
the
bath from the cylinder, possibly using the pump.

Eh?!

Assuming that the mains pressure and flow is good, I'd do it the other
way
round. Have the shower (and possibly kitchen tap) off the combi, and run
the
bath from the cylinder, possibly using the pump.

Eh?!

Showers need pressure as much as they need flow. This means that an
excellent shower can be obtained by a combi, which uses mains pressure but
is limited in flow rate. It will also be less noisy, as no pump is needed.

The cylinder is capable of supplying much higher flow rates. However,
gravity feed might not be able to get sufficient flow rate at the taps, for
which a pump can be beneficial.

Christian.

"Christian McArdle" wrote in message
et...
Assuming that the mains pressure and flow is good, I'd do it the other
way
round. Have the shower (and possibly kitchen tap) off the combi, and
run
the
bath from the cylinder, possibly using the pump.

Eh?!

Showers need pressure as much as they need flow. This means that an
excellent shower can be obtained by a combi, which uses mains pressure but
is limited in flow rate. It will also be less noisy, as no pump is needed.

The cylinder is capable of supplying much higher flow rates. However,
gravity feed might not be able to get sufficient flow rate at the taps,
for
which a pump can be beneficial.

You obviously mean just for a shower as a tank fed bath can supply very high
flow rates, but poor pressure.


---
--

Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.520 / Virus Database: 318 - Release Date: 18/09/2003

You obviously mean just for a shower as a tank fed bath can supply very
high
flow rates, but poor pressure.

That would depend on the pipe diameter and routing. Most gravity fed baths
I've used have had substandard flow rates, sometimes not much more than a
combi boiler. A pump is often quite an improvement. The problems occur when
the hot water cylinder is tucked away somewhere quite different from the
location of the bath and the cold water tank, leading to convoluted pipe
runs, sometimes even run in 15mm pipe. It is these situations that a pump is
often quite an improvement as far as baths are concerned. With showers, you
usually need a pump to improve the pressure so that the water can squeeze
through the holes.

Christian.

Christian, do the manufacturers of the Pandora have a web presence?

TIA

Bax


"Christian McArdle" wrote in message
et...
I have pondered for a while the idea of a mains pressure hot water system
but am really concerned about the lack of pressure at the upstairs
shower.

Assuming that the mains pressure and flow is good, I'd do it the other way
round. Have the shower (and possibly kitchen tap) off the combi, and run
the
bath from the cylinder, possibly using the pump.

Of course, you shouldn't rule out a mains pressure storage system which
gives the best of both worlds. I've just collected such a system this
morning, a 180l DPS Pandora. I'll let everyone know if it works once it is
finally connected up.

I'll obviously need the boiler to be on call for the central heating
and the hot water and these need to be independent.

You wire and plumb it just like you would a conventional heating system.
You
will have to discard any boiler built in programmer, as it will only have
one channel. Either lose it, or set it to 24/7.

Decide on either Honeywell 'Y' or 'S' plan. Wire up in the conventional
fashion and lash up the final call for heat to the room thermostat
connection on the boiler. You'll probably need a volt free contact at the
end, so choose a programmer that has volt free contacts, as otherwise,
you'll need a relay, unless the boiler can accept a 230V call for heat.

Christian.

Christian, do the manufacturers of the Pandora have a web presence?

www.heatweb.com

The website isn't quite up to date. AFAICT, the "2002" specification
heatbanks have been replaced with "5670" specification types referred to as
Pandoras (which are mentioned). However, the general principles and
specifications are similar and (I'm told) prices reduced. The prices aren't
listed on the website, but are very similar to equivalent Megaflos as listed
by discountedheating.com if you want some idea.

The company is of the a small friendly variety. This means that lead times
aren't that great (it isn't off the shelf at a plumber's merchant like a
Megaflo), but they are able to build the things to a precise specification,
if a standard model isn't quite right.

Christian.

"Christian McArdle" wrote in message
et...
Christian, do the manufacturers of the Pandora have a web presence?

www.heatweb.com

What is your spec? Does it have a blending valve on the flow and return?


---
--

Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.520 / Virus Database: 318 - Release Date: 18/09/2003

What is your spec? Does it have a blending valve on the flow and return?

No blending valve. The indirect coil comes unadorned. There is a
thermostatic mixing valve on the DHW outlet, though.

I'm certainly interested in anything that can reduce the return temperature,
though. I wouldn't mind reducing the radiator flow temperature, too, for
safety reasons. I have a five year old, whose bed is adjacent to a radiator.
Can blending valves achieve this?

Christian.

"Christian McArdle" wrote in message
et...
Christian, do the manufacturers of the Pandora have a web presence?

www.heatweb.com

The website isn't quite up to date. AFAICT, the "2002" specification
heatbanks have been replaced with "5670" specification types referred to
as
Pandoras (which are mentioned). However, the general principles and
specifications are similar

Christian,

Who sized your 180 litre heat bank?


---
--

Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.520 / Virus Database: 318 - Release Date: 18/09/2003

Who sized your 180 litre heat bank?

Me, supported by the simple table on their website and a quick chat with
their sales director. It is based on having a bath and a shower
simultaneously.

Christian.