Immersion heater timer

[PuffedPastry]

I live in a rented, all electric flat built in around 2006. Hot water is supplied by an immersion tank, an ariston wrc-nsf. I can't see that it has a timer, it seems just to have an on/off switch wired into the mains.

I don't want to leave the immersion heater on all the time, yet it takes 1 1/2 hours to heat up properly which means that to get hot water for a shower in the morning, I need to switch it on before I go to bed and it's therefore on all night. I don't have economy 7 or anything. It's sort of catch 22.

I'm trying to keep my electricity bill down as much as possible and I can't understand why it doesn't have a timer, am I missing something obvious?

Thanks for any insights.

[BWatchWatcher]

Eugh.
We had a special switch installed. You boost the immersion for intervals of 30 minutes and then it turns itself off. Great for kids and saves that moment where you think you let the fecking thing on all day.

[PigletJohn]

is this cylinder white? What are its dimensions?

If you leave the immersion heater switched on all night, does it boil?

Photo would help.

[Villagernumber9]

You can get a timer that can fit into a fuse spur or socket back box.
You would be able to use the timer or, if needed, use the 2 hour booster.
www.geyser.co.uk/timers-electric-towel-rails-radiators-c-97_122_303.html

[specialsubject]

laws of physics determine how long heating up will take.

ask the landlord how it is all wired and if you can have a timer.

[PuffedPastry]

Thanks for all your replies.

Yes it is white, please see pic, and measures 42 high with a diameter of 20 1/2 ins (107 cms x 52 cms diameter). If by 'boil' you mean, does it make a bubbling sound a bit like a kettle coming up to the boil (had this in a previous much older property with different kind of immersion heater), no, it doesn't. I can hear it's working when I switch it on, but nothing untoward.

Neither the landlord nor the letting agent know how it works Special , I've asked, so I was hoping gather some more information before I approach them again.

[PuffedPastry]

That should read 42 ins high and a diameter of 20 1/2 ins.

[PigletJohn]

Inside that white casing is an unvented (high pressure) hot water cylinder, and some insulation. The white casing is probably no hotter than your hand. There is an electric immersion heater near the bottom, which has a thermostat, probably set at about 60C.

The small upper cylinder is a pressure vessel, containing air, which occasionally needs to be pumped up during servicing.

It contains round about 120 litres of water, which is enough for a bath or a couple of showers.

It works in much the same way as other unvented cylinders, such as the Megaflow, although yours is heated electrically, not by a boiler.

The immersion heater is 3kW and takes about one minute to heat each litre of water (slower in winter, quicker in summer). So about 2 hours from fully cold. Usually less as it will not be fully cold. It costs about 30p to 45p an hour (depending on your tariff) while it is heating, nothing once the water is up to temperature and the thermostat turns it off.

Because the thermostat turns the heater off once the water reaches temperature, you will not gain much by adding a timer. If you find the silver pipe near the top of the cylinder is hot, you can lag it with Climaflex or similar. In winter the slight escape of heat will contribute to warming your home. It is probably so little that the airing cupboard will hardly be warm enough to air clothes.

The cylinder ought to be inspected, and serviced if necessary, annually. It has various safety devices to prevent overheating or overpressure. If you see or hear water being released into the white drain it has a fault.

[PigletJohn]

this guide may not be quite right for your model, but it will be a useful guide. If you email the makers with your model number they may have the correct document.

peteranthony.co.uk/docs/dropbox-boilers/root/530_unvented%20cylinder%20manual%202011_v2.pdf?sfvrsn=0

[specialsubject]

the LL doesn't know how it works? What a twerp. Tenants should be given copies of manuals and a brief guide to the property.

meantime hopefully the estimable PJ has solved your problem.

[PuffedPastry]

Thank you so much PigletJohn, I really do appreciate you taking the time to explain all that to me so clearly. I didn’t realise that the thermostat turned the immersion heater off automatically once it had reached the right temperature. The link to the manual you provided is also instructive, I will try and find the specific one for the model I have. The information on costs too is really helpful as I’ve been concerned that leaving the immersion heater switched on for long periods of time would be expensive but if I’ve understood correctly, once the tank is heated up fully it should then just be ‘topping up’ automatically at intervals to keep the water at the right temperature. No need therefore for a timer switch and it's more cost effective than letting it cool right down and then reheating the whole thing up again.

I will also speak to the letting agent about getting it serviced regularly though to be honest, I’m not sure how far I’ll get with that. The LL doesn't know how it works? What a twerp Um, sadly yes special. The letting agent isn’t always very helpful either. Despite it being a relatively new property, there have been lots of niggles with the heating, wiring etc. and not having rented before, I’m learning the hard way about the kind of questions I should have asked and the things I should have looked out for before signing the tenancy agreement. But all that’s an entirely different thread!

Thanks everyone for your comments and especially of course to PigletJohn for your help, I’m most grateful