Hi,
I can't find any reference anywhere to anyone having the same situation as me so I've started a new topic.
I've got a British Gas installed system - BG C1 combi boiler (which I understand from my research is actually a Worcester Bosch SI 28 ) and a BG RS1 thermostat (which I understand is a Drayton RTS1).
I'm trying to replace the thermostat and I was expecting 3 core + E.....but it has 4 core + E.
There is a brown and blue wire which are live and neutral as expected, and then 2 black wires. Both black wires are connected to the same terminal, labelled 'call' - which appears to be equivalent to switch live (?)
Has anyone seen this setup before? Does anyone have any ideas as to why I have 2 wires connected to 'call'?
I've only found 1 semi-related reference through a huge amount of online searching. One site suggested that sometimes plumbers run extra wires at the time of install to provide redundancy - but I only read that in one place, and it seemed to suggest the extra wires were left unconnected unless/until needed.
I've looked through the online manuals and there is no apparent need for the extra wire. The install was originally done by BG, and was only done a few months before I bought the house - so it is unlikely there has been any DIY tampering with it because it was new.
I could just go ahead and rewire both into the new switched live terminal, but I'd prefer to try understand exactly what is going on first lest I make a huge mistake!!
Any thoughts?
Thanks in advance.
John
I can't find any reference anywhere to anyone having the same situation as me so I've started a new topic.
I've got a British Gas installed system - BG C1 combi boiler (which I understand from my research is actually a Worcester Bosch SI 28 ) and a BG RS1 thermostat (which I understand is a Drayton RTS1).
I'm trying to replace the thermostat and I was expecting 3 core + E.....but it has 4 core + E.
There is a brown and blue wire which are live and neutral as expected, and then 2 black wires. Both black wires are connected to the same terminal, labelled 'call' - which appears to be equivalent to switch live (?)
Has anyone seen this setup before? Does anyone have any ideas as to why I have 2 wires connected to 'call'?
I've only found 1 semi-related reference through a huge amount of online searching. One site suggested that sometimes plumbers run extra wires at the time of install to provide redundancy - but I only read that in one place, and it seemed to suggest the extra wires were left unconnected unless/until needed.
I've looked through the online manuals and there is no apparent need for the extra wire. The install was originally done by BG, and was only done a few months before I bought the house - so it is unlikely there has been any DIY tampering with it because it was new.
I could just go ahead and rewire both into the new switched live terminal, but I'd prefer to try understand exactly what is going on first lest I make a huge mistake!!
Any thoughts?
Thanks in advance.
John