Dear Group,

Following advice from the archives of this group we've had a thermal
store installed to service our house with it's gleaming new extension.
The store is a 350 litre Gledhill Torrent RE Solar in the loft, and a
Ferolli 25OV boiler installed in the loft too.
There is a "hot water" / "heating" programmable timer that operate the
two zone valves, (as per the Gledhill wiring diagram), and a Heatmiser
programmable room stat in the lounge.
There are 50 evacuated solar tubes installed on the roof for the solar
side of things, along with their associated pump, controller etc.

The system is built pretty much as per page 4 of the Gledhill manual;
http://www.gledhill.net/pdfmanuals/B...entRE-Iss3.pdf
(but with no underfloor heating circuit).

What I'm looking for is advice from those who've been there on how to
set up timers, bypass valves etc, so as to best utilise the system.

I think I'm fairly clear on what needs to happen in the summer; My
idea is to set the "hot water" to come on before sunrise for half an
hour or so, to ensure that the store is adequately charged for morning
ablutions, and then hope that the sun fully charges the store
throughout the day.

The quandry is what to do in the current, wintery climate? The system
is currently wired as per page 9 of the above manual, with the store
thermostat set to 75C, and it seems to me that the problem with this
setup is that the boiler only fires, (and hence the store only heats),
when the room stat calls for heat. This means that once the room
temperature has been satisfied then the store may be left only
partially charged, thus potentially compromising the ability to
provide hot-enough DHW. (and IIUC also doesn't help prevent the boiler
cycling that thermal stores are supposed to help with).
Is the answer to have the store permanently charged, and just use the
room stat to operate the heating zone valve?
i.e either set the "hot water" timer to be on whenever the heating
timer is on, or alternatively wire the "heating timer" to operate the
pump/cylinder stat, and have the programmable room stat merely switch
the heating zone valve?
Obviously I also still want to extract as much of the suns meagre
solar offerings as possible, and so the ideal for this is to have as
cool a store as possible... hmmm.

Previous posters have written of the advantages of being able to
rapidly dump heat from the store into the radiators, and hence quickly
heat the home. This is one area that is currently slightly
disappointing.
If you look at the photograph on page 7 of the manual you can see that
the cylinder thermostat is roughly in line with the entering (boiler
flow), hot water. However, the water that is pumped *from* the store
around the heating system comes from, I would guess, 40-50cm below
this stat, and is therefore considerably cooler. Is this right /
normal, and how does it fit in with the rapid-heat-up scenario?

Finally, can anyone offer any advice as to how to set up the automatic
bypass valve. What kind of figure does it need to be set to, (IIRC
the range is 0.05 to 0.5 bar). Are there any tips or 'usual' settings
for this?

Any advice from the several subscribers who have similar systems on
how best to optimise my system is very much appreciated.

Many thanks, Mike H

On Sat, 6 Dec 2008 13:34:31 -0800 (PST) someone who may be pepper
wrote this:-

The system is built pretty much as per page 4 of the Gledhill manual;

A lot of questions. When I have had time to digest it I will try and
reply.



--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

"pepper" wrote in message
...
Dear Group,

One thing I must ask, is why you say the room 'stat must satisfy the heating
but might leave the heat store partially charged? The central heating
should not interfere with the DHW side of things at all. You should set the
DHW to the temperature you want it, then leave it alone. It should not be
connected to a room 'stat or any other thermostat other than the ones which
control the heat store itself.

The programmable 'stat in your room is for the central heating, and nothing
else other than the central heating.

So why should the room 'stat have any effect on your heat store and DHW
system? Although you have correctly identified the mistake at the end of
the paragraph on this matter.

The heat store should actually heat quite evenly across its full length and
breadth, so the thermostat on the store is placed in a more central position
than on a normal small hot water cylinder. Because the store should be
pretty constantly charged all the time, it can then be used to dump heat
back into the central heating side to give a rapid sort of boost before the
actual heating has got up to temperature. That's why the store should be
set and forgotten. It's why this type of storage and heating system is
used, all be it on a larger scale, in most commercial developments now.

Setting the automatic by-pass valve. It is easier to set the by-pass valve
if you can disconnect the zone valves from the power, but leave the rest of
the system running as normal.

First, open the zone valves manual and set the system running. The by-pass
valve should be closed to allow normal operation. Now close both zone
valves and the by-pass valve should open to allow circulation through it.
If it doesn't, then adjust it. If it opens while in normal operation, it is
to sensitive and also needs adjusted. That's the easy way to set the
by-pass valve.

Have a play around with it all, it can't bite. And have fun with it.

"BigWallop" wrote in message
. ..

"pepper" wrote in message
...
Dear Group,

One thing I must ask, is why you say the room 'stat must satisfy the
heating
but might leave the heat store partially charged? The central heating
should not interfere with the DHW side of things at all. You should set
the
DHW to the temperature you want it, then leave it alone. It should not be
connected to a room 'stat or any other thermostat other than the ones
which
control the heat store itself.

The programmable 'stat in your room is for the central heating, and
nothing
else other than the central heating.

So why should the room 'stat have any effect on your heat store and DHW
system? Although you have correctly identified the mistake at the end of
the paragraph on this matter.

The heat store should actually heat quite evenly across its full length
and
breadth, so the thermostat on the store is placed in a more central
position
than on a normal small hot water cylinder. Because the store should be
pretty constantly charged all the time, it can then be used to dump heat
back into the central heating side to give a rapid sort of boost before
the
actual heating has got up to temperature. That's why the store should be
set and forgotten. It's why this type of storage and heating system is
used, all be it on a larger scale, in most commercial developments now.

Setting the automatic by-pass valve. It is easier to set the by-pass
valve
if you can disconnect the zone valves from the power, but leave the rest
of
the system running as normal.

First, open the zone valves manual and set the system running. The
by-pass
valve should be closed to allow normal operation. Now close both zone
valves and the by-pass valve should open to allow circulation through it.
If it doesn't, then adjust it. If it opens while in normal operation, it
is
to sensitive and also needs adjusted. That's the easy way to set the
by-pass valve.

Have a play around with it all, it can't bite. And have fun with it.

Hey Hey Hey !!! :-) That should say open the zone valves "manually" not
manual. I nearly had you opening the instruction book for the zone valves.
LOL

On Sat, 6 Dec 2008 13:34:31 -0800 (PST) someone who may be pepper
wrote this:-

There is a "hot water" / "heating" programmable timer that operate the
two zone valves, (as per the Gledhill wiring diagram), and a Heatmiser
programmable room stat in the lounge.
There are 50 evacuated solar tubes installed on the roof for the solar
side of things, along with their associated pump, controller etc.

The system is built pretty much as per page 4 of the Gledhill manual;
http://www.gledhill.net/pdfmanuals/B...entRE-Iss3.pdf
(but with no underfloor heating circuit).

The first thing I noticed is that is that the S-Plan wiring diagram
does not appear to entirely correspond with the plumbing in Diagram
1. For example it appears that Diagram 1 shows a heating system
where the temperature of the rooms is controlled entirely by
thermostatic valves, unless the two valves underneath the bypass
valve in the diagram are motorised and it is intended that only one
will be open at any time, in which case the bypass valve is
redundant [1]. Given that I could well be missing something, here
are my thoughts.

I think I'm fairly clear on what needs to happen in the summer; My
idea is to set the "hot water" to come on before sunrise for half an
hour or so, to ensure that the store is adequately charged for morning
ablutions, and then hope that the sun fully charges the store
throughout the day.

You might also like to try not having the boiler on at all in
summer. Enough heat should remain in the store to provide enough hot
water for washing in the morning if it is properly sized and
installed. If on rare occasions it isn't, give the boiler 30 minutes
or so.

The quandry is what to do in the current, wintery climate? The system
is currently wired as per page 9 of the above manual, with the store
thermostat set to 75C, and it seems to me that the problem with this
setup is that the boiler only fires, (and hence the store only heats),
when the room stat calls for heat.

I think the control system shown in that diagram is over-complicated
though I will leave this for the moment and come back to it later.

Following the diagram through it seems to me that if either the
heating or domestic hot water motorised valve is open (which depends
only on their own thermostat) then there will be a signal to fire
the boiler, via contact 10 in the wiring centre, provided it is not
intercepted by the boiler hold-off thermostat. Thus the store
thermostat should bring the boiler on as necessary, which is easy to
test by turning down the heating thermostat and turning up the store
thermostat. If it doesn't then the wiring is not to the diagram.

Is the answer to have the store permanently charged, and just use the
room stat to operate the heating zone valve?

See below.

If you look at the photograph on page 7 of the manual you can see that
the cylinder thermostat is roughly in line with the entering (boiler
flow), hot water. However, the water that is pumped *from* the store
around the heating system comes from, I would guess, 40-50cm below
this stat, and is therefore considerably cooler. Is this right /
normal, and how does it fit in with the rapid-heat-up scenario?

Presumably from the connection marked "28mm compression connection
boiler return (open vented)", which does seem a little low to me.

Finally, can anyone offer any advice as to how to set up the automatic
bypass valve. What kind of figure does it need to be set to, (IIRC
the range is 0.05 to 0.5 bar).

I'm not sure it does anything, but I would set it to 0.5 bar just to
keep it from opening unless necessary. All the other components
should withstand at least 1 bar.

My impression of the plumbing and particularly the wiring is that
these were drawn up by someone with decades of experience in
"conventional" heating systems who then modified their standard
arrangements to allow for the new-fangled thermal store, instead of
starting with an open mind from first principles. As a result they
have ended up with something over-complicated. No-doubt an
interesting challenge to them, but it is not elegant.

This isn't a disaster, but I am going to suggest some modifications
which I think will produce a better system. I'll leave aside the
question of whether you can make them yourself or will need to get
an installer back.


Plumbing

I would separate out the boiler and heating pipework, providing them
each with a pump and doing away with the motorised valves [2] and
bypass valve. The store should be the neutral point, so pumping
would be out of the store, on the return from the store to the
boiler and on the flow from the store to the heating. Assuming all
the connections shown on page 7 are present, but some are blanked
off, I would connect things as follows:

Flow from boiler - 28mm compression connection alternative energy
flow (open vented)

Return to boiler - 28mm compression connection boiler return (open
vented)

Flow to heating - 28mm compression connection boiler flow (open
vented)

Return from heating - 28mm compression connection alternative energy
return (open vented)

This simplifies the plumbing. The connections are not ideal, but
seem to be the best that can be done with the store as it is.

I put the heating return lowest down to make the most of solar.
There is an argument to put the boiler return, from store to boiler,
lowest down to maximise the amount of condensing the boiler does. It
can be argued either way and on another day might I have gone for
that.


Controls

The wiring diagram talks about the DeltaSol BS, but there are four
models of this controller and I would install this setup with either
the BS3 or the BS4 controller. Both of these can control a boiler,
as well as solar.

Assuming the plumbing has been modified as I suggested and a BS3 or
BS4 is used the two port valves, store thermostat and boiler
hold-off thermostat are all exterminated. Instead the solar
controller keeps an eye on the store temperatures via its own
sensors. The solar controller tells the boiler when to fire and the
boiler controls its own pump, which just pumps water round the
boiler circuit as necessary. The solar controller can be told things
like when the boiler should be available, what temperature to warm
the store up to when there is solar output, what temperature to warm
the store up to when there is no solar output and so on. It is all
explained in the "mounting instructions" on
http://www.resol.de/en/english.shtml. In essence the solar
controller controls heat input to the store.

Heat output is controlled by the heating controller. If I was
starting from scratch this would be a single channel controller, but
in this case I would just use the heating side of the existing
controller. This controls the heating pump via the room thermostat
(or thermostats if more than one zone, see [2]).

When heating starts hot water will be taken out of the store. This
will reduce store temperature and eventually the solar controller
will bring the boiler on for some time to re-charge the store, then
it will be off for some time. With the right settings, which will be
a matter of fiddling, the store temperatures will be such that hot
water is still always available. My guess is that as long as the
store temperature is above 50C there will be enough hot water for
anything but a large bath. This will give the long boiler burns you
want.

If the solar controller is a BS1 or BS2 then I would make use of the
existing equipment to do much the same thing. The HW side of the
existing ST6400 controller operates the boiler, via the thermal
store and boiler hold-off thermostats. The heating side of the
controller operates the heating pump via the room thermostat. I am
assuming that the ST6400 provides fully independent times for
heating and hot water. Certainly in winter the store should be
active all day, so that whenever heating depletes the store that
will bring on the boiler.

As solar is location dependent there are no sets of foolproof
numbers to plug in to get ideal performance. It is necessary to
understand and learn to get the best out of it.


[1] I see that there is a feed direct to the pump if one or both of
the motorised valves is open, but in this case the bypass is still
redundant.

[2] Or possibly re-using the motorised valves. They could be used to
provide two zones of heating, each controlled by a local thermostat.
Where these zones are depends on the house and pipework. East/west
or top/ground floor are possible, depending on orientation of the
house and room arrangements. By buying more valves and thermostats
more zones can be created.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On Sun, 07 Dec 2008 17:00:31 +0000 someone who may be David Hansen
wrote this:-

Following the diagram through it seems to me that if either the
heating or domestic hot water motorised valve is open (which depends
only on their own thermostat)

And obviously whether the time clock has enabled the valve or not.

When heating starts hot water will be taken out of the store. This
will reduce store temperature and eventually the solar controller
will bring the boiler on for some time to re-charge the store, then
it will be off for some time.

Obviously domestic hot water draw-off will also decrease the store
temperature and may eventually bring the boiler on. However, this
effect will be much less than that of the heating.



--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

Many thanks Big Wallop and David Hansen,
Much excellent advice to digest there, and I will respond in due
course. I don't think I will be changing any pipework in the
immediate future, (too much other 'stuff' going on), but I think I
understand the immediate change I need to make is to keep the store
charged permanently during the day (during the winter). For the
immediate effect I can just set the "hot water" to be on all day, and
I'll wind the bypass all the way up to 0.5!

David, I need to investigate exactly which solar controller I have.
It is certainly a Resol DeltaSol BS, but I'll have to check which
model when I'm back home - the options presented by models 3 or 4
sound interesting.

I now notice that I don't have the "boiler hold off pipe thermostat"
which is shown attached to the solar pipework in the Gledhill circuit
diagram - I'm not sure what this actually does, and whether I need
such a thing. - any clues?.

Finally, a quick question regarding my boiler. It is a Ferrolli
Optimax 25 OV, which the manual claims the heating temperature "can
be varied from a minimum of 30 °C to a maximum of 90 °C". Mine only
winds up to 80 C, so does anyone know if there is an installer menu,
(press this whilst holding that whilst picking your nose type of
thing), that lets me wind the beast all the way up to the metaphorical
"11"?

On Sun, 7 Dec 2008 13:23:57 -0800 (PST) someone who may be pepper
wrote this:-

David, I need to investigate exactly which solar controller I have.
It is certainly a Resol DeltaSol BS, but I'll have to check which
model when I'm back home

I presume the printed instructions and box say which model it is. If
not there is presumably a "diagnostic" screen on the controller
which shows model number, firmware and so on. Perhaps there is a
label, cunningly fitted to the back so you can't see it when the
controller is fastened to the wall. A triumph of ideas on visual
appearance over usefulness.

I now notice that I don't have the "boiler hold off pipe thermostat"
which is shown attached to the solar pipework in the Gledhill circuit
diagram - I'm not sure what this actually does, and whether I need
such a thing. - any clues?.

Solar heats the store relatively slowly. If there is solar available
then it makes sense to hold off the boiler to give solar a chance to
warm the store up.

Solar controllers which also control boilers can usually be set up
with two set temperatures for boiler heating. One is when solar is
not active, the other is when solar is active and this in effect
sets a minimum floor to store temperature.

I would only fit a separate thermostat to do this if the solar
controller will not control a boiler and you would prefer not to
replace it with one which does.



--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

David,

It looks like I have the 68.03 model of the DeltaSol BS. This model
has two relay outputs, one of which can be used for controlling "after-
heating", (according to the Resol litterature). I am not clear on
exactly how they invisiage this being implemented, or to which of the
four possible sensors the "AH O" and "AH F" settings relate. I am
also not clear on when exactly the second relay is energised... is it
when AH O is exceeded or when the temperature falls below AH O etc
etc? I have emailed Resol with the same question, but if you happen
to already know the answer then your help is once again appreciated.
Mike

On Tue, 9 Dec 2008 16:28:20 -0800 (PST) someone who may be pepper
wrote this:-

It looks like I have the 68.03 model of the DeltaSol BS. This model
has two relay outputs, one of which can be used for controlling "after-
heating", (according to the Resol litterature).

Then you are in luck. It will hold off the boiler if thermal heating
is available.

I can't remember the manual (and you can read it just as well as I
can), but my recollection is that this can be used for two
functions, either controlling a boiler or controlling a heat dump
circuit, depending on the programming. It might even be possible to
control two stores, with one being charged first, but that may be
beyond it.

I am not clear on
exactly how they invisiage this being implemented, or to which of the
four possible sensors the "AH O" and "AH F" settings relate. I am
also not clear on when exactly the second relay is energised... is it
when AH O is exceeded or when the temperature falls below AH O etc
etc?

I don't know the answer. My guess is that it depends on whether it
is programmed as a boiler or a heat dump. If you connect a light
bulb to the output of the second relay then you can play until you
work out how it works.

When you are happy, connect it to the boiler and rationalise the
wiring.

As you are sticking with the same hydraulic arrangements you will
need to work out how to energise the pump when the following
requirements are met:

1) the thermal store is being recharged. Either the motorised valve
direct to the boiler must be open, or the motorised valve round the
heating circuit must be open (called from the second condition)

2) heating is being called for. The motorised valve direct to the
boiler must be closed and the one to the heating system must be
open.

Some conservative people use the solar controller to drive a relay,
which then controls the pump. That reduces the current the solar
controller is switching and thus makes it less likely that the relay
on the controller will fail and an expensive new solar controller
will be needed (or a very fiddly repair on the circuit board).
Obviously don't try and connect a variable speed solar pump output
to a relay, though it would be possible to use a variable speed
output to drive a power transistor or other electronic "relay". Set
the solar output to 100%. There is a school of thought that of/on
control is a better approach for solar, rather than variable speed.
The relative merits probably depend on the length of pipe run and
thus heat losses.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On 10 Dec, 22:16, David Hansen
wrote:

Then you are in luck. It will hold off the boiler if thermal heating
is available.

It seems not - the Resol manual states that "The thermostat function
works *independently* from the
solar operation".
This suggests to me that this second relay output would merely replace
the store thermstat which already controls the boiler. The advantage
however could be that I could set an on/off range thus maximising the
burn time of the boiler, (e.g. boiler heats the store if the temp is
below 65 C, and continues heating until temp reaches 75 C... this
would be similar to installing two store thermostats at slightly
different heights up the cylinder.that I have read about elsewhere).
The interesting thing is that Resol talk about controlling this
'thermostat function' with sensor 3 at the top of the cylinder. - I
can't see how this could be useful, and I think I'd have to make
sensor 3 the half-way-up sensor?

On another issue, this rapidly dumping heat into the heating system
definitely isn't working as I'd hoped. We went away last weekend and
left the room stat in frost mode. When we returned the programmable
room stat (house temperature) said 13C. Top of heat store said ~75C
and bottom of store ~50C (IIRC). Turning on the heating (pump) starts
the process nicely, but within 5 minutes my kitchen plinth heater fan
turned itself off indicating that the temperature of the water in the
pipes had dropped below 40c [room stat barely reached 14C by this
stage]. This is not quite what I'd hoped... it's not a deal breaker,
and could probably be sorted by adding a lower thermostat, but
nevertheless doesn't give me the sooper-dooper quick heat up I'd hoped
for, (and had promised the missus!)

On Wed, 17 Dec 2008 11:53:56 -0800 (PST) someone who may be
wrote this:-

Then you are in luck. It will hold off the boiler if thermal heating
is available.

It seems not - the Resol manual states that "The thermostat function
works *independently* from the solar operation".

I'm surprised, but it is a while since I read the manual,

On another issue, this rapidly dumping heat into the heating system
definitely isn't working as I'd hoped. We went away last weekend and
left the room stat in frost mode. When we returned the programmable
room stat (house temperature) said 13C. Top of heat store said ~75C
and bottom of store ~50C (IIRC). Turning on the heating (pump) starts
the process nicely, but within 5 minutes my kitchen plinth heater fan
turned itself off indicating that the temperature of the water in the
pipes had dropped below 40c

The boiler should have come on by then, though five minutes is a
short time to use up so much of the heat.



--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

"pepper" wrote in message
...
Dear Group,

Following advice from the archives of this group we've had a thermal
store installed to service our house with it's gleaming new extension.
The store is a 350 litre Gledhill Torrent RE Solar in the loft, and a
Ferolli 25OV boiler installed in the loft too.
There is a "hot water" / "heating" programmable timer that operate the
two zone valves, (as per the Gledhill wiring diagram), and a Heatmiser
programmable room stat in the lounge.
There are 50 evacuated solar tubes installed on the roof for the solar
side of things, along with their associated pump, controller etc.

The system is built pretty much as per page 4 of the Gledhill manual;
http://www.gledhill.net/pdfmanuals/B...entRE-Iss3.pdf
(but with no underfloor heating circuit).

What I'm looking for is advice from those who've been there on how to
set up timers, bypass valves etc, so as to best utilise the system.

I think I'm fairly clear on what needs to happen in the summer; My
idea is to set the "hot water" to come on before sunrise for half an
hour or so, to ensure that the store is adequately charged for morning
ablutions, and then hope that the sun fully charges the store
throughout the day.

The quandry is what to do in the current, wintery climate? The system
is currently wired as per page 9 of the above manual, with the store
thermostat set to 75C, and it seems to me that the problem with this
setup is that the boiler only fires, (and hence the store only heats),
when the room stat calls for heat. This means that once the room
temperature has been satisfied then the store may be left only
partially charged, thus potentially compromising the ability to
provide hot-enough DHW. (and IIUC also doesn't help prevent the boiler
cycling that thermal stores are supposed to help with).
Is the answer to have the store permanently charged, and just use the
room stat to operate the heating zone valve?
i.e either set the "hot water" timer to be on whenever the heating
timer is on, or alternatively wire the "heating timer" to operate the
pump/cylinder stat, and have the programmable room stat merely switch
the heating zone valve?
Obviously I also still want to extract as much of the suns meagre
solar offerings as possible, and so the ideal for this is to have as
cool a store as possible... hmmm.

Previous posters have written of the advantages of being able to
rapidly dump heat from the store into the radiators, and hence quickly
heat the home. This is one area that is currently slightly
disappointing.
If you look at the photograph on page 7 of the manual you can see that
the cylinder thermostat is roughly in line with the entering (boiler
flow), hot water. However, the water that is pumped *from* the store
around the heating system comes from, I would guess, 40-50cm below
this stat, and is therefore considerably cooler. Is this right /
normal, and how does it fit in with the rapid-heat-up scenario?

Finally, can anyone offer any advice as to how to set up the automatic
bypass valve. What kind of figure does it need to be set to, (IIRC
the range is 0.05 to 0.5 bar). Are there any tips or 'usual' settings
for this?

Any advice from the several subscribers who have similar systems on
how best to optimise my system is very much appreciated.

Many thanks, Mike H

Mike, the thing about thermal stores is that the individual functions are
quite hydualically separate. The boiler only heats the store. The CH pump
only heats a CH loop, the DHW is separate again. The solar loop is
separate. They have no interaction with each other. The only common point
is the store which is a wonderful neutral point.

To get it to work as you want you will need to change pipework. This is what
you must do.

a) Take the boilers flow to the top alternative energy connection.
b) Take the return of the boiler to the bottom alternative energy
connection.
c) Put the pump on the return to the boiler with a check valve just after
the pump to stop gravity circulation.

d) The current boiler flow, half way up the store, re-direct to the flow of
the rad system loop.
e) The current boiler return, below the flow take to the CH return. Install
on the flow a Wlio Smart auto variable speed pump with check valve in front
of it.
f) Install a Magnaclean filter on the CH return to the store. This is
ESSENTIAL
g) Put TRVs on all rads, the Smart cope with this.
h) Remove the zone valves and by-pass valve.
i) Remove the stat timer in the living area, as TRVs all around

That is the pipework sorted. A normal thermal store setup. The stat is in
the wrong place. Is there a spare cyl stat probe point on the cylinder? Or
is there a spare tapping not used that can be converted to a probe point?
If so, where on the cylinder? A Surrey flange in CH return tapping may be
useful to insert a probe point, so all is not lost. Having two stats will
prevent boiler cycling.

Now, what you have is a boiler that only heats the store. And a CH loop
that only takes heat from the store. The two functions are hydraulically
separate.

There appears to be enough water volume between the CH flow and return
tappings in the store. The average rad system is 100 litres. So it looks
like it can dump 100 litres of hot water in the rads.

If the solar controller has a relay to cut out the boiler when there is
useful solar heat then it "may" be worth wiring that in. Sometime when they
cut out the boiler there is not enough useful solar heat and the store is
too cool. I would be inclined not to play with the boiler and leave it
alone and allow the solar coil to give some pre-heated water at the bottom
of the store.

The main ST 6400 timer can time the store to come on earlier in the morning
via the DHW function, so you have a store of ready hot water to dump into
the rads, when the CH function switches on the CH pump.

Using two stats to prevent boiler cycling requires a relay. It may be wise
to put in CH pump interlock, using spare relay contacts. When the boiler
is reheating the CH pump is cut out.

Over to you.

"Doctor Drivel" wrote in message
...

h) Remove the zone valves and by-pass valve.

You may want to use the redundant zone valves in creating two CH zones, one
upstairs and one down after the pump, and no check valve. Best have a
single stage timer for each. Timer energises the zone valve and the end
switch turns on the pump. Having TRVs all around will require no wall room
stats in the house.

Of course there may be some pipe changes in the CH circuit to create two
zones.

On 7 Dec 2008, 17:00, David Hansen
wrote:
unless the two valves underneath the bypass
valve in the diagram are motorised and it is intended that only one
will be open at any time, in which case the bypass valve is
redundant

David, The two valves are motorised, and I agreed with your idea that
the motorised valve seemed redundant... hence I set it right up to
max.
I've since found it's purpose (!); it of course allows fluid to flow
after both zone valves have closed, but whilst the boiler is still in
it's pump run-on cycle. I was getting a lot of banging and noise
from the boiler - my conclusion is that with the pump on setting 1
there is not enough static pressure to overcome the auto bypass valve
when set on 0.5bar, and hence I was getting local boiling within the
boiler at the end of the call for heat.

On 18 Dec 2008, 11:52, "Doctor Drivel"
wrote:

To get it to work as you want you will need to change pipework. This is what
you must do.

SNIP RECOMMENDED CHANGES


F.A.O. Dr Drivel & David Hansen, (and the rest of the group),

The more I look at the way the store operates, the more I see the
sense and simplicity of the separacity of the boiler and heating
hydraulic systems that you both recommend. Unfortunately I may have
mislead you slightly by referring you to the photo in the boiler
manual, rather than the specific layout of the bosses on my particular
cylinder, so if you have time and patience to look at the following
then I would greatly appreciate it;

My cyclinder is here; http://tinyurl.com/cekdub and
http://tinyurl.com/cprkfy

In case of parallax error in the photos then the connections are at
the following heights (cm) [measured from the bottom]

Solar Coil Return 25
Solar Coil Flow 37

'Boiler' coil (unused) 52
'Boiler' coil (unused) 68

DHW coil in 112
DHW coil out 130

Then there are the following bosses which I believe are all open to
the main body of the cylinder;
27cm = F&E connection
38cm = currently unused (to right in 2nd picture)
53cm = Currently flow to radiators/return to boiler via pump
69cm = currently unused (to right in 2nd picture)
88cm = Currently boiler flow
88cm = Additional unused boss (this is a 28mm boss I think)

Electric Immersion Heater is at 47cm
Cylinder Thermostat is at 75cm
Sensor pocket at 38cm
Sensor pocket at 74cm
Sensor pocket at 130cm

Top of cylinder is 150cm


I'm thinking that your recommendations would be to use the 53cm/88cm
pair of connnections for boiler return/flow
and the 38cm/69cm pair of connections for radiator return/flow - does
that sound about right?


Another couple of questions for the group;

- It has been suggested that I could probably help cut down on
disturbances to the cylinder stratification caused by the pumped fluid
if I connected the boiler flow to a length of perforated copper tube
which is then pushed into the cylinder. The theory being that the
boiler flow would not be such a single 'jet' of water into the
cylinder, but a series of smaller jets spread across a wider area.
.... would it be worth doing this for boiler return / heating flow /
heating return too? - Comments?

- I see Dr Drivel often recommends a twin thermostat (with latch) way
of controlling the heating of the thermal store - I'm thinking I could
use the 'after heat' function of my existing Resol controller to
achieve a similar effect. This function lets me say - "If sensor
temperature falls below x then fire boiler...... keep firing until
temperature y is met". Any comments on this arrangement?

- Dr D also recommends check valves in the system. I don't see how
the valve in his point (e) would work... wouldn't it be in the wrong
direction? - surely to prevent thermosyphoning it would also prevent
normal pumping of the fluid through the heating system? - maybe I
don't understand the check valve correctly.

- Could I plumb in the changes so as to create anti-thermosyphon
traps, (u-bends), and thus do-away with the check valves all together?
[Bear in mind the cylinder & boiler are in the loft and all rads are
on the floors below].

Your help is very much appreciated.

Many thanks,
Mike

On Tue, 3 Feb 2009 15:39:21 -0800 (PST) someone who may be
wrote this:-

I'm thinking that your recommendations would be to use the 53cm/88cm
pair of connnections for boiler return/flow
and the 38cm/69cm pair of connections for radiator return/flow - does
that sound about right?

From a quick skim, that is what I would do.

- It has been suggested that I could probably help cut down on
disturbances to the cylinder stratification caused by the pumped fluid
if I connected the boiler flow to a length of perforated copper tube
which is then pushed into the cylinder. The theory being that the
boiler flow would not be such a single 'jet' of water into the
cylinder, but a series of smaller jets spread across a wider area.
... would it be worth doing this for boiler return / heating flow /
heating return too? - Comments?

Some cylinders/stores are fitted with something similar. If you are
handy and want to try this then it shouldn't take too long to make.

I'm thinking I could
use the 'after heat' function of my existing Resol controller to
achieve a similar effect. This function lets me say - "If sensor
temperature falls below x then fire boiler...... keep firing until
temperature y is met". Any comments on this arrangement?

That is the normal way of doing it. Ideally the temperatures will be
lower if solar output is available.




--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

wrote in message
...
On 18 Dec 2008, 11:52, "Doctor Drivel"
wrote:

To get it to work as you want you will need to change pipework. This is
what
you must do.

SNIP RECOMMENDED CHANGES


F.A.O. Dr Drivel & David Hansen, (and the rest of the group),

The more I look at the way the store operates, the more I see the
sense and simplicity of the separacity of the boiler and heating
hydraulic systems that you both recommend. Unfortunately I may have
mislead you slightly by referring you to the photo in the boiler
manual, rather than the specific layout of the bosses on my particular
cylinder, so if you have time and patience to look at the following
then I would greatly appreciate it;

My cyclinder is here; http://tinyurl.com/cekdub and
http://tinyurl.com/cprkfy

In case of parallax error in the photos then the connections are at
the following heights (cm) [measured from the bottom]

Solar Coil Return 25
Solar Coil Flow 37

'Boiler' coil (unused) 52
'Boiler' coil (unused) 68

DHW coil in 112
DHW coil out 130

Then there are the following bosses which I believe are all open to
the main body of the cylinder;
27cm = F&E connection
38cm = currently unused (to right in 2nd picture)
53cm = Currently flow to radiators/return to boiler via pump
69cm = currently unused (to right in 2nd picture)
88cm = Currently boiler flow
88cm = Additional unused boss (this is a 28mm boss I think)

Electric Immersion Heater is at 47cm
Cylinder Thermostat is at 75cm
Sensor pocket at 38cm
Sensor pocket at 74cm
Sensor pocket at 130cm

Top of cylinder is 150cm

Where are the alternative energy connections as per the Gledhill diagram?

I'm thinking that your recommendations would be to use the 53cm/88cm
pair of connnections for boiler return/flow
and the 38cm/69cm pair of connections for radiator return/flow - does
that sound about right?


Another couple of questions for the group;

- It has been suggested that I could probably help cut down on
disturbances to the cylinder stratification caused by the pumped fluid
if I connected the boiler flow to a length of perforated copper tube
which is then pushed into the cylinder. The theory being that the
boiler flow would not be such a single 'jet' of water into the
cylinder, but a series of smaller jets spread across a wider area.
... would it be worth doing this for boiler return / heating flow /
heating return too? - Comments?

Worth doing. Face the boiler flow upwards towards the DHW coil.

- I see Dr Drivel often recommends a twin thermostat (with latch) way
of controlling the heating of the thermal store - I'm thinking I could
use the 'after heat' function of my existing Resol controller to
achieve a similar effect. This function lets me say - "If sensor
temperature falls below x then fire boiler...... keep firing until
temperature y is met". Any comments on this arrangement?

If it works independently of the solar control then that is fine. Gledhill
do it on the Systemate and Boilermates.

- Dr D also recommends check valves in the system. I don't see how
the valve in his point (e) would work... wouldn't it be in the wrong
direction? - surely to prevent thermosyphoning it would also prevent
normal pumping of the fluid through the heating system? - maybe I
don't understand the check valve correctly.

- Could I plumb in the changes so as to create anti-thermosyphon
traps, (u-bends), and thus do-away with the check valves all together?
[Bear in mind the cylinder & boiler are in the loft and all rads are
on the floors below].

The CH. Have a Smart pump, pump "away" from the cylinder. The flow of the
CH circuit. You could put and anti circulation loop in the pipework.

On 4 Feb, 18:40, "Doctor Drivel" wrote:

The CH. Have a Smart pump, pump "away" from the cylinder. *The flow of the
CH circuit. *You could put and anti circulation loop in the pipework.- Hide quoted text -

As the CH would come out of the cylinder and then head downwards,
(remember cylinder is in loft), then I presume I could get away
without a check valve or anti circulation loop on this circuit?

wrote in message
...
On 4 Feb, 18:40, "Doctor Drivel" wrote:

The CH. Have a Smart pump, pump "away" from the cylinder. The flow of the
CH circuit. You could put and anti circulation loop in the pipework.- Hide
quoted text -

As the CH would come out of the cylinder and then head downwards,
(remember cylinder is in loft), then I presume I could get away
without a check valve or anti circulation loop on this circuit?


A bit iffy. Sometimes you can get circulation through just one rad. I
would put one in to be sure. The check valve is cheap enough or a loop in
the pipe work.

On 5 Feb, 01:51, "Doctor Drivel" wrote:
wrote in message

...
On 4 Feb, 18:40, "Doctor Drivel" wrote:

The CH. Have a Smart pump, pump "away" from the cylinder. The flow of the
CH circuit. You could put and anti circulation loop in the pipework.- Hide
quoted text -

As the CH would come out of the cylinder and then head downwards,
(remember cylinder is in loft), then I presume I could get away
without a check valve or anti circulation loop on this circuit?


A bit iffy. *Sometimes you can get circulation through just one rad. *I
would put one in to be sure. *The check valve is cheap enough or a loop in
the pipe work.

How does that work then? - If the cylinder is in the loft and the rads
are on the floor below then how can thermosyphoning happen there?... I
thought the whole point was that the hot water could only rise?

wrote in message
...
On 5 Feb, 01:51, "Doctor Drivel" wrote:
wrote in message

...
On 4 Feb, 18:40, "Doctor Drivel" wrote:

The CH. Have a Smart pump, pump "away" from the cylinder. The flow of
the
CH circuit. You could put and anti circulation loop in the pipework.-
Hide
quoted text -

As the CH would come out of the cylinder and then head downwards,
(remember cylinder is in loft), then I presume I could get away
without a check valve or anti circulation loop on this circuit?


A bit iffy. Sometimes you can get circulation through just one rad. I
would put one in to be sure. The check valve is cheap enough or a loop in
the pipe work.

How does that work then? - If the cylinder is in the loft and the rads
are on the floor below then how can thermosyphoning happen there?... I
thought the whole point was that the hot water could only rise?


The temp in the rads maybe 23C in summer. A big DHW draw off makes the
bottom of the cylinder 15C. Siphoning then starts.

The return to cylinder. Just have it bending upwards and then loop back
down with a vent on the top. Keep the loop below the flow tapping. This
will stop circulation

On 6 Feb, 11:33, "Doctor Drivel" wrote:
wrote in message

...
On 5 Feb, 01:51, "Doctor Drivel" wrote:





wrote in message

....
On 4 Feb, 18:40, "Doctor Drivel" wrote:

The CH. Have a Smart pump, pump "away" from the cylinder. The flow of
the
CH circuit. You could put and anti circulation loop in the pipework.-
Hide
quoted text -

As the CH would come out of the cylinder and then head downwards,
(remember cylinder is in loft), then I presume I could get away
without a check valve or anti circulation loop on this circuit?


A bit iffy. Sometimes you can get circulation through just one rad. I
would put one in to be sure. The check valve is cheap enough or a loop in
the pipe work.

How does that work then? - If the cylinder is in the loft and the rads
are on the floor below then how can thermosyphoning happen there?... I
thought the whole point was that the hot water could only rise?


The temp in the rads maybe 23C in summer. *A big DHW draw off makes the
bottom of the cylinder 15C. *Siphoning then starts.

The return to cylinder. *Just have it bending upwards and then loop back
down with a vent on the top. *Keep the loop below the flow tapping. *This
will stop circulation- Hide quoted text -

- Show quoted text -

Excellent - my all singing and dancing thermal store could act as 'air
conditioning' in the summer too.... fan 'kin tastic!

wrote in message
...

The temp in the rads maybe 23C in summer. A big DHW draw off makes the
bottom of the cylinder 15C. Siphoning then starts.

The return to cylinder. Just have it bending upwards and then loop back
down with a vent on the top. Keep the loop below the flow tapping. This
will stop circulation- Hide quoted text -

- Show quoted text -

Excellent - my all singing and dancing thermal store could act as 'air
conditioning' in the summer too.... fan 'kin tastic!


You can do that. Put in the CH circuit a plate heat exchanger. Run the cold
mains through the other side of the plate. When hot water is called, the
cold mains water is pre-heated by the radiator water and the rad water
cools, cooling the house. That is, you are clawing some heat to keep the
DHW bills down and cooling at the same time.

In winter it uses the radiator circuit as a thermal store. When DHW is off,
the boiler re-heats the rads ASAP at full belt. Great for combis.

Easy enough to do.