Immersion Tank Timer and Thermostat Advice

[bmouthboyo]

So it seems I have an immersion tank with only a on / off switch in the new bungalow my wife and I have moved into. We only use hot water in the kitchen and bathroom taps in the evening, no bath or hot water fed shower.

It is a pain remembering to turn it off via the switch and a few times we left it on for a day. It does not appear to have a thermostat fitted to the side so the water is very hot when on for a prolonged time. I am assuming it has an internal on / off thermostat to stop it getting too hot but cannot see anywhere this can be adjusted. Is there a way to check it has this feature?

Do I need to replace the switch with a timer like a Timeguard FST77 which feeds into a tank mounted thermostat like the Danfoss ATC Cylinder Stat that then feeds to the immersion supply?

 

[stem]

There will be a thermostat, otherwise the cylinder would be physically boiling after about 20-30 minutes. It will be under the immersion heater cap.

Cylinder thermostats used with central heating systems are not suitable for switching immersion heaters as they are not able to cope with the 13A drawn by an immersion heaters, and would burn out.

Proprietary timers specifically for immersion heaters are available, most are designed to work in conjunction with an 'off peak' tariff so as to heat the water during the night when energy is cheaper. They vary slightly from model to model but will come with installation instructions.

If you are not on an 'off peak' tariff and if your cylinder is well insulated, then once it is heated, the thermostat turns the heater 'off' and the water will stay hot for many hours if not used. So there's not a lot of point having a timer. The immersion heater will only come back on when the water cools because you have used it.

 

[SFK]

Bmouth,
If not needing a timer, as a simple solution how about swapping the current switch for one of these Boost Switches that have a countdown timer?
That way you can never have it on for more than 2hours or 4 hours depending on the model.

https://www.google.com/search?q=Timeguard+boost&ie=utf-8&oe=utf-8&client=firefox-b-ab

SFK

 

[JohnD]

It looks like you have a (very old) cylinder with no factory insulation.
Some cylinders are rather small and will hardly do a bath.

You will get a slight gain from putting two red jackets on it, rather than one, and it is definitely worth insulating the pipes, especially the one that comes out of the top of the cylinder. It's easy to do, you can cut the lagging with a breadknife.
https://www.wickes.co.uk/search?text=lagging
Use the thicker grade if you can. Your pipes are probably 22mm (15mm is the common small size, and 28mm is sometimes found)

If and when you cylinder leaks or otherwise needs replacement, your new one will have factory-applied insulating foam, and you could have an upper and a lower immersion heater element so you can use the top one if you only need small amounts of hot water that day.

It might be overheating if the immersion is very old and the thermostat has failed. The thermostat is easily replaced, the element needs a plumber and may be seized in place.
If the thermostat has failed, this can be VERY DANGEROUS and there have been fatalities, so do not delay in changing it.
Newer immersion heaters have a safety overheat-cutout to supplement the thermostat.

The timer is only worthwhile if you can get cheap-rate electricity. A well-insulated cylinder stays hot for easily 24 hours if you don't use it.

 

[Hot&Cold]

Thats a very old cylinder in the previous photos showed a saucepan under the cylinder,is it leaking or any evidence of previously leaking.

Tbh a new cylinder will keep more of the contents hot,rather than keeping the airing cupboard warm your existing cylinder and immersion could be riddled with scale.

 

[bmouthboyo]

The current one isn’t leaking it’s just a pan underneath. It doesn’t appear to have a thermostat built in however!

I think it has been regularly serviced as well as the warm air as it was lived in by an elderly lady who would pay to have it all checked.

 

[Hot&Cold]

Thats an antique.visually looks in good nick but a new immersion heater complete with thermostat is the next step

 

[copea]

The cover reads 'with thermostat'.
The device with the two terminals in the foreground, by the looks of it.

That being said, most likely better to replace the whole thing given its age.

The timer you've linked to is fine.
Much better than the manually switched option you have now.

The cylinder stat you mention isn't what you need. That only switches a small amount of current to activate a boiler, and would melt if you tried to run 13A through it.

 

[bmouthboyo]

Interesting, not sure what the best bet going forward is.

The warm air system is pretty good and meets our needs so will be staying. Hot water we would like to update however.

We are playing with the idea of a gas boiler being installed where the immersion is, then if my thinking is right we need a hot water tank in the attic that can be used by a power shower we would like to install. Am I right in thinking a powerful shower couldn't simply run off a boiler?

I guess there is no way to squeeze a boiler in there and use the existing immersion as the hot water tank to feed a power shower and taps?

Sorry if I am way off the mark, I am a keen DIY car mechanic but a first time buyer with a home. Prefer to give things a go myself but like to ask a lot of questions

 

[rochdalegas]

Is the warm air new or at a similar age to the cylinder?

 

[HERTS P&D]

That immersion needs changing ASAP, it is an accident waiting to happen.

Andy

 

[bmouthboyo]

That immersion needs changing ASAP, it is an accident waiting to happen.

Andy

Looking back through the paperwork that was left with the house it seams the old lady who lived here for 30 years had the warm air heater serviced every year but I cannot see any specific service receipts for the boiler but I assume she had it checked periodically.

Either way I think you are right and it does need to be replaced.

I think I will start a new thread related to my current setup and see what recommendations people give. Thanks

 

[stem]

There is nothing on an immersion heater that requires regular servicing. It's just a heating element and a thermostat. When they fail they are replaced.

An immersion is basically just a big version of an electric kettle and like kettles, don't require any routine servicing. As with all electrical appliances, checks could be done to make sure that it's electrically safe, but there aren't any parts that can be serviced to extend their life.