Immersion heater trouble

[Martin Jerome]

Hi, I would be grateful for any advice.

My hot water system at home consists of peak and off peak immersion heaters. I replaced the 'peak' immersion heater around a year ago as the old one had blown. We leave the 'peak' switch on 24 hours a day. It has been fine up until a few days ago when I noticed a 'fishy' smell coming from the cupboard where the hot water cylinder is. Then had a shower yesterday morning and noticed that the water was luke warm. Took the switch off the wall and noticed that the switch was a bit stuck and the black & blue wires had burnt a bit and the insulation was melted. I stripped back all the wires and rewired the switch, now it seems nothing is working at all- not even the off-peak (off peak may have been faulty before as we don't really use it). What could be causing this? Could the switch be damaged and therefore not working?

 

[bernardgreen]

the switch was a bit stuck and the black & blue wires had burnt a bit and the insulation was melted. I stripped back all the wires and rewired the switch

That is a clear indication that the switch has over heated. Either one of the terminals became loose ( they do over time ) or the switch contacts were failing. If the wire had become hot enough to burn then the switch was hot wnough to have been damaged, ""the switch was a bit stuck"" confirms the switch mechanism is damaged.

That will explain why the "peak" immersion is not working. It should not affect the "off peak" so your assumption the "off peak" was already faulty is vaild

 

[Martin Jerome]

Thankyou very much for your response. I'll replace the switch to see if that helps.

 

[Echo the husky]

Why do you not use the off peak element? It must be costing you a fortune using the peak (boost) element all the time.

 

[Martin Jerome]

Replaced the switch & all working now.

Echo- we keep both peak & off peak on 24 hrs a day. Got a big family and we find that if we use only off peak, by midafternoon, there's no water left. Leaving both on all the time means we dont have to think about it too much. No gas in the house & electric bill comes to around £70 a month, so not too bad.

 

[EFLImpudence]

Then, unless you use a lot of the water after 9 or 10pm-ish, the water will be up to temperature by the time the off-peak switches on and so you will not use any of the cheaper rate electricity.

I presume you still have storage heaters so perhaps the loss (or not saving) will not be too drastic.

 

[Martin Jerome]

I'm sure there is a better way of doing it. I don't like the idea of wasting energy unnecessarily. Generally, most of the hot water gets used from 4-8pm. Yes we have storage heaters.

 

[EFLImpudence]

Assuming the immersion takes two hours to heat the water to temperature, then it will indeed be hot when the off-peak comes on at 11 - 12 midnight.

So two hours, 8 to 10pm at 3kW = 6 kWh x 14p? (substitute the difference between your two rates) = 84p per day 'wasted'.

Fiver-ish per week.

If you had a timer, you could set day rate to be ON just between, say, 3pm and 7pm.

 

[Echo the husky]

An immersion heater timer on the peak immersion, carefully set could stop it heating a little before the last hot water is needed each day. This would allow the cylinder to recharge on the off peak supply, and only be topped up on the peak supply. Most electronic timers have a boost button which will allow an extra hour of heating if guests are over and showering in the evening etc.

 

[Martin Jerome]

Could an enthusiastic amateur like myself wire one in?

 

[Adam_151]

If you ware able to change the immersion heater switch, then I do not see why not, as you can get ones which just go in as a drop in replacement for the switch http://www.cnmonline.co.uk/7-day-im...eswitch.html?gclid=CK27y9Dhs80CFVG6GwodiyQD0Q

 

[stem]

I don't like the idea of wasting energy unnecessarily.

By using the 'off peak' rate you probably won't use any less energy, it's just that the 'off peak' rate is cheaper.