Altech thermostat to Nest

[CBW]

Edited post #14 to include photo

 

[Billwarbero]

Thanks.
I've rewired the JB, still no joy.
I'm gonna have to check for a fuse inside the boiler, but I am going to get a gas engineer for that.

 

[CBW]

Thanks.
I've rewired the JB, still no joy.
I'm gonna have to check for a fuse inside the boiler, but I am going to get a gas engineer for that.

This is why I suggested looking for a fused switch unit, so you could check/replace this before calling a gas engineer. Do you have access to any test equipment? Multi meter or two pole voltage tester?

 

[Billwarbero]

Afraid not. There are no fused switches that I can see / am aware of. I can only think of the ones inside the boiler.
No testing equipment am afraid.

 

[CBW]

Afraid not. There are no fused switches that I can see / am aware of. I can only think of the ones inside the boiler.
No testing equipment am afraid.

Might be worth purchasing one? You could then test the feeds to make sure there is voltage. Probably cheaper than a gas engineer, which it might not be an internal fuse in the boiler.

 

[Billwarbero]

Yea will look into it, although I am fast approaching the end of my comfort zone.
All I did was: isolate mains> remove NO/COM from old stat> remove L/N from J box to old stat> rewire NO/COM to new stat> switch mains back on and the boiler is gone. So I'm a bit puzzled. Never touched the L/N/E that went from the JB to the boiler.
Thanks for your help so far.

 

[ianmcd]

Double check that you havent pushed one of the wires in the JB too far in and it is connected to the insulation on the wire and not the bared copper

 

[stem]

1. What happens with the Nest connected when you press the manual button in the centre? Does the boiler come on then?

2. When the wires were connected to the Altech, were there just the 4 wires one each connected to L, N, COM & NO? Was there a link between any of the terminals?

 

[Billwarbero]

Double check that you havent pushed one of the wires in the JB too far in and it is connected to the insulation on the wire and not the bared copper

Yeah I've rewired the JB 3 or 4 times, but each time nothing happens.

 

[Billwarbero]

1. What happens with the Nest connected when you press the manual button in the centre? Does the boiler come on then?

2. When the wires were connected to the Altech, were there just the 4 wires one each connected to L, N, COM & NO? Was there a link between any of the terminals?

1. - no, the light comes on in the Nest but nothing happens with the boiler. The I/O light on the boiler is not coming on at all.
2. yea that's correct. L/N from the junction box, and COM/NO to the boiler.

I've rewired the Altech receiver back the way it was, with the L/N from the JB and wired the COM and NO to the boiler, but now even the Altech box doesn't turn on. It's like there is no power coming from the junction box at all.

 

[Billwarbero]

With the old Altech receiver, even if you switched it off or unplugged, the boiler would still work for hot water etc. Now the boiler is just not getting any power at all.

 

[ianmcd]

You have tripped a fuse or breaker somewhere, it is not a fuse inside the boiler, you will have to trace the flex from the JB and see where it goes

 

[Billwarbero]

You have tripped a fuse or breaker somewhere, it is not a fuse inside the boiler, you will have to trace the flex from the JB and see where it goes

Thanks

it was indeed a fuse, unfortunately the spur box was behind a panel wall which I didn't even know could be removed.
Boiler now working and Nest installed successfully.

Thanks everyone for your help / input