Economy 7 immmersion heater

[Picalillian]

hi, I’ve got a thermal store water heater running on two immersion heaters, one boost and one on eco7 circuit. The eco7 one seems to have started working only intermittently. Occasionally I’ll get up and find that the water is running cool when it should have been heated overnight. Usually it’s heated again the next morning, so it’s not the immersion that’s busted.

I thought that it might be down to a faulty thermostat, so I swapped that out. It’s definitely working because I adjusted the tenperature setting on it during eco 7 hours and could hear it clicking on and off. I thought that swapping the thermostat would solve the problem but yesterday morning the water was running cool again and it felt to the touch like the tank hadn’t heated overnight at all. This morning the tank was hot again, so the immersion is clearly still operating.

Totally at a loss as to what’s causing this because it’s intermittent. Anyone have any ideas before I call someone in?

 

[terryplumb]

Sounds like a switch or timer problem ,maybe loose connection on the circuit.

 

[gasbanni]

It could be a limescale problem on the element had similar problems on this ........try swapping the main of peak element for an incalloy one ....limescale doesn't build up on them.

 

[Diver Fred]

Is your 'Timeswitch' a clock based one or a wireless (or even a 'Smart Meter') one. My father has a wireless one and whilst he gets all the necessary hours or cheap electricity in a day it isn't always overnight anymore. Recently it's been coming on around 09:00 for up to 6 hours and again in the early evening for the balance of the daily allowance.

 

[Picalillian]

I woke up this morning and it hadn’t heated for the second night in a row. Took the panel from the fused switch that powers it (this was still during eco 7 hours) and there was power going to the socket but not away from it. Called an electrician who says it’s most probably the switch or the fuse in there, which seems to make sense.

Odd that it has been failing and then working again intermittently - unless it’s a bad connection in the switch rather than the fuse. Going to change the whole switch tonight and that will hopefully solve the issue.

Thanks for the replies - fingers crossed this works and I don’t have to change the whole immersion out!

 

[vinty]

.

 

[seasickstevie]

How old is it?
Chances are that the elements breaking down.

 

[Picalillian]

I changed the switch then waiting until half 12 when it switches to eco7. Immersion still didn’t come on! So, while the power was there I tested the wires going to and from the thermostat. There was no power coming away from it (to the element) even when I turned it right up - so I assume that thermostat is busted now (only bought it the other day). luckily I still had the old one so I swapped it out, and the heater came on!

Shows that the problem wasn’t originally the thermostat. I’m hoping it was just the switch and that the new thermostat breaking was just a coincidence. Anyway, hot water for one more day.

I didn’t know immersions could ‘break down’ like that. I assumed they were either working or not - can it be the case that if they’re old they’ll work intermittently? It is very old. Hasn’t been changed since the flats were built 20 years ago as far as I know. Certainly not in the 10 years I’ve been here.

 

[JohnD]

The new thermostat will have an overheat cutout (look for a "reset" button).

Could it have tripped?

 

[Picalillian]

I noticed a reset on it, which I’ve pressed in, although I’ve removed it now so I don’t know if it’s working again. Shouldn’t have overheated though, given that the tank was cold? Either way it looks like the thermostat wasn’t the problem, as the original is back on now

 

[crystal ball]

Old thermostats can get a bit unreliable as the contacts can get pitted or even weld closed