I'd like to install a valve that will cut off the central heating
supply to one zone within my house, at certain times of the day.

The zone I refer to is part of the house that I rent out as a flat.
The tenant works during the day and is at home in the evenings and
weekends. I, on the other hand, live in the main part of the house and
need the heating on 24/7 for most of the winter, as I work from home.
It seems wasteful to supply heating to my tenant when she's not at
home.

Are such valves available? I've seen the simple elctrically-operated
on-off valves, but do they sell them with programmable timers?

If so, and anyone recommend a good-value one?

Thank you

Mike W

Are such valves available? I've seen the simple elctrically-operated
on-off valves, but do they sell them with programmable timers?

It is called a 2 port zone valve and is widely available. You could add one
to your existing system as is, although it is better to full "sub-zone" so
that each zone is completely independent.

Use a programmable thermostat in the flat to control the zone valve. The
microswitch outputs from the valve will only be required if you properly sub
zone using S-Plan-Plus or other arrangements.

Christian.

The message
from Mike W W contains these words:

I'd like to install a valve that will cut off the central heating
supply to one zone within my house, at certain times of the day.

The zone I refer to is part of the house that I rent out as a flat.
The tenant works during the day and is at home in the evenings and
weekends. I, on the other hand, live in the main part of the house and
need the heating on 24/7 for most of the winter, as I work from home.
It seems wasteful to supply heating to my tenant when she's not at
home.

Are such valves available? I've seen the simple elctrically-operated
on-off valves, but do they sell them with programmable timers?

If so, and anyone recommend a good-value one?

I don't know of any programmable valve as such but programmable
thermostats are generally available and it is easy enough to install one
to provide an independent zone. I have a cheap one from screwfix
controlling upstairs and a better one (Danfoss TP75) controlling the
downstairs as I am usually at home all day. Sounds as though you could
do with such a setup yourself as it doesn't make sense to run the house
at the same temperature for 24 hours a day. With the domestic hot water
that makes 3 zones for me but you can, within reason, have as many zones
as you like.

--
Roger Chapman

On Mon, 25 Sep 2006 14:38:16 +0100 someone who may be Mike W W
wrote this:-

The zone I refer to is part of the house that I rent out as a flat.
The tenant works during the day and is at home in the evenings and
weekends.

As has been said, two port valve controlled by a suitable
programmer. Electronic thermostats with PID control are probably
best for this sort of situation.

I, on the other hand, live in the main part of the house and
need the heating on 24/7 for most of the winter, as I work from home.

It seems wasteful to supply heating to your house overnight when
you're sleeping. Since installing cavity wall insulation I have
tended to turn my heating on only for an hour or two in the evening.
The heat is retained enough to get ready the next morning.

It may be worth zoning the main part of the house into that which
you use while working and the rest. Each zone can be controlled
independently.


--
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

It seems wasteful to supply heating to my tenant

Ah - a Rigsby valve ;-)

On Mon, 25 Sep 2006 14:44:50 +0100, "Christian McArdle"
wrote:

Use a programmable thermostat in the flat to control the zone valve.

Thanks to all for the replies. I wasn't aware that zone valves could
be controlled by a programmable thermostat/timers. So, from what you
say, it sounds like I need to make sure I get one with a microswitch
connection. Can anyone recommend one, or suggest what is a reasonable
price to pay? About £60 - £70?

Here is a sketch of my system:
http://tinyurl.com/rg6dp
(excuse the scrappy sketch)

I am planning to insert the programmed zone valve in place of the
stopckock shown for Zone 1 (or perhaps next to it).

If these zone valves don't cost too much, I guess the ideal setup
would be to have one controlling Zone 1 and another for Zone 2. Then
each can be programmed independently to suit the living habits of (a)
me, in the main part of the house, and (b) my tenant, in the rented
part of the house. Comments/advice much appreciated.

Thanks again,

Mike W

Thanks to all for the replies. I wasn't aware that zone valves could
be controlled by a programmable thermostat/timers. Can anyone recommend
one, or suggest what is a reasonable
price to pay? About £60 - £70?

They're pretty much a commodity item. i.e.
http://www.screwfix.com/app/sfd/cat/...00724&id=29099

Programmable stats are more personal preference. They have different
features, appearances and prices.

So, from what you say, it sounds like I need to make sure
I get one with a microswitch connection.

You misunderstand. All 2 port zone valves will have a microswitch output.
However, you'll only need to wire that up if you properly subzone the
system. Remember that if you don't properly subzone, then the tenant's
heating will only come on when BOTH your heating thermostat demands heat and
the tenant's thermostat demands heat. If you have independent control, then
your heating could be entirely off (i.e. you are on holiday) and their
heating will still work.

Christian.

The message
from Mike W W contains these words:

Here is a sketch of my system:
http://tinyurl.com/rg6dp
(excuse the scrappy sketch)

Where do the feed and return ultimately lead to? If to the domestic hot
water how is that controlled?

I am planning to insert the programmed zone valve in place of the
stopckock shown for Zone 1 (or perhaps next to it).

Replace would probably be easier. I am not sure what continuing purpose
the stop cock could have once you have a motorised valve to control the
flow. To completely isolate the zone so it could be drained down
independently would require a stop cock on both legs.

If these zone valves don't cost too much, I guess the ideal setup
would be to have one controlling Zone 1 and another for Zone 2. Then
each can be programmed independently to suit the living habits of (a)
me, in the main part of the house, and (b) my tenant, in the rented
part of the house. Comments/advice much appreciated.

Sorry, no idea of the current price of zone valves but I think they are
well worth the investment. I wouldn't have gone that route otherwise.

--
Roger Chapman

On Mon, 25 Sep 2006 17:44:31 +0100, Roger
wrote:

Where do the feed and return ultimately lead to?

At present, they terminate at one radiator (which is actually not in
Zone 1 or Zone 2) The feed goes into that radiator and the return
comes from it. The boiler does have a by-pass valve too, so that if
all the rads are off, the feed will just by-pass the system and go
directly into the return, whereupon the return water temperature will
shut off the flame and pump. At least, that's how I understand it.

If to the domestic hot
water how is that controlled?

It's a combi boiler. DHW is controlled as per most combi boilers.

I am planning to insert the programmed zone valve in place of the
stopckock shown for Zone 1 (or perhaps next to it).

Replace would probably be easier. I am not sure what continuing purpose
the stop cock could have once you have a motorised valve to control the
flow. To completely isolate the zone so it could be drained down
independently would require a stop cock on both legs.

It occurred to me that I could site the zone valve in the return pipe
for the zone, opposite the stop cock which is in the feed pipe for the
zone. Then I can isolate the zone for draining purposes and plumbing
work etc. Would that be okay?

Thanks,

Mike W

On Mon, 25 Sep 2006 17:14:06 +0100, "Christian McArdle"
wrote:

They're pretty much a commodity item. i.e.
http://www.screwfix.com/app/sfd/cat/...00724&id=29099

Whoo, £30! That's about half the price of the ones I saw advertised
elsewhere. Thank you! Now I don't mind buying two of them!

Programmable stats are more personal preference. They have different
features, appearances and prices.

I already have two of those; I ordered two by mistake once. Now I seem
to have a need for both of them. Good job I never got around to
sending the surplus one back...

Mike W

The message
from Mike W W contains these words:

It occurred to me that I could site the zone valve in the return pipe
for the zone, opposite the stop cock which is in the feed pipe for the
zone. Then I can isolate the zone for draining purposes and plumbing
work etc. Would that be okay?

I can't think of any reason why not off hand. If there is I am sure
someone will be along in a minute to say so.

--
Roger Chapman

On Mon, 25 Sep 2006 18:15:21 +0100, Mike W W wrote:

On Mon, 25 Sep 2006 17:44:31 +0100, Roger
wrote:

Where do the feed and return ultimately lead to?

At present, they terminate at one radiator (which is actually not in
Zone 1 or Zone 2) The feed goes into that radiator and the return
comes from it. The boiler does have a by-pass valve too, so that if
all the rads are off, the feed will just by-pass the system and go
directly into the return, whereupon the return water temperature will
shut off the flame and pump. At least, that's how I understand it.

If to the domestic hot
water how is that controlled?

It's a combi boiler. DHW is controlled as per most combi boilers.

I am planning to insert the programmed zone valve in place of the
stopckock shown for Zone 1 (or perhaps next to it).

Replace would probably be easier. I am not sure what continuing purpose
the stop cock could have once you have a motorised valve to control the
flow. To completely isolate the zone so it could be drained down
independently would require a stop cock on both legs.

It occurred to me that I could site the zone valve in the return pipe
for the zone, opposite the stop cock which is in the feed pipe for the
zone. Then I can isolate the zone for draining purposes and plumbing
work etc. Would that be okay?

Zone valves are not bi-directional but you can fit them (the right way
round) in both the flow or return. However they are not intended to act as
absolute stop valves. You would be better to install a pair of full bore
1/4 turn lever valve (also from screwfix) in the heating pipes to the flat
for that purpose.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards