Replacing an old Economy 7 heater with a modern one, will I save much on electric bills?

Dandytf

Swipe said:

You really should have got the switch with a red light then you wouldn't need to ever check the fuse but for info, my 3.4KW box of bricks has a 13amp fused switch.

100% definately and I've bookmarked Dimplex help titled...

QM QMRF storage heater is cold. Not taking a charge. How do I resolve?

Scorching Temps aside, this is the fault I suspect maybe what I'm experiencing, i.e. No Overnight Auto Charging.

thanks
 

Dandytf

mser's efforts aren't wasted, I've pinged Electrician with above required info.
I guess between Original DQ Electrician/Dimplex/+|Pre Used NSH Repairers.

That leaves 'All options on the Table'

thanks appreciated.

Gerry1

Your Toolstation link is a red herring.  That's a switch, not an outlet.

It's the sort of thing you'd use where it may not be immediately obvious that a remote hardwired circuit has been left on accidentally.  It might be fitted above a worktop in the kitchen to control the electric underfloor heating or the boost immersion heater upstairs.  The 45A is just the maximum current it can handle.

BTW, you don't need to include all that clutter in the link, better to keep it simple by deleting the question mark and everything after it.

Gerry1

Swipe said:

You really should have got the switch with a red light then you wouldn't need to ever check the fuse but for info, my 3.4KW box of bricks has a 13amp fused switch.

@Swipe ...which will draw 14.17 amps.🔥

Swipe

Gerry1 said:

Swipe said:

You really should have got the switch with a red light then you wouldn't need to ever check the fuse but for info, my 3.4KW box of bricks has a 13amp fused switch.

@Swipe ...which will draw 14.17 amps.🔥

Well it's been fine for the last decade it's been there so must be pulling less that the specified 3.4KW. If not, surely the fuse would blow before a fire? It was also signed off by an electrician and I have the certificate somewhere.

The model is this:

https://www.credaheating.co.uk/product/tsr24mw-tsr-slimline-mw-storage-heater

mmmmikey

13A is a nominal rating - a 13A fuse will allow a current of 20A to flow indefinitely without blowing. You can find an explanation of why here, or just Google "13A fuse blow current":

https://www.pat-testing-training.net/articles/fuse-operation-characteristics.php

CSI_Yorkshire

mmmmikey said:

13A is a nominal rating - a 13A fuse will allow a current of 20A to flow indefinitely without blowing. You can find an explanation of why here, or just Google "13A fuse blow current":

https://www.pat-testing-training.net/articles/fuse-operation-characteristics.php

Which is why frequently now it is the MCB tripping first and not the plug fuse blowing when there is a fault. 

mmmmikey

....and also why you shouldn't plug multiple high power devices into an extension lead thinking it is safe because the fuse will blow if you overload it. You can still melt the cable, plug or outlet and cause a fire - which sadly still causes fires that take lives.

Gerry1

Seems your electrician didn't do his sums properly !

A fuse won't blow immediately the current rating is slightly exceeded: the rating is the current it can support indefinitely.  The higher the excess current the faster the fuse will blow.

As you've found, a fuse with a slight overload may still keep operating but it will be running too warm and may eventually become brittle and fail.

Your voltage could legally rise to 253V so your heater could then draw 14.93A if originally rated for 240V.

Swipe

Gerry1 said:

Seems your electrician didn't do his sums properly !

A fuse won't blow immediately the current rating is slightly exceeded: the rating is the current it can support indefinitely.  The higher the excess current the faster the fuse will blow.

As you've found, a fuse with a slight overload may still keep operating but it will be running too warm and may eventually become brittle and fail.

I'm pretty sure it was only pulling 3.25KW (inc 0.70KW constant base load) according to the IHD. I'll have to check it again. So at 2.55KW I'm guessing one of the elements has failed then, assuming it has 4 of them.