Immersion heater problem

[simon_1975]

Hello

Hope someone out there can help!

Recently my immersion heater is failing to switch on over night. It is on a economy 7 tariff with a 'boost' switch wired into the daytime rate. The boost is working fine (ie, water heats up OK if I manually switch it on), but overnight nothing seems to happen (my cylinder is fitted with a single element). I have checked all fuses (which are all OK), even replaced the thermostat but still no joy. My storage heaters all still work OK (these are also on E7), but the light on the isolation switch in the airing cupboard is failing to light during the E7 hours, so I am lead to believe that the issue is not with the immersion heater but something upstream of this.

Anyone out there had similar experiences?

Thanks in advance.....
Simon

 

[Softus]

Er, yes, lots of similar experiences, but I assume that you want to fix the fault rather have a chat about it

If the off-peak heater neon used to light up, but now doesn't, then either there is no supply to it or it has gone faulty.

Latent wiring faults do happen, albeit rarely, but if your fuses are all intact (or MCBs all switched on) then the prime suspect is the off-peak element. I would compare the resistance of it with that of the peak-time element - something around the 20 Ohm region would be reasonable.

If it's the element then you'll need a plumber. If not, then unless you're competent and confident working with electricity, you'll need an electrician.

 

[simon_1975]

Thanks for the advice. I will certainly get an electrician to look at it as I think the issue stems somewhere from the CU.

I took a look at the ‘boost’ clock yesterday (power off of course and checked with a multimeter to check it was safe). The clock is a manually activated timer which will activate the immersion for up to a hour (depending on how far you turn the dial around).

Both the E7 cable and the standard tariff cable terminate into this boost timer, then a single cable comes from this and routes to the single immersion element upstairs. I have ruled out that there is a problem with the cable from the boost clock to the immersion as it works ok when the boost is manually activated.

Two fuses supply the boost clock. The standard tariff feed is located in the main CU (15A) and the E7 comes from a separate CU with a single 15A fuse. Again, this may be where the problem stems from? (faulty switch on E7 CU etc?). Again, the E7 supply is activated elsewhere around the house on the storage heaters (fed from a separate CU), but for some reason the storage heaters work, but no E7 hot water!

I think I will check the switch on the E7 immersion CU, but failing that it is a job for the pros!

Thanks again for your input…

 

[Softus]

You're welcome - it would be interesting to hear the outcome, when it's all fixed and working.