Can disconnected old boiler programmer result in not working switch next to it

[tmasa]

Decided to fix an outdoor light which didn't work for years. Tested light wires - no power, tested fuse in the switch - OK, opened up switch - found neutral wire broke off at the connection point but no power anywhere before or after fixing it. Everything is ON on switchboard.

The switch is in really awkward place next to the boiler, and I am not sure on what circuit it sits. There is an old bolier's programmer next to it (depowered), I am just thinking at some point when the boiler was replaced or smart thermostat installed the engineer might have disconnected the programmer in some way that made that switch offline, is it possible ? Everything around that area is working - boiler switch, sockets, old thermostat in the hall.

If that could be the case, how do I check and fix it? I haven't had a chance to see what is behind the programmer unit, would like to understand my options first.

Also, if I decide to remove it completely, is it possible to fit a socket on its place?

 

[Jurassicspark]

I doubt the switch is supplied from the programmer. Instead, it's probably supplied from a nearby socket or a switch.

Also, how do you know if that FCU controls the outdoor light?

Removing the programmer and fitting a socket isn't ideal as it probably won't have power and it will be limited to 3A.

 

[ericmark]

My old central heating programmer supply, is now 12 volts, and it feeds the Nest Gen 3 thermostat, only way to find out is to test.

 

[CountryFan]

Given the location of the switch and proximity of the programmer I would say it’s likely for the heating system. As per @ericmark, would be easier to test. What do you mean by re-powered - it didn’t have power and now it does?

 

[Harry Bloomfield]

Tested light wires - no power, tested fuse in the switch - OK, opened up switch - found neutral wire broke off at the connection point but no power anywhere before or after fixing it.

How have you tested it, what instrument have you used?

 

[tmasa]

I doubt the switch is supplied from the programmer. Instead, it's probably supplied from a nearby socket or a switch.

Also, how do you know if that FCU controls the outdoor light?

It is my best guess, the external cable that powers the light goes out on the opposite side of the wall on the same level/ position and there seems to be nothing else this switch could be for.

There are no sockets nearby, only the boiler on/off switch next to the programmer on the right (that white cable goes from it to boiler)

 

[tmasa]

Given the location of the switch and proximity of the programmer I would say it’s likely for the heating system. As per @ericmark, would be easier to test. What do you mean by re-powered - it didn’t have power and now it does?

Do you it reckon it might be for water heater from the old gravity fed system, I thought that switch was upstairs next to the now removed hot water tank, but yes water heater switch is off on the switchboard.

*depowered

 

[tmasa]

How have you tested it, what instrument have you used?

Just a regular multimeter, I fixed and tested other things today, so assume it works fine.

 

[Harry Bloomfield]

Do you it reckon it might be for water heater from the old gravity fed system, I thought that switch was upstairs next to the now removed hot water tank, but yes water heater switch is off on the switchboard.

I would suggest that is the much more likely scenario.

You could try turning that water heater MCB on, then see if it becomes live at the switch with your meter.

 

[tmasa]

I would suggest that is the much more likely scenario.

You could try turning that water heater MCB on, then see if it becomes live at the switch with your meter.

I suppose I can try it. Is it safe to do so, I am not sure how exactly they terminated that connection upstairs when removing the tank, it is all boarded there now?

If that's the case I am out of options where the outdoor light switch could be, all other outdoor connections have dedicated switches.

 

[Harry Bloomfield]

I suppose I can try it. Is it safe to do so, I am not sure how exactly they terminated that connection upstairs when removing the tank, it is all boarded there now?

It should have been made safe, at the upper end, but if you remove the fuse from the switch, and turn it off too....

If in any doubt at all, get a pro in.