On advice I've just purchased a a Drayton RF3 wireless room thermostat for
my CH system that was previously controlled by radiator TRVs and timed by a
Tempus Seven Programmer.

I'm not sure if
1. the Drayton RF3 should totally replace the programmer and be left to
control HW and CH.

2. Or should I leave the programmer to control the HW and put the thermostat
in series with the programmer for the CH and just leave it on the ON
position so that the room thermostat controls the CH.

I think option 2 makes sense?

How would this be wired in?

Many Thanks

I have just added a picture of the CH system and wiring box if thats any
help?
http://mysite.wanadoo-members.co.uk/...dpolos/ch1.JPG
http://mysite.wanadoo-members.co.uk/...dpolos/ch2.JPG

"DW" wrote in message
...
On advice I've just purchased a a Drayton RF3 wireless room thermostat for
my CH system that was previously controlled by radiator TRVs and timed by
a Tempus Seven Programmer.

I'm not sure if
1. the Drayton RF3 should totally replace the programmer and be left to
control HW and CH.

2. Or should I leave the programmer to control the HW and put the
thermostat in series with the programmer for the CH and just leave it on
the ON position so that the room thermostat controls the CH.

I think option 2 makes sense?

How would this be wired in?

Many Thanks

In an earlier contribution to this discussion,
DW wrote:

On advice I've just purchased a a Drayton RF3 wireless room
thermostat for my CH system that was previously controlled by
radiator TRVs and timed by a Tempus Seven Programmer.

I'm not sure if
1. the Drayton RF3 should totally replace the programmer and be left
to control HW and CH.

2. Or should I leave the programmer to control the HW and put the
thermostat in series with the programmer for the CH and just leave it
on the ON position so that the room thermostat controls the CH.

I think option 2 makes sense?

How would this be wired in?

Many Thanks

Definitely Option 2 - it makes no sense for the room stat to control the hot
water!

From the pictures in your other post, it's pretty clear that you've got an
S-Plan system - with separate 2-port valves for CH and HW. The the CH side
of the programmer currently controls the CH valve , and the HW side controls
the HW valve. The secondary contacts on both valves turn on the boiler and
pump whenever either valve is open.

So the CH feed from the programmer needs to go to the programmable stat and
then on to the valve motor - rather than going directly to the motor, as at
present. On the orginal programmer, leave CH on constant and do the *actual*
timing with the programmable stat.

The HW side of the original programmer will continue to control the hot
water. Have you got a cylinder stat? If not, you *should* have one in series
with the feed to the HW valve's motor.

See S-Plan in http://content.honeywell.com/uk/homes/systems.htm
--
Cheers,
Set Square
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"Set Square" wrote in message
...
In an earlier contribution to this discussion,
DW wrote:

On advice I've just purchased a a Drayton RF3 wireless room
thermostat for my CH system that was previously controlled by
radiator TRVs and timed by a Tempus Seven Programmer.

I'm not sure if
1. the Drayton RF3 should totally replace the programmer and be left
to control HW and CH.

2. Or should I leave the programmer to control the HW and put the
thermostat in series with the programmer for the CH and just leave it
on the ON position so that the room thermostat controls the CH.

I think option 2 makes sense?

How would this be wired in?

Many Thanks

Definitely Option 2 - it makes no sense for the room stat to control the
hot
water!

From the pictures in your other post, it's pretty clear that you've got an
S-Plan system - with separate 2-port valves for CH and HW. The the CH side
of the programmer currently controls the CH valve , and the HW side
controls
the HW valve. The secondary contacts on both valves turn on the boiler and
pump whenever either valve is open.

So the CH feed from the programmer needs to go to the programmable stat
and
then on to the valve motor - rather than going directly to the motor, as
at
present. On the orginal programmer, leave CH on constant and do the
*actual*
timing with the programmable stat.

The HW side of the original programmer will continue to control the hot
water. Have you got a cylinder stat? If not, you *should* have one in
series
with the feed to the HW valve's motor.

See S-Plan in http://content.honeywell.com/uk/homes/systems.htm
--
Cheers,
Set Square
______

Thanks Set Square.
Yes I do have a cylinder thermostat but not really sure how its wired in....
goes into wiring box pictured anyway.
So looking at the wiring diagram pictured for the thermostat I've ordered:
http://www.invensyscontrolseurope.co...tat3i_RF3i.pdf
It looks like I will just need to wire in the SCR Receiver to the Live
(Brown) and Neutral (Blue) and then what for 1, 2, 3? What colours should
common, heat satisfied and call for heat be? I presume I don't need to
change any of the wiring to the CH 2 port valve?

In an earlier contribution to this discussion,
DW wrote:


Thanks Set Square.
Yes I do have a cylinder thermostat but not really sure how its wired
in.... goes into wiring box pictured anyway.
So looking at the wiring diagram pictured for the thermostat I've
ordered:

http://www.invensyscontrolseurope.co...tat3i_RF3i.pdf
It looks like I will just need to wire in the SCR Receiver to the
Live (Brown) and Neutral (Blue)
Yes

and then what for 1, 2, 3? What
colours should common, heat satisfied and call for heat be? I presume
I don't need to change any of the wiring to the CH 2 port valve?

You need to find the wire which goes from the CH ON connection in the
original programmer to the motor live connnection in the CH 2-port valve
(probably brown - but you'll have to find the *right* brown wire by tracing
it. In effect, you need to cut this wire in half and connect one of the cut
ends to 1 (common) in the SCR receiver and the other cut end to 3 (call for
heat). Don't connect anything to 2 (demand satisfied) - that's only needed
in special cases, or for switching cooling rather than heating equipment.

Provided the volt-free contacts in your motorised valves are connected as
per the S-Plan diagram in the Honeywell reference which I cited earlier,
boiler and pump control will take care of themselves once you have put you
new stat in series with the motor feed.

One other thing which I should have said last time: If you've got TRVs on
all your rads, you need to disable the one on the radiator nearest to your
new room stat - otherwise the TRV could turn the rad off before the room
stat gets a chance to work. Simply removing the thermostatic head off the
valve will do.
--
Cheers,
Set Square
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