Immersion tank issues....

eleanordunhill

Hi all,

We have an immersion tank in our house for hot water only. No central heating is connected to it.

Turned in on about an hour ago and whilst the water is getting warm it's in no way hot. Before it took about 15 minutes to get very hot. Electricity supply is fine, light is on on the switch etc.

Is this likely to be a faulty element which needs replacing? Or could it be something else?

Thanks!

eleanordunhill

Update....

Heater is now up to temperature but it took about an hour and a quarter any ideas? This is not normal for our cylinder which has always taken about 20 minutes max. Any ideas?

Thanks!

Alex1983

You could try the thermostat 1st, there cheap and very easy to swap. If it doesn’t fix it you probably need to change the whole thing, if it’s sat at the top of the cylinder you will need to drain a little water and then hope it comes out with a immersion spanner if it’s low level you’ll need to drain the whole cylinder.

eleanordunhill

Thanks for your reply. So if element doesn't fix it the whole tank may need replacing?

Alex1983

No, you can change the thermostat or you can change the complete immersion heater, not cylinder. If you can’t get the immersion heater out of the cylinder then you would have to change the cylinder.

eleanordunhill

Alex1983 wrote: »

No, you can change the thermostat or you can change the complete immersion heater, not cylinder. If you can’t get the immersion heater out of the cylinder then you would have to change the cylinder.

Thank you!

Ectophile

How cold was the water this time before you turned the heater on?

To heat a tank full of water from cold to hot in 15 minutes would require a seriously powerful heater. This site https://www.electricireland.ie/residential/help/efficiency/energy-efficient-water-heating suggests about 2.5 hours to heat a large tank from cold, and 50 minutes for a smaller one.

konark

Mine always takes at least 45 mins from cold to hot, it's quite small and 2,8kW.

Can't see it being the thermostat.

If it's the element they're a complete b1tch to remove.

15 mins sounds very quick.100 litres of water would take about 20 million joules to raise 45C. To do that in 900 seconds would take over 20kW of electricity!

coffeehound

If the water is getting warm at all, then the element hasn't failed. They normally either fail 'open-circuit' so you get no heat at all, or they fail with a short-circuit to earth and trip the circuit breaker or blow the fuse.

Per earlier post, the thermostat would be the first thing to change – cheap to buy and easy to change.

diamond_dave

I agree with previous post that removing the element is a B***h! You have to obtain a large/special spanner and then you run the risk of damaging the collar on the tank itself if it's been there a while. As others have said the element is working and you can checking thermostat by turning it down(small screw under cover) and hearing a click. Same as any thermostat.

eleanordunhill

Thanks all for your replies! Will get a thermostat at the weekend and give it a go!