Volt free room stat for baxi combi

[egginyourface]

Ive been asked to connect a room stat to a baxi combi boiler. Im used to connecting standard honeywell thermostat to valiants with 230volt etc.

I opened this boiler and it read (VOLT FREE CONNECTIONS)

At the moment there is a 2 core flex connected in the terminals. The old stat has been disconnected and cant find it...

Do i need a certain type of room stat 24v ac or dc??

many thanks

 

[oldtimer]

Look at your room stat and you will find it has 4 connection 1 live 2 swtchwire 3 neutral 4 earth hold on a thermostat with a neutral but it is a switch well no actually for a standard stat to work it needs a neutral so always run a 3 core and earth not a 2 core and earth.

What happens if you dont run a neutral well your energy bill will go up by 8% years ago who cares but with heating bills hitting £1000-1500 per anum it makes sense to wire it correctly

 

[Des 56]

Volt free connections are a glorified remote pair of switch contacts that complete the circuit that is opened when you remove the bridging link
You could fit a wireless receiver for a remote stat,these can be used to switch 230 volt or volt free
If you hard wire the stat,they are as oldtimer stated sometimes designed to accept the neutral for the accelerator, which as he said, improves its efficiency
Whatever you do,be very carefull not to end up applying 230 volt to these volt free connections,the circuit board wont like it at all

 

[Amp David]

Is a neutral required with a volt free stat?

 

[egginyourface]

Sorry, i dont undersand what you mean.

Do i connect the room stat as normal? permanent live and switch live only difference it 24v?

 

[egginyourface]

All I've got is the supply cable connected to live,neutral and earth in the boiler and a 2core flex coming out from the volt free terminal going to where the old stat was

 

[Amp David]

Term 3 and 4 IIRC.

Its just used as a remote switch

 

[egginyourface]

do i need a particular thermostat?

 

[Amp David]

I've fitted standard Honeywell stats in the past, as supplied with no issues at all.

 

[Des 56]

You can use one of these or similar
Drayton RST4 Room Thermostat (Volt Free Contacts)

Just run a twin from the link

 

[egginyourface]

thanks all