Question Re. Connecting New Room Stat To Mains?

[plumbandplumber]

My combi doesn't have a room stat, so I am going to install a wireless one. When I install the stat's receiver next to boiler, what is good practice/OK when connecting receiver to 240V mains? -

A) Connect to the electrical block inside boiler's electrics where boiler's 240V mains supply is connected

B) Connect into boiler's fused spur

c) Either of the above

D) None of the above

Sounds like an exam question. :wink5: Thanks to all!

 

[Jimbob]

I usually do 'A' with 4 core to keep it neat

 

[jefaz]

I go from spur to receiver then switch wires to boiler

 

[Howsie]

C depending on the cable run. IMO when you isolate the heating all the heating components should be isolated as well.

 

[Reg Man]

Don't you wire it from the boiler terminals. Check the boiler manufacturer wiring instructions diagram for which terminals to use? Because that's your interlock between the stat and boiler.

 

[plumbandplumber]

Thanks to all for your help. Seems evenly split between boiler's connection and the spur. Though I don't fully understand Reg's advice. Think he may be referring to the receiver's switching wires, not the receiver's mains supply wires.

Will do what seems easier when I get the tools out at the weekend.

 

[dancinplumba]

The spur will have only one flex outlet

 

[lame plumber]

boilers tend to have a few flex outlets available, best to use them

 

[dancinplumba]

Not many IMO , you may have to use a wiring centre and wiring should comply with 17th and mi's

 

[Reg Man]

Thought most combis have a stat terminal. Its system boilers control wiring that don't always have this facility.

 

[dancinplumba]

Not for power supply to stat but for the switching terminals yes

 

[eaton]

What boiler and model, might be easier to get plug in from manufacturer

 

[stevetheplumber]

the answer is either of the above will depend on layout and boiler model you cant use one flex on the honeywell ones as they have two seperate routes in to seperate what could be high and low voltage cables
never run 240 and low voltage in the same flex induced current can fry a pcb and theres always the chance of someone thinking its all low voltage

 

[plumbandplumber]

What boiler and model, might be easier to get plug in from manufacturer

Baxi 80e

 

[Reg Man]

Terminals on the boiler: Terminal 1 = 230V phase for room stat, Terminal 2 = 230V switched Phase(Live) to time clock then through to stat. Can work the rest out depending on which remote stat package your using.

 

[plumbandplumber]

Terminals on the boiler: Terminal 1 = 230V phase for room stat, Terminal 2 = 230V switched Phase(Live) to time clock then through to stat. Can work the rest out depending on which remote stat package your using.

Thanks Reg.

So, the switching terminals in the 80e are mains, not low volt?

I ask this as I was thinking of using some 4 core flex to the stat's receiver - 2 cores for L and N to run the receiver and 2 cores for the switching. However someone said that running the mains supply for receiver and the swiching wires together in same cable may fry the boiler's boards due to induced current in the shared cable.

If the switching is mains voltage, presumably I can run everything in a 4 core cable?

P.S. There isn't a clock fitted to boiler.

 

[heliotrope]

Terminals on the boiler: Terminal 1 = 230V phase for room stat, Terminal 2 = 230V switched Phase(Live) to time clock then through to stat. Can work the rest out depending on which remote stat package your using.

Bit confusing that answere.

There is no output from terminal 2. Terminal 1 is 230v output for room stat back to 2 to fire boiler.

An external time clock and room stat can be connected accross these to fire boiler.

The reciver would be connected to these with or without a programmer.

Permanant live could be taken from the same block L & N permanant.

 

[plumbandplumber]

Bit confusing that answere.

There is no output from terminal 2. Terminal 1 is 230v output for room stat back to 2 to fire boiler.

An external time clock and room stat can be connected accross these to fire boiler.

The reciver would be connected to these with or without a programmer.

Permanant live could be taken from the same block L & N permanant.

OK thanks. So switching is 230V

So I will run a 4 core cable from receiver into boiler's electrical section to pick up L and N to run the receiver and also provide switching.

No worries about frying anything.

 

[Howsie]

Competent?