Boiler isolator switch wiring problem

Postby DIYdunce » Sun May 27, 2007 11:19 am

I disconnected the isolator switch for our Potterton Suprima 40 boiler in order to fit some hardboard behind it to neaten up a messy installation. Even though I thought I'd noted the wiring & replaced it correctly the boiler is now dead.

The switch has 3 connections on the top and 3 on the bottom. The top 3 seem to come from the house electrics (house built in 2002) and the bottom 3 go to the boiler. The house electrics have 2 reds, 1 yellow, 1 blue, 1 black & 1 earth. The boiler side has 1 black, 1 black+red tag, 1 brown, 1 blue & 1 earth. I think they were wired together in the switch like this...

Terminal 1 2 3
House side: Red Yellow Red
Boiler side Black Brown Black

The house black and the boiler blue are connected directly together with a "chocolate block" type connection. The house blue was just loose inside the switch box, with no exposed conductor showing. The earths from both sides are connected to a pin on the switch box cover.

I've checked the 3A fuse inside the boiler and it seems OK. I'm wondering if the house blue that was loose inside the switch box should be connected somewhere and maybe came adrift when I opened the switch front? But I'm no electrician and don't want to "suck it & see!!" All help gratefully accepted - thanks in advance.


ps - we've hot water from our immersion heater but no boiler and thus no central heating.
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Joined: Sun May 27, 2007 10:51 am


Simply Build It

Postby htg engineer » Sun May 27, 2007 12:31 pm

sounds like a neutral problem, put the neutrals (blue) into the same connector block, should solve the problem
htg engineer
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Joined: Tue May 22, 2007 5:22 pm

Postby DIYdunce » Mon May 28, 2007 11:00 am

Thanx for the reply - I tried that but unfortunately it still doesn't work. Any further thoughts gratefully accepted
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Joined: Sun May 27, 2007 10:51 am

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