wireless thermostat digistat+RF

[Phillip1]

Hi people
I have purchased a wireless digstat+RF to replace my wired stat as I need to control a nursary not the stair well

The old wired honeywell room stat has 3 wires L, N and yellow on 3 call for heat

The RF603 wiring diagram states L, N 1common 2 cooling 3 heat.

I have not connected up yet but have a concern that the common shows an internal voltfree contact between 2 (satified) and 3 Call for heat.

L and N easy, common? does my old yellow wire go to 3?

Help would be appreciated
Phill

 

[twgas]

It appears, to me, that you intend to put the receiver where the old room 'stat was. As the receiver needs a permanent live it should go near the timer/wiring centre/boiler, depending on what type of system and boiler you have.

 

[D_Hailsham]

It appears, to me, that you intend to put the receiver where the old room 'stat was. As the receiver needs a permanent live it should go near the timer/wiring centre/boiler, depending on what type of system and boiler you have.

If you move the CH ON wire to the L terminal of the existing timer/programmer, you can put the receiver where the old stat was.

 

[Phillip1]

If you move the CH ON wire to the L terminal of the existing timer/programmer, you can put the receiver where the old stat was

I don't understand the need to change the wiring in the timer/programmer

The programmer is beside the boiler, which is a potterton suprema,

The room stat I want to replace is 20 feet away in the hall.

The old room stat has live and neutral at 240 volts all the time the boiler is switched on

The yellow wire from the old stat on pin 3 runs up to the wiring box and connects to the mid position value, which when the stat asks for heat is at 240 volts

It looks easy to link the live and common in the receiver to have 240 volts available for the heat/no heat contacts

My concern with this is the diagram with the 'Iflo' kit states the contacts are -"volt free contacts"
Will putting 240 volts through them damage the receiver?

 

[twgas]

It appears, to me, that you intend to put the receiver where the old room 'stat was. As the receiver needs a permanent live it should go near the timer/wiring centre/boiler, depending on what type of system and boiler you have.

If you move the CH ON wire to the L terminal of the existing timer/programmer, you can put the receiver where the old stat was.

that's ok if the 'stat is programmable, if not it's not such a clever idea.

 

[ChrisR]

Phil, the apparently "live" wire going to the old thermostat would probably have come via the CH-ON output in the programmer, not the boiler live direct, hence the need to link out the programmer's CH switch.

[SOme boilers are fussy, and must not be supplied with 230V on the "switched live" (= go) wire, they have to have a dedicated volt free switch doing it , connected to some supply in the boiler (which could eg be low voltage DC). That's why the receiver does have a VF connection. ]

As you're dealing with motorised valves, which work with the mains, yes you can link common to live.

 

[D_Hailsham]

that's ok if the 'stat is programmable, if not it's not such a clever idea.

I had forgotten it was not a programmable stat.

 

[D_Hailsham]

If you move the CH ON wire to the L terminal of the existing timer/programmer, you can put the receiver where the old stat was

I don't understand the need to change the wiring in the timer/programmer

Forget what I wrote; I was thinking you had a programmable thermostat.

The programmer is beside the boiler, which is a potterton suprema

Mount the receiver near the boiler taking into account the manufacturers instructions about location.

The old room stat has live and neutral at 240 volts all the time the boiler is switched on

The cable to the old stat will be redundant.

You need to run a cable from the programmer to the receiver:

Prog Live to Digistat Live
Prog Neutral to Digistat Neutral
Prog CH ON to Digistat 1 (Common)
Digistat 2 (ON) to midpos valve (ie where the yellow wire connected)

Volt free contacts just means that they do not automatically have 240v on them; you have to supply it, if required.

 

[Phillip1]

Phil, the apparently "live" wire going to the old thermostat would probably have come via the CH-ON output in the programmer, not the boiler live direct, hence the need to link out the programmer's CH switch.

I have tried to investigate the wiring further and I see that the call to CH-on wire at the programmer end is connected in the wiring box in the airing cupboard to the live from the downstairs room stat
When the programmer/timer calls for heat the live feed becomes 240 to the room stat which if satisfied holds the volts until the temperature falls below the setting set. Then the volts go up to the mid-valve switch.

I cannot see the need to link out the CH-on switch at the boiler programmer or there will be no voltage at the airing cupboard to get to the stat


As you're dealing with motorised valves, which work with the mains, yes you can link common to live.

I think this is the advice I am going with as another reply explains the meaning of the 'volts free contacts' and I can see that the 240 volts does not go back to the boiler only to the mid-position value
I intend to get this done this week sometime so that any fireworks can be con strued as guy fawkes doing and blamed on him

 

[Phillip1]

If you move the CH ON wire to the L terminal of the existing timer/programmer, you can put the receiver where the old stat was

I don't understand the need to change the wiring in the timer/programmer

Forget what I wrote; I was thinking you had a programmable thermostat.

The programmer is beside the boiler, which is a potterton suprema

Mount the receiver near the boiler taking into account the manufacturers instructions about location.

The old room stat has live and neutral at 240 volts all the time the boiler is switched on

The cable to the old stat will be redundant.

You need to run a cable from the programmer to the receiver:

Prog Live to Digistat Live
Prog Neutral to Digistat Neutral
Prog CH ON to Digistat 1 (Common)
Digistat 2 (ON) to midpos valve (ie where the yellow wire connected)

Volt free contacts just means that they do not automatically have 240v on them; you have to supply it, if required.

Thanks for the above explaination it makes sense to me now

You will see from a reply to the post above that I have investigated further where the 240 volts come from at the old room stat.
I intend to link the live and common so that the contacts have a feed available when the temperature drops below the setting, this will feed the mid-position valve and move it as it does now to the heat position or mid position if both water and heat are called for.
I think I may have water priority in the programmer but this will not be affected.
Watch this space for a satisfactory outcome and thanks for the advice.