Immersion heater fault (edited)

[Jean THT]

Hi everyone,

Thank you for a great forum.

I'm trying to find someone to fix my hot water issue and get a recommended plumber. The only visible part of my heating system is the cylinder pictured below.

A Google search indicates that Super Seven cylinders were built by Kingspan, but I've contacted them and they said it's not one of theirs. It seems similar to this product. I don't think there's a separate heating system to the cylinder, I don't see anything else apart from it in the closet it's installed.

If you know what make is this cylinder and where I should start to get it fixed, that would be much appreciated.

 

[stem]

I think you are getting your terms mixed up.

This is a boiler:

This is a hot water cylinder

And this is an immersion heater that fits inside a hot water cylinder

1. If the boiler has failed, you will need a professional to repair it.

2. If your hot water cylinder has failed, it will be leaking

3. If your immersion heater has failed and not heating the hot water in the cylinder, it should be replaced.

Some systems have a boiler that provides the central heating and heats the hot water cylinder. If an immersion heater is fitted is is usually only there as an emergency back up and not normally used.

 

[Jean THT]

Ah, thanks for the explanation. Let me edit the post to be more accurate.

 

[stem]

OK thanks for the edit, we will discount the boiler.

Hot water cylinders are made by many manufacturers, you don't need to replace it with one from the same manufacturer However, is the cylinder leaking? If not you don't need to replace it.

If the cylinder is not leaking and you don't have hot water you just need to replace the immersion heater or repair the faulty fuse / switch/ wiring / timer associated with it, as necessary.

 

[Jean THT]

Thank you.
There is no leak, fortunately. The system stopped heating the water yesterday. I've changed the fuse of the control switch, to no avail. I'll look when I'm back home for the rest of the wiring and the timer.

I just watched that video showing how to replace the immersion heater. I think I'll leave that to a pro

 

[Diver Fred]

It could be that the thermostat has failed - it's an easily (user) replacable item inside the immesion heater - take the cover off with the power off of course.

 

[Jean THT]

It could be that the thermostat has failed - it's an easily (user) replacable item inside the immesion heater - take the cover off with the power off of course.

Ok, thanks. Is there a way to check the thermostat without a multimeter?

 

[stem]

Maybe check the timer setting. Perhaps the water wasn't hot yesterday morning because the clocks moved forward one hour. If you didn't move the timer forward too, it would have come on one hour later than it did the day before. It should have heated up at some point though, unless you left it switched off.

Having said that, the usual idea of the timer is to heat up the hot water during the night using 'off peak' energy as per the label on your cylinder so it wouldn't normally be set to come on just before you need it, unless you are an early riser.

 

[Jean THT]

right, thanks again. So here's my check list for later today

1. replace the fuses and check the wiring
2. check the thermostat
3. check the timer

IIUC, if all checks out, it's likely that the immersion heater needs to be replaced.

 

[Tigercubrider]

my immersion has a tiny button that pops out if it overheats.
With mine, power off, ( I unplugged mine) remove the small nut that holds the cap on, remove cap, the small knob is at the front and a press with the flat of a screwdriver blade pops it down with an audible click.
Cap back
sure cap on,
Power up,

 

[Jean THT]

my immersion has a tiny button that pops out if it overheats.
With mine, power off, ( I unplugged mine) remove the small nut that holds the cap on, remove cap, the small knob is at the front and a press with the flat of a screwdriver blade pops it down with an audible click.
Cap back
sure cap on,
Power up,

I'll try that out if there's a button on the immersion, thanks!

 

[Jean THT]

Right, so I've got two new switches to replace those ones, which had dead neons:

I think that I've found the tiny knob (circled below). It was popped out, I've pushed it back. I'll have to wait until midnight to see if that did the trick.

Here's the other immersion head.

I can't find the timer though. Where should it be?

 

[JohnD]

you have two immersion heaters? that is typical for people on an economy-7 type of electricity tariff, where it is cheap rate overnight.

Your offpeak circuits (usually including storage heaters) may be a controlled by a central timer or radio-controlled switch that is next to, or part of, your electricity metering apparatus.

please photograph your meters and consumer unit(s) and the cables around and between them, and any curious box next to them.

the immersion heater that tripped, was it the one at the bottom of the cylinder, or the one at the top?

What temperatures are the two thermostats set to?

the immersion heater that tripped looks like the cable cores are black and sooty, perhaps from overheating. give them a rub with tissue, see if it comes off. There may be a bad connection overheating. Test the tightness of the terminals (with the power turned off)

 

[Jean THT]

Thanks for the help!

I'm hearing some noise coming from the cylinder and the pipes are getting warmer. Something has restarted! I suspect that there is no timer, despite the boiler being a special economy 7. It is 19:31 at the time of writing this, and it should have started to heat at midnight.

The meters are gathered on the ground floor, I'm on the third floor. I'd need a key from the caretaker to open it, I'd gladly do that if it helps, but do you think a radio-control switch would work across 3 floors? Here's a pic of my fuse box panel. There's a wooden panel above it that contains more cables, and I'd rather avoid opening it unless you think the timer could be in there.

The immersion heater that tripped was the top one.

One thermostat is set to 60, which can be seen in one of the immersion heater photo, and the other one doesn't have temperatures, but rather an arrow pointing at the middle between + and - signs.

Will give a rub to the cables as you suggest.

 

[JohnD]

I see you have two consumer units. Quite likely one is full-price and one is off-peak. In the right hand one I can see a blue shield, which should be for a 15Amp circuit, typical of a storage heater or immersion heater, so is probably for off-peak circuits. Have a look at the labels to check.

The radio-controlled teleswitch, if there is one, picks up a timed switching signal from the BBC Long Wave (Radio 4) transmitter. It is not controlled from your home. That will turn it on and off a certain number of minutes and seconds before or after the contracted period. It usually works inside a home unless it is in a cellar.

i will postulate that your timer is by the meter, and that you have two cables from the meter(s) to your two consumer units, and that the off-peak consumer unit will (should) probably be timed to come on overnight. The upper immersion heater supply will be live 24 hours, subject to your local switch.

But that might not be the case. Sometimes wiring is changed, deliberately or otherwise.



Because hot water rises in the cylinder, the upper overheat trip can activate when its own element is overheating, or if the lower one is overheating.

Is your tapwater scalding in the mornings?