water in the terminal of immersion heater

[Caren Mccabe]

hi does anyone know possible cause of water in the terminal of immersion heater? electrician said he never saw this problem before and suggests a heating/plumbing expert but has disabled it till plumber is able to call......no hot water and this has only happened since wood burning central heating stove installed in march....terrible overflow prob from loft....is it related? Thanks for any help or info

 

[ruston]

More than likely if the tank is under the leak. Your overflow is probably because the expansion tank can not cope with the output of the wood burning stove and is causing it to fill and either flow out the overflow pipe or come over the top of the tank. Your electrician is right to advise you to get a heating engineer as this could be a potential scalding problem if this is what is happening.

 

[Caren Mccabe]

thanks for now.....plumber due Thursday and electrician Friday so wanted some knowledge before discussing plans for repairs etc! will try to get my head around this before they blind me with science!

 

[ruston]

Well if it is a gravity system there will be a cold fill water tank in the loft to replace the hot water you draw off. Wood burning stoves produce a tremendous amount of heat and can overheat the water in your cylinder which in turn transmits the heat to the header tank , which then expands and flows out of the overflow. In extreme circumstances the water can become as hot as the water in the tank and if the header tank is plastic this can collapse and flood your house, or even worse scald someone underneath it. Safety measures should have been put in place to prevent this happening, but as you are having overflow problems it dose'nt look like it.

 

[MarkieSparkie]

Heed the sound safety advice above and please don't use the wood burning stove or immersion heater until such time as plumber and electrician indicate it's safe to do so.
I have experienced this type of fault on a simple immersion heater system, it was caused by a pin hole in the end of the thermostat pocket, which only weeped when the tank was hot causing condensation/moisture to form on electrical contacts and cap of the immersion heater. This is probably not the most likely cause in your case considering the overflow problem you also experiencing, but it does illustrate that other unrelated causes are possible.

 

[snowhead]

The only cause of water in the terminal section of the immersion heater is is as above, pinhole or other leak thro' the element.

The heater needs replacing.
Heaters fail this way thro age, it's not uncommon.
It may have been worsened by the overheating.

The overflowing and overheating is probably faulty design of the system with the wood burner or it may just need the float valve adjusting.

Who designed and installed the woodburner, they need to come back and sort it out?

Does the hot water from the tap get very hot and steam??

If above is yes the system is in a potentially dangerous state.

The header tank that's overflowing should be a galvanised tank not a plastic tank.

 

[oldtimer]

Can I ask if it is a standard UK immersion or is it a non standard european I think Mega Flow system ? because I have had this with a couple of non standard units. Will try and dig up the info.

As above it called an Atlantic mega flow where the water leaks out off the element casing but it is actually the tube that is at fault ie the element is down to earth and the tube looks like it is sweating inside. By the way Atlantic UK are bust but I have the contact details of the agent also a lot of these were speced for a lot of Barret flats/houses

 

[oldtimer]

Any reply to this ?

 

[ruston]

Any reply to this ?

She might get back after the plumber and spark have been, Thursday and Friday respectively.

 

[rsp84]

Havent any experiance in wood stoves really, but if theres a header tank, (not the cold feed to the cylinder) then the overflow (which pokes out of loft to outside) would suggest a fault with the ball valve float sticking open.
If its the vent pipe of the cylinder into the cold feed tank then there maybe an overheating of the water or a possible blockage in the system and its pumping over rather than cycling the heat round(even possible that the height of the vent pipe was never calculated accuratly and is inadequate for the wood stove)

 

[oldtimer]

Caren it could be the wood burning stove is boiling the water in the immersion I take it there is some sort of heat exchange in the woodburner that uses a gravity feed if this is the case then I take it the bubbling out of the vent pipe is when the wood burner has been on for 2-3 hours so in a sense you have a big kettle on your hands because you have no temperature control.

So when you run the hot tap during the bubbling does it come out scalding hot ? If so you need some sort of heating control if you go back a few years like me the coal fire used to do the same job but only if you redirected the heat going up the chimney to a heat exchanger behind the fire when or if the immersion got up to heat you redirected the heat back up the chimney so it could be that your wood burner does not have this facility although this could be handy in the winter if you redirected this to the CH system.

Just to add you could be getting a leak if you are bubbling as you put it the immersion tank that is meant to control at 60-65oC instead of 100oC (boiling point) and at that temperature things can expand to develope a leak

 

[rsp84]

Hopefully there will be a high limit stat, stops the water boiling (eps dangerous if the feed tank is made of plastic as there been cases of it melting and taking ceilings down).

 

[oldtimer]

Havent any experiance in wood stoves really, but if theres a header tank, (not the cold feed to the cylinder) then the overflow (which pokes out of loft to outside) would suggest a fault with the ball valve float sticking open.
If its the vent pipe of the cylinder into the cold feed tank then there maybe an overheating of the water or a possible blockage in the system and its pumping over rather than cycling the heat round(even possible that the height of the vent pipe was never calculated accuratly and is inadequate for the wood stove)

In Scotland the vent or the expansion pipe is vented out on to the roof ie the pipe is shaped like a swan neck but my understanding that in England some of these pipes vent into the cold water tank not a problem if immersion is ok but when the stat fail it can boil and worse still if the cold water tank is plastic this to can boil then split.

Be aware an infant died a few years ago due to this and i am not sdure but I think that was the reason for fitting a high limit cut out switch on the control stat

 

[rsp84]

+1 old timer, and sorry didnt realise there maybe different installs in scotland. I guess down here we like recyling the venting water :laugh:

 

[ruston]

Hopefully there will be a high limit stat, stops the water boiling (eps dangerous if the feed tank is made of plastic as there been cases of it melting and taking ceilings down).

Simply put if it is a gravity fed system there will be two header tanks , both will overflow externally, however both have expansion pipes fed into the respective header tanks . If the water to either the domestic or heating water is allowed to run unregulated the hot water will expand into one or both of the tanks and can easily expand to the top of the tank reaching boiler temperature.I have seen the external overflow not be able to cope and hot water erupt over the top of the tank and come down through the ceiling. As Old timer has said the old style back boilers had no regulators other than a damper and it was common to boil the hot water in the cylinder, the remedy in those days was to run the hot water off. Hope this helps a bit.

 

[oldtimer]

+1 old timer, and sorry didnt realise there maybe different installs in scotland. I guess down here we like recyling the venting water :laugh:

No your just lazy lol

But seriously when cold water tanks were lead lined or galvinised this was not a problem as the water in the tank would boil up then vent to outside but sadly for this child the tank was changed to plastic eventually split because the stat in the immersion was faulty and welded itself closed hence the kettle analogy . Now this is a common fault and people see a problem when the water comes out the taps scalding that why they changed the regs to include a high limit cut out stat within the thermostat so when I get a call that the immersion is not working I carry 2 stats with safety cut outs .

Just to add although we live in the UK there is a lot of differences between Scotland and England with regards to Laws and building regs the only oddity is MOD family houses as these are built off plan to English standards and because its on MOD land then it does not have to comply to the Scottish building standards

 

[rsp84]

No your just lazy lol

But seriously when cold water tanks were lead lined or galvinised this was not a problem as the water in the tank would boil up then vent to outside but sadly for this child the tank was changed to plastic eventually split because the stat in the immersion was faulty and welded itself closed hence the kettle analogy . Now this is a common fault and people see a problem when the water comes out the taps scalding that why they changed the regs to include a high limit cut out stat within the thermostat so when I get a call that the immersion is not working I carry 2 stats with safety cut outs .

Just to add although we live in the UK there is a lot of differences between Scotland and England with regards to Laws and building regs the only oddity is MOD family houses as these are built off plan to English standards and because its on MOD land then it does not have to comply to the Scottish building standards

Probably cause the Scottish Builiding Standards are better regulated and possibly tougher/more expensive to impelment. And yeah, ive been told of the child passing story before,very sad indeed.

 

[Caren Mccabe]

sorry no idea! waiting for all the experts to get here and assess damage....thanks for posting!

 

[ruston]

sorry no idea! waiting for all the experts to get here and assess damage....thanks for posting!

Please let us know what the outcome is.

 

[Caren Mccabe]

thanks for all advice! engineer coming out Monday so may be clearer then.....will keep you posted! we have metal tank above immersion and plastic one in the loft (the loft one is the overflowing one) do we need a metal one in loft too? I think the immersion is over 30 years old so may be kaput! Thanks again...I will let you know what's what as soon as I know more!

 

[ruston]

Thanks for keeping us informed. Your engineer on the site will be in a position to assess better than us. Is the water coming over the top of the tank into the loft or is it coming out of the overflow pipe to the outside of the building? If it is excessive heat that is causing the overflow he will design it properly for you.

 

[oldtimer]

Well getting a metal cold water storage tank is not going to happen as plastic is king and as thought the expansion pipe from the immersion does vent into this tank this was safe enough when it was metal and if it was the immersion that was giving the problem then I would have said change the control thermostat for one with a safety cut out on it.

But you have a wood burner that is acting a bit like the old draw coal fire setup but in that case you could redirect the heat back up the chimney as a form of control and thats the key to the wood burner nothing wrong with it heating the water in the immersion but there needs to be a proper automatic temperature control that switches this function off when the immersion gets up to temperature.

As for the vent pipe well up here that would not be allowed as this is the fail safe system ie if the electric immersion heater or central heating or A N Other heat source fails and ends up boiling the water then all you would see is steam blowing or venting to the outside instead of plastic cold water tank collapsing with the heat and flooding the property with hot water so if you are going to all of this trouble then get it vented to the outside then you can sleep at night

 

[Caren Mccabe]

the water is flowing out of the building down the outside wall but the immersion heater has water in the cap so not sure where water is coming from....don't understand the flow through the house and am thoroughly confused with talk of tanks everywhere! plastic tank in loft where overflow to outside, metal tank above immersion tank in bedroom....not sure where the water in the immersion top cap came from and central heating wood burner stove on ground floor with pipes leading upstairs to immersion AND up again to loft (I think?) Don't even know if it's a plumbing or electrical problem but seems related according to the general electrician that came out.....Thanks for advice...will let you know!

 

[MarkieSparkie]

Caren, can you clarify one point for me, when you say a metal tank above the immersion tank, do you mean a second copper tank sat directly above the copper immersion tank as part of an integrated unit?

 

[oldtimer]

Caren, can you clarify one point for me, when you say a metal tank above the immersion tank, do you mean a second copper tank sat directly above the copper immersion tank as part of an integrated unit?

Mark I think this is the central heating expansion (small) tank

Caren some pictures would help

 

[MarkieSparkie]

Mark I think this is the central heating expansion (small) tank

Caren some pictures would help

That was my initial impression too mate, but just wondered if we all making the same, possibly 'wrong?,' assumption from Caren's description.

 

[oldtimer]

Yep a couple of pics would be nice

 

[Caren Mccabe]

the metal tank above the copper immersion is a silver metal tank that will need replacing soon as advised due to a white powdery residue appearing on the sides....apparently a sign of corrosion? what significance is it that it's an expansion tank? what does that mean? The overflow pipe is coming directly from the other plastic tank on the floor above (loft)....I will try to put some photos up of all tanks, thanks for your concerns and help....I started as a novice but hopefully will pick up a few tips that may help in future but hopefully will not be needed!! I am interested in what wrong assumption is being made from my descriptions cos I need to make sure I'm saying the right things to get this sorted asap! Ta for now!

 

[Silly Sausage]

Have you tried these boys yet?

Plumbing Forum | Plumbing Advice | Plumbers Forums | A forum for plumbers advice in the UK

 

[Caren Mccabe]

if my immersion tank (copper cylinder one) needs replacing do I get plumber or electrician? My local electrician said seek advice from plumber before he can re connect the immersion so I'm unsure who to speak to re a replacement if it's needed... ta!

 

[Silly Sausage]

if my immersion tank (copper cylinder one) needs replacing do I get plumber or electrician? My local electrician said seek advice from plumber before he can re connect the immersion so I'm unsure who to speak to re a replacement if it's needed... ta!

I would say a plumber myself.
Post a link to this thread on their forum and I'm sure you'll get plenty of good advice.
To go with what you've had already!

 

[ruston]

You need a plumber to sort out the overflow problem. I may have got the wrong impression , I thought you had water damage in the loft due to the overflow. Is this the case?

 

[oldtimer]

All hot water systems have an expansion tank so your immersion is fed of the cold water tank in the attic then there is the central heating system this needs it own expansion tank so this should be small ie 600mm wide by 500mm high 500mm deep and if it is an old system then it will be metal.

When a heating system get hot it expands hence why the tank is called an expansion tank and it has to be seperate from the domestic water system.

Your immersion should have 2 ways of heating it one is electric the other by another source ie a central heating system or a coal fire or as you say a wood burner so how do you control it well the electric heater in the immersion should cut off via the control thermostat in the element now you say there is water leaking out of this well this could be due to wear and tear or the water in the immersion being boiled and this tip of heat can expand the metal joints causing leakage.

The other thing is the wood burner if it is heating the water by what is called gravity circulation you will know this if the pipes going into the side of the tank are large ie 28mm wide so whats the problem well if it was a central heating boiler the water would heat up to the same as the control stat on the boiler ie 65oC then it would cut out fine but if it is this wood burner that is constantly on then you need to find out if this can switch off heating the water when it gets to a set temperature.

Also history ie how long as it been in have you always had really hot water or has this problem just arised and does it also heat the central heating as well. As for plumbers and electrician you need a plumber as he will sort or renew the immersion and should be able to fathom how the wood burner works and controls the water

 

[Caren Mccabe]

originally called electrician cos copper immersion tank tripped all electrics due to water in terminal cap but he recommended plumber to seek where the water came from....the overflow was stemmed by us via a valve on the pipe near ballcock and electrician thought the overflow may be connected to excess water in terminal due to build up of pressure from stemmed overflow...plumber came today and said copper immersion may be breached inside hence water in cap....we are still unsure if the stove and its water flow etc is functioning and not sure if that is what damaged the cylinder with excess heat....the installer is coming out as soon as he can but I am not using either the appliance or immersion at present! Thanks for all advice....I will be recommending this site to everyone I know and I will be trying out the plumbing forum next!!

 

[oldtimer]

Caren I will try and do a schematic for

Sorry I should have added that I googled the above as it gives a good idea

 

[Caren Mccabe]

wow!! you are so kind to go this far with your help even though my original electrical problem has morphed into plumbing one! I am very grateful to all those who have taken the time to post and will let you know how it pans out as soon as it's all done....Thanks for now!

 

[oldtimer]

No Probs it keeps the brain ticking over with all that you have said my thinking is the temperature control for the wood burner heating the immersion is faulty causing the immersion boil off in other words a big kettle plus the immersion is designed to work at temperatures of 55-65oC so boiling it at 100oC can put strain on any joints hence the leaking.

I also think that this would not be such a big problem on a central heating system where the boiler temperature cuts of at say 65-70oC the problem would not have been noticed except you would have had an abundance of hot water