immersion heater wont stop boosting

[monkle]

Hello,

I have just had to replace a copper immersion heater that had split near the top, causing the fuse to blow when the heater switched on. I have replaced the immersion heater with a titanium one from plumb centre, which has a thermostat and rdt.

I can now get hot water, but I cannot switch off the boost. I have quite an old Horstmann economy 7 quartz maxistore, it has two dials - one main one for the clock, and a smaller 1 hour dial, which when turned to start switches on the element. For 1 hour, the water is heated, then it used to switch off. However, now it reaches the stop marker, clicks quietly (used to click very loudly) and leaves the boost on.

The element broke whilst I was away, so to see what was happening, I took the cover off the element on the tank, and switched on the boost, which provided me with a bang and a spark, after which the main fuse went.

Have I fried my timer unit? I hope not!

Thanks

Ben

 

[chrishutt]

Ben, I have a vague recollection of having done something similar myself - blowing the circuits of an economy 7 control unit by overloading the immersion heater circuit. I had to replace the control unit!

 

[monkle]

Thanks Chris,
<grumble mode>
As I suspected then, typical!
<grumble mode off>

Ben