Immersion heater not heating?

[UseLeSsDiYr]

Thanks all. It is looking very likely that the element has gone.

endecotp - what will it mean if there is resistence on higher ranges? I think I've already measured all terminals against earth; all returning 1__._

Burnerman - re. first finding, just so I understand, when you say it's 'switched on', do you mean having a probe at each terminal (grey and brown), so off would be just having one probe on either grey/brown and the other probe not touching anything?


Thanks for putting up with me today everyone; at least I'm still alive thsi Sunday evening!

 

[St0rmer66]

11" if it's in the side then, it's the size of the element not the thermostat.

 

[Burnerman]

When the thermostat has switched on, there is electrical continuity between brown and grey. When the thermostat senses that it's temperature has been reached, there is no continuity between brown and grey.
So.....the element has called it a day, so here's some things to consider.
The hot water cylinder is likely to be gravity fed with cold water from a large tank in your loft.
When the immersion element is replaced, the fresh water supply to that tank has to be shut off.
The hot water cylinder has now to be drained, by connecting a hose pipe to the red drain down cock.
With the tank empty, the immersion heater can be unscrewed, ready for replacement. So.....
Can you shut off the supply to the loft tank? Next, the rubber washer in the drain down cock is likely to be perished, and you'll need a replacement. Next, the immersion heater may be as tough as hell to unscrew. If it comes out, then it's off to the plumbers suppliers for an exact replacement. Of course, in the mean time, your house will be without hot water....life's never that easy, is it?
Just some points to ponder - have a good evening.
John

 

[UseLeSsDiYr]

Unscrewing the immersion heater is the part I'm not looking forward to.

The family has had to improvise over past few days with no hot water.

Thanks for perservering with me today John, your help along with others have made things clearer and conclusion has been reached.

Have youself a good evening too.

 

[UseLeSsDiYr]

Hi

My silly question for today is, can I remove the fuse at the mains fusebox to the water heater and have the mains supply on so effectively isolating the heater so work can be done over the next week, without having to power down everything in the rest of the house?

 

[Burnerman]

Yes, of course you can.
John

 

[Agile]

It is very likely that the element has burst open and the element is in contact with the water and a small current is flowing through the water and slightly warming it.

Those galvanised tanks are very old, usually 40-50 years. It would give a good energy saving by replacing it with a modern insulated cylinder!

But at least with that kind of tank there is a smaller risk of damaging the tank while trying to remove the element compared with a thin copper one.

Tony

 

[stem]

You don't have to completely drain the cylinder, as long as the water level is below the immersion heater boss, that will be fine. In fact if you leave most of the water in, the weight of it gives the cylinder some stability and can prevent damage to it and the connected pipes, particularly if the immersion is a tough one to loosen.

After you have turned off the cold supply to the feed and expansion tank, open the hot taps until water stops flowing out of them, then open the drain off and remove a few more gallons.

 

[St0rmer66]

You don't have to completely drain the cylinder, as long as the water level is below the immersion heater boss, that will be fine. In fact if you leave most of the water in, the weight of it gives the cylinder some stability and can prevent damage to it and the connected pipes, particularly if the immersion is a tough one to loosen.

After you have turned off the cold supply to the feed and expansion tank, open the hot taps until water stops flowing out of them, then open the drain off and remove a few more gallons.

View attachment 84051

If it's side entry then it probably goes in right near the bottom! So it does need draining. It's also a steel tank, much stronger in the first place.

 

[Agile]

In fact if you leave most of the water in, the weight of it gives the cylinder some stability and can prevent damage to it and the connected pipes, particularly if the immersion is a tough one to loosen.

I don't think the weight of 150 mm of water is going to be very significant compared with the weight of that galvanised tank!

Also unless very badly rusted, its not so likely to be damaged while removing the element. Can still be very difficult though!

Tony

 

[JimCrow]

In fact if you leave most of the water in, the weight of it gives the cylinder some stability and can prevent damage to it and the connected pipes, particularly if the immersion is a tough one to loosen.

I don't think the weight of 150 mm of water is going to be very significant compared with the weight of that galvanised tank!

Also unless very badly rusted, its not so likely to be damaged while removing the element. Can still be very difficult though!

Tony

you haven't mentioned your 36 inch stillsons yet Tony

 

[UseLeSsDiYr]

Evening everyone - sorry I haven't replied!

Good to know that the tank is less prone to crack when replacing the element.

 

[Burnerman]

Hello again!
Whether the immersion is tight or not is the same as asking 'how long is a piece of string, etc'.
There are appropriate spanners available - both conventional or box - but they can't accept much leverage, unfortunately.
Hence a bloomin' set of Stillsons isn't such a bad idea!
The new immersion should come with a new fibre gasket, and it's a good idea to get some sealant too so you get it done in one move.
As Clint Eastwood may say .......'do ya feel lucky?'
Stay in touch
John

 

[Agile]

you haven't mentioned your 36 inch stillsons yet Tony

I actually have a 48" one too but its a bit heavy for an immersion heater. Used to use it on 2" steel pipework.

But I normally use the 36" one on a box spanner as that's grips better! In fact on a foam covered cyl it would not be possible to get the stillsons on otherwise.

Also have a couple of cast iron ring spanners which can be helped along with a club hammer. But would not do that on a copper cylinder!

 

[UseLeSsDiYr]

As the heating element is from the side, I think I will purchase an 11" titanium element (good and durable for hard water areas?), a box spanner and some PTFE tape.

Do I also need to buy some 'jointing compound' or alternative to paste between the ring seal on the element unit?

When I shut the water supply off to the heater, and turning on all the hot water taps, how much water will be left in the tank before the rest needs to be drained from the drain cock? Will I be able to improvise and use an old washing machine hose on the drain cock and drain into a bucket?