Immersion losing heat

Brego888

Hi all, I'm not sure if this is a plumbing or electrical question.
Over the last couple of weeks we've notice the amount of hot water we can get for a shower from our normal immersion setting has decreased. It starts warm but becomes cold much quicker than usual.

I think I can track this back to when I removed bathroom towel radiators a couple of weeks ago for painting. I obviously had to reintroduce some water back into the system when running the gas boiler again to refill the radiators and bleed all the air out.

I used the pressure gauge near the hot water tank to refill the system. I'm regretfully not sure where the turning valve was positioned before I started the process and feel where it is now might be letting cold water into the tank when the immersion should be heating the water. The valve has an "A" turning one way and a "C" turning the other. I've tried fully turning each way and somewhere in the middle with no help each time I use the immersion.

Does it make sense that this might be affecting the water or am I way off?

http://imgur.com/WkFywLo
http://imgur.com/p0KHGg7
http://imgur.com/4AOW3bT

Sleeper12

Where you run the out of of hot water in the shower do you have hot water water elsewhere?

It could be a the shower itself.

Sleeper12

Can you post a photo of the shower

Brego888

Sleeper12 wrote: »

Where you run the out of of hot water in the shower do you have hot water water elsewhere?

It could be a the shower itself.

Just very lukewarm water left in the taps as well.
We have 2 showers, one in the main bath and on in en suite. Both affected the same.

http://imgur.com/Nuu0gSE
http://imgur.com/qVMWMNm
http://imgur.com/yJgK3NB

John.G

Brego888 wrote: »

Hi all, I'm not sure if this is a plumbing or electrical question.
Over the last couple of weeks we've notice the amount of hot water we can get for a shower from our normal immersion setting has decreased. It starts warm but becomes cold much quicker than usual.

I think I can track this back to when I removed bathroom towel radiators a couple of weeks ago for painting. I obviously had to reintroduce some water back into the system when running the gas boiler again to refill the radiators and bleed all the air out.

I used the pressure gauge near the hot water tank to refill the system. I'm regretfully not sure where the turning valve was positioned before I started the process and feel where it is now might be letting cold water into the tank when the immersion should be heating the water. The valve has an "A" turning one way and a "C" turning the other. I've tried fully turning each way and somewhere in the middle with no help each time I use the immersion.

Does it make sense that this might be affecting the water or am I way off?

http://imgur.com/WkFywLo
http://imgur.com/p0KHGg7
http://imgur.com/4AOW3bT

When you say immersion are you talking about a electric immersion or the water heating from your boiler??

Brego888

Electric immersion. Don't use the boiler at all this time of the year.

John.G

Brego888 wrote: »

Electric immersion. Don't use the boiler at all this time of the year.

The pressure gauge thats showing 1.5 bar is correct and is the pressure in the boiler water/expansion vessel system and when the boiler is on it circulates water in a coil in your cylinder that heats the water in the hot water cylinder, it has no direct contact with the contents of the hot water cylinder so any adjustment to that 1.5 bar pressure wont affect it except that you have a hole in the heating coil, highly unlikely. The white Myson TVR controls the temperature of the hot water by opening/shutting a valve in the hot water boiler circuit.

Electric immersion: some cylinders have a dual immersion with a switch marked Bath/Sink and will heat depending on which is selected either 50 Lires or around 100 litres of water. I dont know what size cylinder you have or where the heating elements are but a 3 kw immersion will take 5.8 Kwh per 100 litres of water to 60C from 10C and depending on its location can take from 0.5 hrs to 3 hrs to fully heat up the water. Its likely that yours is heating at least 150 litres to 60c which will take 3 hours. This 150 litres at 60C will give you 250 litres at 40C (factor of 1.66).So if you can make sense of this and see where the heating element(s) are located you should be able to figure out how much hot water is available to you.

Brego888

Thanks for your reply. It is a relatively new tank only installed 4 years ago. It came with a dual bath/sink switch. During installation a timer was put in and the setting permanently fixed to bath. Never had any issues.

How do you explain the recent drop in volume of hot water though? I've only ever needed 30 minutes to heat it for a shower. Now 30 minutes gives me about half the hot water I previously had.

John.G

Brego888 wrote: »

Thanks for your reply. It is a relatively new tank only installed 4 years ago. It came with a dual bath/sink switch. During installation a timer was put in and the setting permanently fixed to bath. Never had any issues.

How do you explain the recent drop in volume of hot water though? I've only ever needed 30 minutes to heat it for a shower. Now 30 minutes gives me about half the hot water I previously had.

Assuming you have around a "23 ins" bath element then depending on the diameter of your hot water cylinder you are probably heating around 75 litres of water and maybe up to 95 litres.
lower figure of 75 litres means that in 30 minutes will raise the water temperature by 17C which ends up as a hot water temperature of (from 10C cold water) 27C...not much good for having a shower

Higher figure of 95 litres means that in 30 minutes will raise the water temperature by 14C which ends up as a hot water temperature of (from 10C cold water) 24C...less than useless.

So I really cant comment except to say that if the sink immersion was in use for 30 mins you would heat say 40 litres to 42C, a acceptable temperature for about a 4 minute shower. I can only suggest that you leave the immersion on for at least one hour, this gives 75 litres @ 44c and 95 litres @ 37C

Sleeper12

John.G wrote: »

Assuming you have around a "23 ins" bath element then depending on the diameter of your hot water cylinder you are probably heating around 75 litres of water and maybe up to 95 litres.
lower figure of 75 litres means that in 30 minutes will raise the water temperature by 17C which ends up as a hot water temperature of (from 10C cold water) 27C...not much good for having a shower

Higher figure of 95 litres means that in 30 minutes will raise the water temperature by 14C which ends up as a hot water temperature of (from 10C cold water) 24C...less than useless.

So I really cant comment except to say that if the sink immersion was in use for 30 mins you would heat say 40 litres to 42C, a acceptable temperature for about a 4 minute shower. I can only suggest that you leave the immersion on for at least one hour, this gives 75 litres @ 44c and 95 litres @ 37C

Totally agree. We've a boost button on our immersion & we'd ave it on for an hour before each shower. If the tank was stone cold we'd boost for 2 hours


I'm changing my boiler soon & will have a dedicated hot water zone. Gas heats water at roughly half the price of electricity

Wearb

Is there any chance that your boiler was contributing to your hot water cylinder heretofore? And not now that your heating is turned off.

Brego888

John.G wrote: »

Assuming you have around a "23 ins" bath element then depending on the diameter of your hot water cylinder you are probably heating around 75 litres of water and maybe up to 95 litres.
lower figure of 75 litres means that in 30 minutes will raise the water temperature by 17C which ends up as a hot water temperature of (from 10C cold water) 27C...not much good for having a shower

Higher figure of 95 litres means that in 30 minutes will raise the water temperature by 14C which ends up as a hot water temperature of (from 10C cold water) 24C...less than useless.

So I really cant comment except to say that if the sink immersion was in use for 30 mins you would heat say 40 litres to 42C, a acceptable temperature for about a 4 minute shower. I can only suggest that you leave the immersion on for at least one hour, this gives 75 litres @ 44c and 95 litres @ 37C

But leaving it on for an extra half an hour doesn't explain why I haven't needed to do that previously. 30 minutes has been fine for the last 4 years.

Brego888

Wearb wrote: »

Is there any chance that your boiler was contributing to your hot water cylinder heretofore? And not now that your heating is turned off.

No not really. I only use the gas to heat the water for 3 or 4 months of the winter. For the rest of the year I only use the immersion and it has never been a problem up until recently.

John.G

Brego888 wrote: »

No not really. I only use the gas to heat the water for 3 or 4 months of the winter. For the rest of the year I only use the immersion and it has never been a problem up until recently.

roughly how long was the showering time and was it one or two showers

RebelButtMunch

The rads and taps are separate especially if your only talking about only using the immersion. In terms of heat loss

If anything you should perceive more hot water now as the cold water is milder now this time of year.

By itself Is your hot water as hot as it used to be. Can you measure it?

John.G

Brego888 wrote: »

But leaving it on for an extra half an hour doesn't explain why I haven't needed to do that previously. 30 minutes has been fine for the last 4 years.

You say in previous post " During installation a timer was put in and the setting permanently fixed to bath." what does this actuallu mean?. Thermodynamically the only way that I can see you reaching a showering temperature in 30 minutes is if the heating elements were wired in parallel giving 5KW or 6Kw or whatever the elements power is, but as you say why should this change if you have touched nothing in the electrical set up.

Wearb

Brego888 wrote: »

No not really. I only use the gas to heat the water for 3 or 4 months of the winter. For the rest of the year I only use the immersion and it has never been a problem up until recently.

When did you turn off your gas heating/ Did it coincide with your shower temp drop?

Brego888

John.G wrote: »

roughly how long was the showering time and was it one or two showers

Used to get roughly 10 minutes out of either shower (but only 1 shower per 30 minute immersion use)
Now it's about 5 minutes or less

Brego888

RebelButtMunch wrote: »

The rads and taps are separate especially if your only talking about only using the immersion. In terms of heat loss

If anything you should perceive more hot water now as the cold water is milder now this time of year.

By itself Is your hot water as hot as it used to be. Can you measure it?

Not sure how I'd measure it. But it feels equally as hot as previously but only lasts half the time.

Brego888

John.G wrote: »

You say in previous post " During installation a timer was put in and the setting permanently fixed to bath." what does this actuallu mean?. Thermodynamically the only way that I can see you reaching a showering temperature in 30 minutes is if the heating elements were wired in parallel giving 5KW or 6Kw or whatever the elements power is, but as you say why should this change if you have touched nothing in the electrical set up.

The switch had a bath/sink switch when I bought it but the electrician but on a timer switch switch which doesnt have a bath/sink switch and he told me turning it on would heat the bath setting.
Anyway that doesn't explain why I only get half the heat that I used to get.

Brego888

Wearb wrote: »

When did you turn off your gas heating/ Did it coincide with your shower temp drop?

No I haven't used the gas in 2 months. This problem only starting in last 2 weeks

RebelButtMunch

Anyone on the thread know if Bath means bath and sink elements and perhaps OPs bath element is gone and he's on sink power only?

corks finest

Brego888 wrote: »

Thanks for your reply. It is a relatively new tank only installed 4 years ago. It came with a dual bath/sink switch. During installation a timer was put in and the setting permanently fixed to bath. Never had any issues.

How do you explain the recent drop in volume of hot water though? I've only ever needed 30 minutes to heat it for a shower. Now 30 minutes gives me about half the hot water I previously had.

As a normal guy,I'd investigate if it's air locked,or needs bleeding first,then check the element on the tank itself,they do go after a few years

BaZmO*

RebelButtMunch wrote: »

Anyone on the thread know if Bath means bath and sink elements and perhaps OPs bath element is gone and he's on sink power only?

That’s what I was thinking. Most elements in an immersion have two heating elements, a short one for the sink which only heats the top half of the cylinder, and a long one for the bath that heats up the whole cylinder. Judging what the op said about the way the timer was wired to only have the bath element on it could be the case that the bath element going/blowing and the sink element kicking in.

It’s also possible that the element has just tripped. Under the plastic cap on the element there should be a reset button. Push it in to see if it resets?

Sleeper12

Brego888 wrote:

The switch had a bath/sink switch when I bought it but the electrician but on a timer switch switch which doesnt have a bath/sink switch and he told me turning it on would heat the bath setting. Anyway that doesn't explain why I only get half the heat that I used to get.

Very possible electrician has it permanently on sink and not bath. This will heat less water but to the old temperature. So you will have hot water but not enough

It's a ridiculous set up limiting you to just bath. I've no idea why he'd do such a thing unless he made the mistake of putting the timer between the immersion switch and the immersion. It should be wired timer to immersion switch & immersion switch to the immersion. This will give you full control of bath and sink settings

Sleeper12

RebelButtMunch wrote:

Anyone on the thread know if Bath means bath and sink elements and perhaps OPs bath element is gone and he's on sink power only?

Put any money that the electrictrican has it wired up to the sink and not the bath. I'm betting he's a handyman and not an electrician

Brego888

BaZmO* wrote: »

That’s what I was thinking. Most elements in an immersion have two heating elements, a short one for the sink which only heats the top half of the cylinder, and a long one for the bath that heats up the whole cylinder. Judging what the op said about the way the timer was wired to only have the bath element on it could be the case that the bath element going/blowing and the sink element kicking in.

It’s also possible that the element has just tripped. Under the plastic cap on the element there should be a reset button. Push it in to see if it resets?

Yes this sounds like a good suggestion I might try re set it if I can get under the cap. Had watched a couple of videos of how to do this

Brego888

Sleeper12 wrote: »

Very possible electrician has it permanently on sink and not bath. This will heat less water but to the old temperature. So you will have hot water but not enough

But again this in itself wouldn't explain the recent drop in amount of hot water

BaZmO*

Brego888 wrote: »

Yes this sounds like a good suggestion I might try re set it if I can get under the cap. Had watched a couple of videos of how to do this

If that doesn’t work I’d say the elements are wired the wrong way around.

Brego888

BaZmO* wrote: »

If that doesn’t work I’d say the elements are wired the wrong way around.

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?

Sleeper12

The drop off in hot water is since the timer was installed. At least that's what I thought I read

Just rereading the thread now. Timers been there 4 years.

I'd get an electrician to test the voltage.