Digital Programmable Timer for Immersion Heater

by **Kismet56** » Wed Jul 22, 2009 3:30 pm

I have bought a Distribution Timer Switch from Conrad and am confused by the instructions. I have contacted them but they are a German company so communication is a problem. They tell me to connect the power to terminals 1 & 2 (not bothered which is Live or Neutral) but on the output side I have a choice - 3 & 5 for an Open Circuit or 3 & 4 for a closed circuit.

My problem is working out which it is because the connection is to an Immersion Heater which doesn't have a switch but it does have a thermostat so, depending on how you look at it, it's both open and closed!

Does anyone have a definitive answer, please?

by **kbrownie** » Wed Jul 22, 2009 7:37 pm

Name and model,
Why does you Immersion not have a swicth to operate it?

by **sparx** » Wed Jul 22, 2009 7:53 pm

Hi, am a bit concerned as looking on conrads web site of very expensive digital timers that you may have the wrong item for controlling an immersion heater.
the supply, which they say polarity doesn't matter, appears to just run the electronics. The other 3 terms. seems to be a change over switch with 3 as common and 5= N/O & 4 N/C.
These are just a volt free switch so would need to break the Live wire to immersion flex with N&E going straight through. eg in on 3, out on 5.
Also the ratings for heating load seem to only be 10A max, not enough for an immersion.
A wiring nightmare as you will need two cables out of immersion fused spur one to heater via switch contacts plus another which requires fusing down to 3A for timer clock feed, don't even think about it!!!!
Buy a purpose made immersion timer, from 'shed' cheaper easy to connect, English instructions
regards Sparx

by **Kismet56** » Thu Jul 23, 2009 10:33 am

Thanks Sparx. No problem with the type of unit - it has an ohmic load of 3680 watts (16A). I just need to know whether to regard it as an Open circuit or a Closed one.
Incidentally, the instructions are in very good English - it's just that they don't tell me what I want to know and the technical helpline is in German!
For kbrownie: because it's hard-wired to an automatic switch - the timer - but it also has, in effect, another switch - the thermostat.