Hi all,

Just planning for conservatory self-build for which I'm sure there
will be many questions over the following weeks!

After much googling of uk.d-i-y it seems that extending the CH
pipework into the conservatory and plumbing into a decent finned
double rad is the way to go. The conservatory rad needs to be
controlled separately from the rest of the houses' CH as I may need
heat in the conservatory during periods when the main house stat is
not demanding heat and the boiler is therefore inactive.

Boiler is an ariston microgenus II31 combi. Control is by a battery
powered 2 wire programmable stat. Zoning is beyond my current level
of knowledge but I'm trying to plug that particular gap right now!
I'm guessing that I need to introduce a 3-port mid position valve to
the flow end of the CH and connect to it (a) the original house stat
and (b) a new stat to be located in the conservatory. The resulting 4
peices of wire (and this is where it gets a bit beyond me) I'm
guessing need to be connected to the valve in a configuration such
that continuity across circuit (a) opens the valve to position a,
circuit (b) opens to position b and (a and b) opens a+b. I think I'm
correct in understanding that the valve will also act as a relay so
that a single connection from the valve to the boiler can be used to
tell the boiler that CH heat is being demanded.

I wonder if anyone could confirm (or not) that I'm barking up the
right tree here. The bit I need further information on is the wiring.
Does anyone have any good pointers to where I may learn about this?

Thanks

Mike

On Fri, 30 Sep 2005 23:53:42 GMT, Army
scrawled:

I'm guessing that I need to introduce a 3-port mid position valve to
the flow end of the CH

You guessed wrong! You want 2 2 port valves in the flow below the
boiler, or before the first tee off, for the house and conservatory
zones.

I wonder if anyone could confirm (or not) that I'm barking up the
right tree here. The bit I need further information on is the wiring.
Does anyone have any good pointers to where I may learn about this?

The wiring is much simplified doing it the correct way! The house stat
controls the valve for the house heating, the conservatory stat
controls the valve for the conservastory heating. The 2 sets of
auxilary contacts control the boiler.
--
Stuart @ SJW Electrical

Please Reply to group

"Lurch" wrote in message
news
On Fri, 30 Sep 2005 23:53:42 GMT, Army
scrawled:

I'm guessing that I need to introduce a 3-port mid position valve to
the flow end of the CH

You guessed wrong! You want 2 2 port valves in the flow below the
boiler, or before the first tee off, for the house and conservatory
zones.

I wonder if anyone could confirm (or not) that I'm barking up the
right tree here. The bit I need further information on is the wiring.
Does anyone have any good pointers to where I may learn about this?

The wiring is much simplified doing it the correct way! The house stat
controls the valve for the house heating, the conservatory stat
controls the valve for the conservastory heating. The 2 sets of
auxilary contacts control the boiler.

That's how mine works (except I have 5 2 port valves).

Wouldn't it work by just parallel wiring a new thermostat assuming the OP
has TRVs on all the radiators?

On Sat, 01 Oct 2005 07:09:49 GMT, "dennis@home"
scrawled:

Wouldn't it work by just parallel wiring a new thermostat assuming the OP
has TRVs on all the radiators?

No, because the 2 stats will not do the job they are intended, in
fact, I'm not really clear on exactly what you're suggesting but it
won't won't work anyway.
--
Stuart @ SJW Electrical

Please Reply to group

"Lurch" wrote in message
...
On Sat, 01 Oct 2005 07:09:49 GMT, "dennis@home"
scrawled:

Wouldn't it work by just parallel wiring a new thermostat assuming the OP
has TRVs on all the radiators?

No, because the 2 stats will not do the job they are intended, in
fact, I'm not really clear on exactly what you're suggesting but it
won't won't work anyway.

If you have TRVs on all the radiators then all you need to know is if the
conservatory needs heat.
If it does you fire the boiler.
You do this by putting a second stat in parallel with the room stat.
In fact you could have several stats if the layout needs it.

I think its a bodge but TRVs are a bodge anyway.

In an earlier contribution to this discussion,
dennis@home wrote:


If you have TRVs on all the radiators then all you need to know is if
the conservatory needs heat.
If it does you fire the boiler.
You do this by putting a second stat in parallel with the room stat.
In fact you could have several stats if the layout needs it.

I think its a bodge but TRVs are a bodge anyway.

Yes, but don't forget that the room in the house where the original room
stat is located *won't* (or *shouldn't* at any rate!) have a TRV on its
radiator. Using your system, that rad will get hot when the boiler fires to
heat the conservatory - even if the rest don't.

Also - unless the conservatory rad has a TRV - which will fight with its
room stat if it *does* - the conservatory will get heated when the rest of
the house is being heated, even if not required.

Positive zoning using motorised valve(s) would be far better - and would
almost certainly be *required* if the setup needs to meet current building
regs. Your solution is a recipe for heating *everything* whenever *anything*
needs heating!
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

In an earlier contribution to this discussion,
Army wrote:

Zoning is beyond my current level
of knowledge but I'm trying to plug that particular gap right now!
I'm guessing that I need to introduce a 3-port mid position valve to
the flow end of the CH and connect to it (a) the original house stat
and (b) a new stat to be located in the conservatory.

You *could* do it with a 3-port valve but, as others have said, you'd be
better off with two 2-port valves.

Have a look at the 'plans' and their associated wiring diagrams in
http://content.honeywell.com/uk/homes/systems.htm

None of them exactly match your setup - but you should get some clues.

The Y-Plan is the one with the 3-port mid-position valve. It is intended to
give independent control of HW and CH in a setup with stored hot water,
rather than a combi. Note that the tank stat in the HW circuit has a
changeover switch with 3 contacts rather than a simple on/off switch. If you
use this setup to control two heating zones rather than HW + CH, it *will*
work - but whichever heating zone is in place of HW *must* have a changeover
thermostat.

The S-Plan (and S-Plan-Plus) are the ones which use 2-port valves. You can
have as many zones as you like, with one valve per zone. The motor of each
valve is controlled by a timer and stat for the appropriate zone or, even
better, by a programmable stat. The secondary contacts on each valve - which
close when the valve opens - are all connected in parallel and used to fire
up the boiler and run the pump whenever one or more valves are open. The
S-Plan shown in the Honeywell diagram (see URL above) shows a HW zone and a
CH zone - but will work just as well for two heating zones.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

In article , Army
writes

I wonder if anyone could confirm (or not) that I'm barking up the
right tree here. The bit I need further information on is the wiring.
Does anyone have any good pointers to where I may learn about this?

In case you were in any doubt, the advice of Mr Square, supported by Mr
Lurch is sound, the other is er, not :-).
--
fred

In an earlier contribution to this discussion,
fred wrote:

In article , Army
writes

I wonder if anyone could confirm (or not) that I'm barking up the
right tree here. The bit I need further information on is the
wiring. Does anyone have any good pointers to where I may learn
about this?

In case you were in any doubt, the advice of Mr Square, supported by
Mr Lurch is sound, the other is er, not :-).

Indeed, in my post of 5:16pm on 1st October, I gave a reference to a
Honeywell site showing various heating plans with their associated wiring
diagrams, and explained that and S-Plan arrangement would be best - but also
explained how a Y-Plan could be adapted to suit the OP's needs if he really
wants to use a 3-port valve.

This information should be sufficient to enable any competent DIY-er to sort
out the wiring.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

"Set Square" wrote in message
...
In an earlier contribution to this discussion,
fred wrote:

In article , Army
writes

I wonder if anyone could confirm (or not) that I'm barking up the
right tree here. The bit I need further information on is the
wiring. Does anyone have any good pointers to where I may learn
about this?

In case you were in any doubt, the advice of Mr Square, supported by
Mr Lurch is sound, the other is er, not :-).

Indeed, in my post of 5:16pm on 1st October, I gave a reference to a
Honeywell site showing various heating plans with their associated wiring
diagrams, and explained that and S-Plan arrangement would be best - but
also
explained how a Y-Plan could be adapted to suit the OP's needs if he
really
wants to use a 3-port valve.

This information should be sufficient to enable any competent DIY-er to
sort
out the wiring.

You could have done it better:-

Find somewhere to break into the flow from the boiler.
Tee in two zone valves one to feed the original circuit.
One to feed the conservatory.

Fit a bypass pipe between the flow and the return before the zone valves
(very important on most systems!).

Wire the room stat to the one valve.
Wire a new room stat to the valve for the conservatory.

Take a live feed to the end switches on the valves and wire the other
terminals to boiler on.

Now don't forget that you need to be an certificating electrician to do it
legally.

In article , Set Square
writes
In an earlier contribution to this discussion,
fred wrote:

In article , Army
writes

I wonder if anyone could confirm (or not) that I'm barking up the
right tree here. The bit I need further information on is the
wiring. Does anyone have any good pointers to where I may learn
about this?

In case you were in any doubt, the advice of Mr Square, supported by
Mr Lurch is sound, the other is er, not :-).

This information should be sufficient to enable any competent DIY-er to sort
out the wiring.

Indeed, but methinks you are now being well & truly trolled :-/.
--
fred

In an earlier contribution to this discussion,
fred wrote:

In article , Set Square
writes
In an earlier contribution to this discussion,
fred wrote:

In article , Army
writes

I wonder if anyone could confirm (or not) that I'm barking up the
right tree here. The bit I need further information on is the
wiring. Does anyone have any good pointers to where I may learn
about this?

In case you were in any doubt, the advice of Mr Square, supported by
Mr Lurch is sound, the other is er, not :-).

This information should be sufficient to enable any competent DIY-er
to sort out the wiring.

Indeed, but methinks you are now being well & truly trolled :-/.

Your right - I'm opting out - this bloke dennis@home has *got* to be a mate
of Dr Drivel - if not an alias! Life's too short to waste any more time
refuting his ramblings.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

"Set Square" wrote:

Your right - I'm opting out - this bloke dennis@home has *got* to be a mate
of Dr Drivel - if not an alias! Life's too short to waste any more time
refuting his ramblings.

I had my doubts before over him, but then again I suspect everyone
(except me!)


--

On Mon, 03 Oct 2005 19:54:29 GMT, fred scrawled:

Indeed, but methinks you are now being well & truly trolled :-/.

Not from this angle he's not.
--
Stuart @ SJW Electrical

Please Reply to group

On Mon, 3 Oct 2005 11:31:30 +0100, "Set Square"
wrote:

In an earlier contribution to this discussion,
fred wrote:

In article , Army
writes

I wonder if anyone could confirm (or not) that I'm barking up the
right tree here. The bit I need further information on is the
wiring. Does anyone have any good pointers to where I may learn
about this?

In case you were in any doubt, the advice of Mr Square, supported by
Mr Lurch is sound, the other is er, not :-).

Indeed, in my post of 5:16pm on 1st October, I gave a reference to a
Honeywell site showing various heating plans with their associated wiring
diagrams, and explained that and S-Plan arrangement would be best - but also
explained how a Y-Plan could be adapted to suit the OP's needs if he really
wants to use a 3-port valve.

This information should be sufficient to enable any competent DIY-er to sort
out the wiring.

Hi Set Square, Lurch et all,

OP here, many thanks for all your helpful posts!

Set Square, your post at 17:16 on Oct-01 was very helpful thank you,
in particular your reference to the honeywell site was really usefull.
I've studied the wiring diagrams and that side of things is fairly
clear now. In order to further my education, a couple of questions
spring to mind if I may be so bold...

(1) Why is S-plan favoured over y-plan? Y Plan seems to be
considerably cheaper to implement (assuming a changeover stat is not
overly expensive) and neater (ie less clutter under the boiler and
disruption to pipework). Also, regarding failures, the Y plan is
never 'closed' so no chance of the pump being activated when both
circuits are off. (Clearly the boiler has a bypass if the above were
to occur on the s-plan). I guess I must be missing something here.

(2) What is a changeover stat?

(3) Why can the motorised valve(s) not be installed on the return
rather than the flow?

BTW, I don't have TRVs on any of the rads. We have lived in this
house for a year now and the system seems to hang together quite
nicely without them. In addition, most of the rads have microbore
into 'same-end' rad valves and I don't think I've seen TRVs in that
configuration before.

Thanks all


Mike

In an earlier contribution to this discussion,
Army wrote:


Hi Set Square, Lurch et all,

OP here, many thanks for all your helpful posts!

Set Square, your post at 17:16 on Oct-01 was very helpful thank you,
in particular your reference to the honeywell site was really usefull.
I've studied the wiring diagrams and that side of things is fairly
clear now. In order to further my education, a couple of questions
spring to mind if I may be so bold...

(1) Why is S-plan favoured over y-plan? Y Plan seems to be
considerably cheaper to implement (assuming a changeover stat is not
overly expensive) and neater (ie less clutter under the boiler and
disruption to pipework). Also, regarding failures, the Y plan is
never 'closed' so no chance of the pump being activated when both
circuits are off. (Clearly the boiler has a bypass if the above were
to occur on the s-plan). I guess I must be missing something here.

The actuator used used on a 3-port mid-position valve is quite complicated
in terms of internal components and micro-switches and is prone to failure.
[A high percentage of central heating problems discussed in this NG can be
laid at the door of the 3-port valve!]

By comparison, a 2-port valve is simpler, and less prone to fail - and also
doesn't represent a single point of failure for the whole system in the way
which the 3-port valve does. In addition - maybe not of interest to you -
it's easy to extend an S-Plan system for multiple zones - whereas a Y-Plan
system can only handle 2 zones, one of which is *usually* hot water.

Sure, an S-Plan system may require a by-pass - but that's easy enough to
implement with an automatic by-pass valve. You may, in fact, also need one
on a Y-Plan system if you have TRVs on all (or virtually) all rads because -
although the valve always provides a path, this may be closed off by TRVs.

(2) What is a changeover stat?

Its a stat whose switch has 3 contacts - common (COM), normally closed (NC)
and normally open (NO). At temperatures below the stat setting, COM is
connected to NC. When the set temperature is reached, the contacts 'change
over' so that COM is then connected to NO. So, instead of simply switching
off when the demand is satisfied, it directs the input voltage somewhere
else instead. In a Y-Plan system, the cylinder stat - in one position -
switches the boiler directly. In the other position, it supplies power to
the 3-port valve - enabling that to switch the boiler via one of its
internal micro-switches when the conditions are right.

(3) Why can the motorised valve(s) not be installed on the return
rather than the flow?

As far as I know it can. Did someone say it couldn't?

BTW, I don't have TRVs on any of the rads. We have lived in this
house for a year now and the system seems to hang together quite
nicely without them. In addition, most of the rads have microbore
into 'same-end' rad valves and I don't think I've seen TRVs in that
configuration before.

Thanks all

Good luck with your conservatory!
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

"Set Square" wrote in message
...

(3) Why can the motorised valve(s) not be installed on the return
rather than the flow?

As far as I know it can. Did someone say it couldn't?


Isn't it because the flow is supposed to go into the centre port.
So if you join two returns back into one the valve is working backwards.
Doesn't this make them liable to stick as the flow is working against the
springs/actuators?

Maybe the OP didn't mean joining two returns into one?


If you going to use valves use 2 port ones with end switches.
Then the whole thing is much easier to wire.
You just parallel up the end switches, connect one side to a live feed (not
the output from the stat!) and the other to boiler on.
Then you connect the thermostats for each zone to the motor on the valves.
You can put a timer in series with each stat if you want (that's all a
combined timer+stat is).

There are two types of 2 port valves.

The most common are spring return.. these open when you power the motor and
close when you stop powering it.

The other type needs power to close and uses a changeover stat to provide
power to open or close as required, this looks complicated but it isn't.
(It can save electricity but not a lot and it needs two live feeds from the
stat.)

BTW the plans are there because most *plumbers* wouldn't be able to do it
without the plan but its all basic logic really.

On Tue, 4 Oct 2005 01:15:16 +0100, "Set Square"
wrote:

In an earlier contribution to this discussion,
Army wrote:


Hi Set Square, Lurch et all,

OP here, many thanks for all your helpful posts!

Set Square, your post at 17:16 on Oct-01 was very helpful thank you,
in particular your reference to the honeywell site was really usefull.
I've studied the wiring diagrams and that side of things is fairly
clear now. In order to further my education, a couple of questions
spring to mind if I may be so bold...

(1) Why is S-plan favoured over y-plan? Y Plan seems to be
considerably cheaper to implement (assuming a changeover stat is not
overly expensive) and neater (ie less clutter under the boiler and
disruption to pipework). Also, regarding failures, the Y plan is
never 'closed' so no chance of the pump being activated when both
circuits are off. (Clearly the boiler has a bypass if the above were
to occur on the s-plan). I guess I must be missing something here.

The actuator used used on a 3-port mid-position valve is quite complicated
in terms of internal components and micro-switches and is prone to failure.
[A high percentage of central heating problems discussed in this NG can be
laid at the door of the 3-port valve!]

By comparison, a 2-port valve is simpler, and less prone to fail - and also
doesn't represent a single point of failure for the whole system in the way
which the 3-port valve does. In addition - maybe not of interest to you -
it's easy to extend an S-Plan system for multiple zones - whereas a Y-Plan
system can only handle 2 zones, one of which is *usually* hot water.

Sure, an S-Plan system may require a by-pass - but that's easy enough to
implement with an automatic by-pass valve. You may, in fact, also need one
on a Y-Plan system if you have TRVs on all (or virtually) all rads because -
although the valve always provides a path, this may be closed off by TRVs.

OK, S-Plan it is then. The only downside to me is that, as both
valves will be living in the space between the (wall mounted) boiler
and the kitchen worktop, I may have to redo my nice neat boxing in to
create some more space. The boiler has an automatic bypass within the
casing and in any case, there are no TRVs on the system at all. I
suppose that the cost difference between 2 2-port valves and 1 3-port
valve is pretty insignificant in the grander scheme of things.

(2) What is a changeover stat?

Its a stat whose switch has 3 contacts - common (COM), normally closed (NC)
and normally open (NO). At temperatures below the stat setting, COM is
connected to NC. When the set temperature is reached, the contacts 'change
over' so that COM is then connected to NO. So, instead of simply switching
off when the demand is satisfied, it directs the input voltage somewhere
else instead. In a Y-Plan system, the cylinder stat - in one position -
switches the boiler directly. In the other position, it supplies power to
the 3-port valve - enabling that to switch the boiler via one of its
internal micro-switches when the conditions are right.

(3) Why can the motorised valve(s) not be installed on the return
rather than the flow?

As far as I know it can. Did someone say it couldn't?


http://content.honeywell.com/uk/home...on%20Guide.PDF

Page 2, on the right, about half way down. I just noticed that this
is refering to the Y-Plan. The S-Plan makes no mention of this
limitation so perhaps S-Plan is OK to fit on the return.



BTW, I don't have TRVs on any of the rads. We have lived in this
house for a year now and the system seems to hang together quite
nicely without them. In addition, most of the rads have microbore
into 'same-end' rad valves and I don't think I've seen TRVs in that
configuration before.

Thanks all

Good luck with your conservatory!

Thanks!


Mike