Immersion Timer being bypassed

[Feendish]

Hi all. This may have been answered loads of times before but I couldn't find an answer using the search.

I've installed an electronic immersion timer (Timeguard ETU2000) between the CU and the On-Off/Sink-Bath switch of the immersion in our house. The wiring was straightforward L/N in from supply, L/N out to load and a common earth. The problem I'm having is that no matter what the timer is set to, the immersion stays on (provided the immersion switch is on) i.e. if the timer is set to OFF, but the immersion switch is ON the immersion stays on despite the fact that the timer is before the immersion switch. Also the LED on the timer unit won't light up when it is supposed the immersion is supposed to be on. This is the second unit I've tried. The first unit was a Masterplug mechanical model which also didn't affect the power going to the immersion. Any ideas? Thanks.

 

[johnnyjb]

If you get a multimeter check the voltage on the mains 'in' (brown+ blue) side of the timer,you should get 230 there abouts.Then check the out side with the timer not set it should read 0 v.then turn the timer on and re check the 'out' side of the timer (brown blue) and should get 230 volts if this doesnt work explain your wiring and what cable goes where ect..

 

[Steve]

If you get a multimeter check the voltage on the mains 'in' (brown+ blue) side of the timer,you should get 230 there abouts.Then check the out side with the timer not set it should read 0 v.then turn the timer on and re check the 'out' side of the timer (brown blue) and should get 230 volts if this doesnt work explain your wiring and what cable goes where ect..

Its more likely that he will get 230 volts both sides regardless of switching.

Was there no timer here before? And you've done the wiing to insert a timer in the circuit?

Please explain exactly how the circuit runs, from the consumer unit/fuse box to the heater. Pictures might help us.

 

[Feendish]

No there was no timer there before. I cut the flex joining the CU and the Immersion switch and wired the timer in between.

CU ------> Timer ----> Immersion Switch ----> Immersion

I haven't messed with any of the cables linking the immersion switch to the immersion heater.

Here's a snap of the instructions.

I connected:

Live wire from the CU to SL (supply live)
Neutral wire from CU to left N (supply neutral).
Neutral wire from Immersion switch to right N (load neutral).
Live wire from Immersion switch to right L (load live).
Both earth wires to the Earth symbol.

I don't have a multimeter (I could get a loan of one) but I suspect since the immersion is working regardless of what the timer is set to that the voltage at SL is the same as at the load Live pin.

 

[Steve]

I would have guessed different to you. SL is more likely, IMO, to be SWITCHED LIVE.

Oh look, here's another snapshot of the instructions, Did you not get to page 5?

 

[Feendish]

Sorry my bad. I wrote that last post quickly before I left work. I double checked the wiring at home and it matches your pic Steve.

Live wire from the Immersion switch to SL (switched live)
Neutral wire from Immersion switch to left N (appliance neutral).
Neutral wire from CU to right N (neutral in).
Live wire from CU to right L (live in).
Both earth wires to the Earth symbol.

 

[bernardgreen]

My first thought is that the lead you cut to put the the timer into is NOT the feed to the immersion switch from the consumer unit but is instead a feed taken from feed to the immersion switch to a socket or other outlet else where.

 

[Steve]

Indeed, is there anything else powered from the immersion heater circuit?

Is it definitely on its own circuit?

Have you checked for other cables in and around the immersion and its control switches?

 

[breezer]

since the led doesnt light my money is on supply in supply out reveresed

 

[Steve]

since the led doesnt light my money is on supply in supply out reveresed

Thought we had already established this isn't the case by copying contradicting diagrams.

 

[alex28]

u need a multimeter to establish exactly whats going on.Disconnect everything and test for voltage across supply and appliance cables-either the timer has gone down or the immersion is being supplied from another circuit-in which case you would get a voltage across the "appliance" cables when disconnected from timer (if these are actually connected to the appliance)