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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Electrical Questions >> imersion heater https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1094939250 Message started by Mice on Sep 11^th, 2004, 10:47pm

Title: imersion heater
Post by Mice on Sep 11^th, 2004, 10:47pm

Guys,
In my new house i have an Economy 7 hot water tank which is heated by two 3kw immersion heaters one at the top and one at the bottom. Trawling through other forums I have now discovered that the bottom one is for the economy 7 heating and the top one is for on demand water. I would like to install a timer to switch the bottom heater on during the economy 7 hours as currently it is just controlled from a fused switch which is inconvenient as the cheap rate is in the middle of the night. Will a standard 16A mechanical timer be sufficient (i assume that the max current drawn will be just over 13A for a 3kw heater, unless they draw more to start with?) or will I have to use the ones made specifically for economy 7 which seem to be about 3 times the price, is there a reason for this?
All help appreciated.

Title: Re: imersion heater
Post by Lectrician on Sep 11^th, 2004, 10:51pm

That sounds fine. But, it should have been put on the switched board with your storage rads if you have them?? But, yep, what you suggest is fine, aslong as you set the times for 12 till 1, and 2 till 6, and keep the clock right, you will be fine :-)

Title: Re: imersion heater
Post by Mice on Sep 11^th, 2004, 11:00pm

Finally someone who seems to know what thy are talking about with regards to economy 7, I have two boards in my study but whoever wired the house has not labelled any of the mcb's, so will the supply switch one of the boards on and off automatically?. the top immersion heater has in indicator on the switch so i know that it works during the day, how should i check to see that the economy 7 one only works at night as it will be expensive to leave on constantly if not setup correctly.

Title: Re: imersion heater
Post by plugwash on Sep 12^th, 2004, 1:52am

probablly best to replce the switch with one that has an indicator

as for the fuse boards can you follow the tails and figure out what the wiring before them is doing?

if not then you will have to test

Title: Re: imersion heater
Post by Mice on Sep 12^th, 2004, 5:32am

Good idea about the switch, Many thanks.