Immersion losing heat

Sleeper12

Another option is that the electrictrican wired in both elements instead of one. Very dangerous thing because you could have 6 or 7kw on 2.5 twin and earth. If it is wired like this then one element may have blown & it'll take twice as long to heat the water

BaZmO*

Brego888 wrote: »

But it's never been a problem over the last 4 years up until the last couple of weeks so why would being wired the wrong way round cause it?

Sounds strange alright, but if you were using the heating at the same time that’d contribute to heating the full cylinder.

Brego888

Will try the reset option tomorrow and report back

John.G

Brego888 wrote: »

Will try the reset option tomorrow and report back

You might also see what capacity cylinder you have, it should have a label on it, if its accessible.
Because you are still getting "1/2" heating, then I'd say again, logically, both elements are wired in parallel , the elements. I think are normally 3KW (bath) & 2KW (sink) although my 41 year old Santon is 3.5/2.5 KW, if we assume 5 KW then 75 litres will heat up (from 10C) to 39C and 95 litres will heat to 33C. (in 30 minutes), if the sink element is "blown" then 75/95 litres will heat to 27C/24C. If the bath element is blown then 40 litres will heat to 32C (I assumed 3KW sink element in my original calc). I think the advice would be get it repaired, select "bath" and set the timer to 1 hour.

You can still do this (set the timer to 1 hour) and see what the performance is then, while you are waiting to check it out.

John.G

Sleeper12 wrote: »

Another option is that the electrictrican wired in both elements instead of one. Very dangerous thing because you could have 6 or 7kw on 2.5 twin and earth. If it is wired like this then one element may have blown & it'll take twice as long to heat the water

and hope that he hasn't bypassed the thermostat!

Brego888

OK so I took the cap off and pressed the reset button. There was no click or any feedback from the button though. Not sure it did much.
I've attached a few more photos from below the cap. Do people thing I should move the blue dial from 60 to 70?
I also attached photos of my immersion timer so you know what I'm talking about.

Heating the water now for the usual half an hour to see how I get on.

http://imgur.com/gAKFkvs
http://imgur.com/hA7jCcL
http://imgur.com/ynIQejW
http://imgur.com/qs32tjU

Does the 2/2.85kw on the cap mean that there are 2 heating elements in the tank of the same size?

Sleeper12

Brego888 wrote:

OK so I took the cap off and pressed the reset button. There was no click or any feedback from the button though. Not sure it did much. I've attached a few more photos from below the cap. Do people thing I should move the blue dial from 60 to 70? I also attached photos of my immersion timer so you know what I'm talking about.

That's a good quality timer but it's not installed correctly. Power should first go to the timer. From the timer to the bath / sink switch & then on to the element itself. This way you have the option of using the bath / sink switch.

It's a dual element. 2.85kw each element.

I'm not really convinced that you would get a 10 minutes hot shower from a 30 minutes 2.85kw boost.

Do you have a pump for the shower or is it just gravity on its own?

Brego888

Sleeper12 wrote: »

That's a good quality timer but it's not installed correctly. Power should first go to the timer. From the timer to the bath / sink switch & then on to the element itself. This way you have the option of using the bath / sink switch.

It's a dual element. 2.85kw each element.

I'm not really convinced that you would get a 10 minutes hot shower from a 30 minutes 2.85kw boost.

Do you have a pump for the shower or is it just gravity on its own?

I suppose for the sake of my thread you'll have to take my word for it as myself or my girlfriend have been having 10 minute showers off a 30 minute boost without issue for 4 years!

No just gravity and no pump.

I changed the dial to 70 and did the usual 30 minute boost but no change in hot water amount with my shower just now.

If it comes to it we can always start putting the timer on for an hour but that still doesn't explain this issue.

Sleeper12

Brego888 wrote: »

I suppose for the sake of my thread you'll have to take my word for it as myself or my girlfriend have been having 10 minute showers off a 30 minute boost without issue for 4 years!

No just gravity and no pump.

I changed the dial to 70 and did the usual 30 minute boost but no change in hot water amount with my shower just now.

If it comes to it we can always start putting the timer on for an hour but that still doesn't explain this issue.

I wasnt doubting your honesty, I was thinking both elements might be wired together at the timer giving over 5.5KW but if is only gravity then 2.85kw is enough to give you a 10 minute shower

Brego888

No worries I appreciate the replies.
Any other theories on what is going on here?

browner85

Have u a back boiler in the house ? Pump could be switched on and could be cooling the water in the cylinder

Brego888

No back boiler.
It's a ground floor apartment.

Wearb

browner85 wrote: »

Have u a back boiler in the house ? Pump could be switched on and could be cooling the water in the cylinder

Any of your main heating pipes near the heating boiler getting warm at the end of your 30 min boost?

Brego888

Wearb wrote: »

Any of your main heating pipes near the heating boiler getting warm at the end of your 30 min boost?

No all pipes cold around the gas boiler.

Only pipe that is warm around the water tank is the one coming out of the top in the below photo. Should the middle or bottom pipe be warm too?

http://imgur.com/57CiPj4

John.G

Brego888 wrote: »

No all pipes cold around the gas boiler.

Only pipe that is warm around the water tank is the one coming out of the top in the below photo. Should the middle or bottom pipe be warm too?

http://imgur.com/57CiPj4

Is it warm/hot at the Myson TRV (white valve), if so or even if not just turn the white knob clockwise to its stop,this will prevent any chance of losing heat through the coil and boiler system, put it back to its original setting (5?) when you flash up your boiler again.

John.G

Sleeper12 wrote: »

That's a good quality timer but it's not installed correctly. Power should first go to the timer. From the timer to the bath / sink switch & then on to the element itself. This way you have the option of using the bath / sink switch.

It's a dual element. 2.85kw each element.

I'm not really convinced that you would get a 10 minutes hot shower from a 30 minutes 2.85kw boost.

Do you have a pump for the shower or is it just gravity on its own?

how do you know its 2.85Kw/element

Brego888

John.G wrote: »

Is it warm/hot at the Myson TRV (white valve), if so or even if not just turn the white knob clockwise to its stop,this will prevent any chance of losing heat through the coil and boiler system, put it back to its original setting (5?) when you flash up your boiler again.

So is that valve only relevant when the boiler is being used to heat the water? And no the pipe around that valve is stone cold.

Brego888

John.G wrote: »

how do you know its 2.85Kw/element

Assume because of the cap photo I put up earlier

http://imgur.com/qs32tjU

John.G

Brego888 wrote: »

Assume because of the cap photo I put up earlier

http://imgur.com/qs32tjU

Sorry, I didnt pick up on that photo so it all goes back to your original query of why things have changed. (the reason I asked you to check the white myson valve was in case there was any reverse circulation induced in the coil from the hot water in the cylinder) Now that we know the exact immersion element power ratings we can do a few more calcs to try and figure out the mystery. If the electrician wired as he said..ie bath element only on then that will heat 75 litres (from 10C) to 26C or 95 litres to 23C in 30 minutes, both of those temperatures are only tepid and you would notice it straight away, now maybe he wired the sink immersion in permanently and if he did then this will heat (from 10C) 40 litres to 41C which is grand for showering and this would explain what is going on if you now had just cold water from the immersion if the sink element has failed BUT you still have hot water but it only lasts half the time. The only fit for all this is that the two elements are wired in parallel (both on) and the bath element has failed or there is no power to it. Assuming you had both elements working together for the last four years then they wold have heated (from10C) 75 litres to 43C or 95 Litres to 36C, in practice the amount of water being heated is probably somewhere between 75 & 95 litres as we dont know the diameter of the cylinder so the temperature was probably some way between the two, say 40C which was perfect showering temperature and you had somewhere around say a volume of 85 Litres at this temperature. Now you are gone to "1/2" so it can only mean to me at any rate that you are now running on the sink element only with the water temperature around the same at 41C but only with a volume of around 40 litres.
The sink element will heat 40 litres to 60C in 49 minutes and give you 67 litres of water at 40C when mixed with cold water at your shower, so again I would advise to set your timer to 1 hour and see what happens until you can get the wiring checked out.

It should be relatively easy to see what way the elements are wired up.

Brego888

Cheers for that.

Heating it for an hour definitely works and is certainly enough for a shower. That's what the missus has been doing now the past 2 weeks where as I can just about get away with a really really quick shower with the 30 minutes!

So when you say I need the wiring checked what exactly needs checking or what do I need to ask an electrician to do?

John.G

Brego888 wrote: »

Cheers for that.

Heating it for an hour definitely works and is certainly enough for a shower. That's what the missus has been doing now the past 2 weeks where as I can just about get away with a really really quick shower with the 30 minutes!

So when you say I need the wiring checked what exactly needs checking or what do I need to ask an electrician to do?

Check the resistance of each element first, they should each be ~~ 18/19 ohms, then check the wiring set up and if incorrect get him to wire it properly so that either the sink or bath can be selected when wired through the timer.

Brego888

John.G wrote: »

Check the resistance of each element first, they should each be ~~ 18/19 ohms, then check the wiring set up and if incorrect get him to wire it properly so that either the sink or bath can be selected when wired through the timer.

OK, might need someone more skilled than me for that!
So is the concensus that this is an electric problem as opposed to a plumbing issue?

RebelButtMunch

Brego888 wrote: »

OK, might need someone more skilled than me for that!
So is the concensus that this is an electric problem as opposed to a plumbing issue?

Sounds like it. I think we've ruled out hot water going elsewhere and the shower output hasn't changed