fuse blows after installing timeswitch

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Hi,

we've recently had a timeguard NTT03 timeswitch installed to an immersion heater that was always on,
but the fuse (13A) keeps blowing after maybe an hour or so and I'm not sure why,
do this connections look about correct to you?
thanks in advance.
timeswitch.jpg 15775471430488401796345771421623.jpg
 
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thanks for the help Flameport! I'm a bit of a newbie and not sure if this is what you're asking but the label shows:

2 x 3kW @ 240Vac 50HZ
2 x 2.8kW @ 230Vac 50HZ

PXL_20211127_115648955.jpg
 
thanks for the help Flameport! I'm a bit of a newbie and not sure if this is what you're asking but the label shows:

2 x 3kW @ 240Vac 50HZ
2 x 2.8kW @ 230Vac 50HZ

View attachment 252177

You can only power one of the two elements, via a 13amp fuse. The usual arrangement with two elements, is a short element and a longer one. The longer one can heat up the entire cylinder, so is usually on a timer for heating on off-peak E7. The shorter one is normally used during peak when the energy costs more, often on a press to run one hour button, but only heating the upper part of the cylinder.
 
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Thanks Harry,
we don't have a dual meter so we wouldn't be taking advantage of having the 2 elements. which is also the reason why I wanted to have a timer so its not on all the time.

anyway how would I go about fixing this? (again as a total newbie and even if temporarily so I can get some hot water before someone who knows what they're doing comes to fix it properly if needed).
 
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Is this powering one element or both? What was there before?
 
@CBW sorry I don't really know if its powering both or if it was, before there was a switch like this
PXL_20211127_115036001.jpg PXL_20211127_122043615.jpg
 
That timer is probably not designed to supply two elements, from what I can see - if you were to remove one of the two browns from the rightmost terminals and add a connector to make sure it is insulated, it would enable you to get one of the two elements working temporarily. If you can check and make sure it is the brown for the shorter element, even better, but...

If only a small amount of water gets hot at the top, swap the brown you have removed, for the one the one still in that rightmost terminal.

Where is the fuse located, which is blowing?

I think your original setup allowed one element, or the other, but not both at the same time.

Do you actually have an E7 off-peak metered supply?
 
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@ Harry, brilliant thanks so much!!
is there any way to figure out which is which? and just to understand, how come I should have the shorter element connected rather than the longer one in my case?
 
@ Harry, brilliant thanks so much!!
is there any way to figure out which is which? and just to understand, how come I should have the shorter element connected rather than the longer one in my case?

No, you need to have the longer element connected to the time clock, in order for a full cylinder of hot to be produced when the timer switches on.

The shorter element is intended for 'on demand' hot water, or a quick boost during the day, when E7 is at peak rate cost. That, rather than a simple switch, often uses a push button timer so it can only stay on for an hour or so if pressed.
 
no we don't have an off peak meter, the fuse is located in a separate a power switch that feeds the timer:
PXL_20211127_125913963.jpg
 

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