Cheap wireless thermostat for Baxi 80e combi

[londonbluefish]

Hi,

Currently in a house with a Baxi 80e combi boiler, which presumably at one time was connected to the Honeywell T6360B thermostat.

At present the wire has been severed between the boiler and the thermostat, and the internal link between terminals 1 and 2 on the boiler has been connected hence CH is always on when the fitted mechanical timer is set ON.

Don't want the hassle of ripping out and replacing cables for a wired thermostat so looking at wireless. However, I am a little confused on some (such as the Salus RT500RF) which requires not only the link from the boiler but also its own power supply.

I had hoped to simply fit the live and switched live to terminals 1 and 2 respectively, thinking that the wireless receiver then by nature always has 230VAC power, and of course removing the internal link between terminals 1 and 2. If this isn't the case then I don't have an easy way to introduce the additional L and N the receiver seems to need.

The Salus RT500RF has terminals listed thus:
1 NO Normally Open [N/O]
2 COM Linked Live feed (230V AC heating applications only)
3 L Live feed (230V AC)
4 N Neutral

with the diagram showing NO (1) going to SL on the boiler, COM (2) going to L on the boiler. L (3) and N (4) going to mains feed.

Any advice either on what I need to do to fit this particular thermostat (I haven't bought one yet) or a reasonably cheap wireless receiver which will work with the Baxi 80e would be appreciated. Given where the boiler is installed I have no additional mains points - just the isolating switch for the boiler itself.

I realise this makes me sound like a complete noob but I do have enough competence to wire circuits etc. like this once I know the terminology and what's expected - so yes while "call an electrician" is a valid answer, it's not the one I want to hear.

 

[slippyr4]

Power the stat in parallel with the boiler - you could run a cable from the boiler L+N terminals to the L+N supply terminals on the stat (3 and 4 on the salus). Then use another cable to go from 1+2 on the boiler to the COM and NO on the thermostat.

 

[londonbluefish]

So get some 4-core cable to do this wiring.

Heh, typical I found a reply on another thread which also seems to answer the question.

"the transmitter side of the unit mounts next to the boiler via a four core cable. a live and neutral should be taken from the boilers live and neutral were the incoming mains has been wired and that in turn will go to the l & n in the transmitter. the other two cores will go from the boilers room stat terminals that have a link fitted (remove) and inturn go into the correct terminals in the transmitter (this should be in the instructions)."

Shouldn't have searched so specifically for the boiler model.

Thanks for your help anyway.

 

[slippyr4]

5 core cable. You must not use the earth core as a live conductor.

 

[bernardgreen]

"the transmitter side of the unit mounts next to the boiler

Transmitter next to boiler ?

It should be the receiver next to the boiler to receive commands sent from the transmitter in the remote thermostat / controller

 

[londonbluefish]

Sorry I meant the receiver.

I know the colouring of the 4 core I bought was not ideal it looks a bit like 3 core + earth only the wires at all the same size.

You will maybe shoot me but I am sheathing the ends of the 'wrong' colours with colour and label. I believe this is a legitimate practice. After all physically the wires are all the same. There was no alternative for the four core in the store.

 

[slippyr4]

It's ok to put sleeving on any conductor except earth. Do not use that for a live conductor.

If you don't have enough conductors you can use two cables

 

[David937]

I wouldn't recommend the Salus of you're still thinking of buying one. I had one before and it was awful.

 

[AGAS]

 

[londonbluefish]

I wouldn't recommend the Salus of you're still thinking of buying one. I had one before and it was awful.

Oh well it's bought and installed now - any reason you found it to be bad?

Which model? I went for the T105RF in the end, fairly simple and a bit quirky in places but looks like it will do the job - at least to the same degree as an old rotary analogue one if nothing else. Will soon see how good it is - did initially seem to be reporting the room temp rather high (thought it was 21 deg C in October in an unheated lounge but then I had been clutching it trying to work out why a 'moon' is eco and a 'sun' is comfort mode.)

Ah well... it's settling down to reflect the chilliness of the room now I've put it where the old thermostat was.

 

[David937]

It was a RT500rf I think, it was really sensitive and used to result ib large swings in temperature, my parents found it a bit a bit fiddly too. Can't comment on reliability as it was soon changed. This was a while back so they might have improved now.

 

[AGAS]

This was a while back so they might have improved now.

nope !

 

[londonbluefish]

Oh well, never mind, we'll see how it does. I would have tended to go with a Honeywell but this is what was going at the time. Can't be any worse than a disconnected thermostat

 

[durhamplumber]

god forbid you use the green and yellow wire as anything other than earth.The universe will implode!.

 

[slippyr4]

The universe won't implode. But people have been killed when they've assumed that an earth coloured wire is an earth, when some idiot has wired it up as a live conductor.

It's criminally negligent, in contravention of the wiring regulations and thus against the law. If you think it's ok, I'm bloody glad you're not my plumber.