Nightmare

[5hane]

Hi 

Tthis is my first post. Im sorry that it might look like a rant, but it is simply what has been going on with my hot water over the last few years:
 

3 years ago my hot water tank stopped heating water. It took a week for the housing association to send out a contractor because it was the Christmas holidays and they didn’t class having no hot water as urgent.
 

When the contractor arrived he discovered that the element had failed in what was a 20 year old un-insulated tank. This apparently was a very good innings for such an old tank.
 

Anyway, the tank was replaced as was the dual top loading immersion.
 

After that I was only getting half a tank of hot water over night. The boost only gave me ¼ of a tank.
 

Eventually another of the housing associations contractors came out and replaced the dual element for a longer one, although he managed to crease the tank at the same time, which meant another new hot water tank had to be fitted.
 

Over the next few years I have called out numerous electricians (some the housing associations and some privately) because I was waking up to no hot water due to stats burning out and or tripping over night.
 

As it stand for the last few years I have been setting my alarm for 1am every night so that I can check if the water is heating up, and if not, trying to reset the over night stat. This usually results in a few sparks coming off the stats as well as a serious lack of sleep and becoming very down on myself having put up with this problem for so long.
 

Last week the housing association contracted out electricians to completely rewire our homes. The contractor were amazing: brand-new heating, extractors and they even installed a shaving light and heated towel rail that I had purchased.
 

Sadly when it came to the hot water, things went bad yet again. The following day after they finished I had no hot water. Neither the boost or over night stats worked, even though the contractors showed me that power to both stats was live. The contractor came out again the following day to rewire the heating controller and the stats.
 

As it stands, the boost works and the over night stat fires up, but only when I push the reset button on the stat itself, again resulting in a few sparks.
 

So far I have had 2 water tanks, 2 dual elements and countless stats fitted. Plus I am constantly worried about waking up to no hot water before I go to work each day.
 

So, if the problem isn’t the tank, the element or the stat, what the hell is going wrong?
 

I always used to think that hot water was a basic necessity, but apparently it’s a luxury.
 

What is my next move, because I love my home and am very house proud, but this one problem is effecting my life, which I guess to some people will think is an overreaction?
 

Is it normal for me to be fiddling around with stats at 1o’clock in the morning everyday for so long?
 

Calling out an electrician also involves having to take leave from work, and of course they only ever turn up when they say they will about half of the time, and when they do decide turn up to carry out the work, the problem is never properly dealt with!
 

I’m no expert but I didn’t it would take a rocket scientist to make hot water flow from my taps.

Please can anyone guide me?

Thank you

 

[ProDave]

Actually I believe the fault IS the design of the water tank.

I have had numerous problems with top mounted immersion heaters.  The problem is that now, in addition to the normal thermostat, they must also have the secondary over temperature cut out, the little red button you have been resetting.

Now it seems to me, that often, the secondary cut out, has it's sensor right at the end of the element, whereas the normal thermostat has it's sensor further along.

For a top mounted heater, the consequences seem to be, the over heat trip will pop, before the normal thermostat trips.

I have never found a solution to this, other than replacing the cylinder with one that has two heating elements from the side.

I did one of these last year where after constant trouble, I convinced the owners to pay for a new tank, and have had no trouble since fitting a new side element tank.

Perhaps EVERY time it trips, rather than you resetting it, you should contact your landlord and let THEM pay for the expense of sending someone to reset it.  EVERY time they come, show them the link to side heated tanks, and eventually, they just might realise, it is cheaper to send someone to replace the tank, than it is to keep on sending someone to reset the trip again and again. Keep telling your landlord, the solution to the constant tripping is a tank with two elements entering from the side.

Here you go this is the one I fitted to solve that issue  http://www.tdlonline.co.uk/Products/Heating/Hot+Water+Cylinders/Hot+Water+Copper+Cylinders/Direct/item1287?startPos=

I chose that one, because it was one of only a few small cylinders that had two side mounted immersion heaters. It's easy to find two side mounted heaters in larger cylinders, but a lot of manufacturers only give you one top port in their smaller cylinders forcing you to use a dual top mounted element with the problems you have found.

 

[5hane]

Thanks for your reply ProDave
 

I seem to remember being told by one of the contractors that my tank needs to be dual element due to the tanks positioning:
 

The tank sits in the same cupboard as the cold water storage tank and that the space is so confined that the tank would have to be removed if anything other than a top mounted immersion or stat needed to be removed.

Also, from a personal point of view (and I know this probably sounds silly),I hate the major upheaval that comes with a tank being replaced (this would be the third time): messed up carpets and decorating, and the chance of more substandard work by the housings contractors anyway.

It sounds crazy that a very old dual immersion tank can run fine for 15+ years with no problems, but anything similar now fails.

 

[ProDave]

Again, that's why I posted the link I did to that small dual side element tank.  Surely there's a door in front of the cupboard, so as long as the tank is positioned with the heaters on the front facing the door, there is not problem changing them if needed (I HAVE seen tanks positioned so the heating element faces a wall so not possible to change them, but that's just plain poor installation)

And a competent installer should not mess up your carpets changing a cylinder. Did they forget to drain it properly?

The reason your OLD thermostat worked for so long, is when that was made, there was no requirement to have this secondary over heat cut out.  It's the secondary cut out that seems to give all the problems. But it's now illegal * to sell them without the secondary cut out.

The only other option is to keep trying different makes of thermostat, until you might one day eventually find one where the over heat cut out does not needlessly trip when top mounted. And if you find one that actually works, please please tell us so we al know a solution to this common problem.

The reason your tank is dual element is for the bottom heater to heat the full tank overnight at the cheap rate, or for the boost to heat half the tank at the peak rate if needed.  Those "dual" elements can be either a single dual element in from the top, or two single elements in from the side.

* interesting point for discussion.  It may be illegal to make them now without the secondary cut out, but would it be illegal to search the likes of ebay for an old thermostat without the secondary cut out and fit that.?  Discuss.

 

[SLIPSHOD & SLAPDASH]

Agree with Dave but should add the thermostat is independant to the element, it  slides into the element housing, so it can be changed without having to drain down or any plumbing needed .

I read the rule, and have asked the NIC about the duel stat when carrying out inspections . The duel safety stat is only needed when a plastic expansion tank is fitted. But with all the cheap crap now its a good idea to have one.

 

[ProDave]

Agree with Dave but should add the thermostat is independant to the element, it  slides into the element housing, so it can be changed without having to drain down or any plumbing needed .

I read the rule, and have asked the NIC about the duel stat when carrying out inspections . The duel safety stat is only needed when a plastic expansion tank is fitted. But with all the cheap crap now its a good idea to have one.

That's interesting re plastic header tanks.

So does that mean anyone sells single thermostats now without the exttra safety cut out?  It certainly would have prevented me doing that cylinder swap as they still had a galvanised steel header tank.

 

[SLIPSHOD & SLAPDASH]

From memory,  the change was brought in due to plastic expansion tanks deforming due to the hot water being dumped in them from the hot cylinder, nearly always due to a  stuck thermostat in the immersion.  I  think the double stat rule is for all new/replacements though.  With a steel expansion tank  Its only a remark on a EICR but a code 2 if plastic

 

[ProDave]

Personally I think building regulations should prevent a cold water header tank from being placed above a bedroom.  Place it above a bathroom where it's unlikely anyone will be sleeping. Directly above a bath would be good, as when the bath is occupied, you will have drained a lot of hot and cold water off, so it's virtually impossible for the tank to boil and melt the header tank, unless you have a very looooong bath.

This all stems from a case a few years back when a child died after the plastic tank above his bedroom ruptured pouring scalding water on him.  As always we tweak things here and there, but never fix the root cause, which was the location of the tank.

And the "poor" design of these new thermostats that keep nuisance tripping when used with a vertical element will only encourage people to bypass them. But do we hear any of the professional bodies looking into this to try and ensure they do work reliable with a vertical element?

 

[SPECIAL LOCATION]

The reason your OLD thermostat worked for so long, is when that was made, there was no requirement to have this secondary over heat cut out.  It's the secondary cut out that seems to give all the problems. But it's now illegal * to sell them without the secondary cut out.

* interesting point for discussion.  It may be illegal to make them now without the secondary cut out, but would it be illegal to search the likes of ebay for an old thermostat without the secondary cut out and fit that.?  Discuss.

But... is it "Illegal"  ????

Or just, as with many electrical requirements, guidance for good practice and open to interpretation and others methods to achieve a similar level of safety are acceptable? 

Water regs advisory stuff..

http://www.wras.co.uk/PDF_Files/Scalding%20information%20note%20Jan%2008.pdf

HSE guidance..

http://www.hse.gov.uk/services/localgovernment/hotwatersystems.htm

Approved Doc G page 16-> ish onwards...

http://www.planningportal.gov.uk/uploads/br/BR_PDF_AD_G_2010_V2.pdf

Basic safety principal as I see it is the recommendation for TWO methods of preventing the cylinder from overheating..

1.. Standard thermostat

2.. A.N.Other disconnection device...

If these manual reset trips are causing more inconvenience than good...

{thinking about minimising inconvenience.. etc..?}

Then couldn't a standard C/H tank stat with a contactor to remove power from the element be a second way of preventing overheating as a secondary fail safe??

I'd be interested to see the wording of the LAW (if it is LAW) that says you cannot for single thermostat elements??

Especially as TLC Still sell Bog-Standard Thermostats..

with the comment..

Only if you have secondary protection..

http://www.tlc-direct.co.uk/Main_Index/Water_Heating_Index/Immersion_Heaters_2/index.html

 

[Wilpickard]

I'm glad this topic has come up,although I've not got a solution to give you I've experienced the same problem in my house. At the time when this was happening the cylinder was only in a tempory position as we was knocking he house to bits.

Ours kept tripping the overheat stat so I just knocked the normal stat right down (bout 55)

My theory was that in the cylinders where the element is loaded fom the top, (like ours) all you needed was a small but of air to build up in the top while bing used, this would cause the element to overheat for a short time, causing the overheat stat to kick in.

 

[SPECIAL LOCATION]

My theory was that in the cylinders where the element is loaded from the top, (like ours) all you needed was a small but of air to build up in the top while bing used, this would cause the element to overheat for a short time, causing the overheat stat to kick in.

The concept of air locked in the cylinder itself would on the face of it appear ilogical...

i.e.

The hot water normally exits the cylinder through the pipe coming out of the top...

If it were designed so that air could get trapped in the top of the cylinder then the cylinder would never ever fully fill up in the first place..

If there is an air problem, it would also have to involve the outlet pipe.. 

which would typically also manifest itself with flow problems at the hot taps..

If flow is good at the taps then air shouldn't be an issue IMHO..

By their very nature surely the insides of all water cylinders has to slope upward toward the exit pipe position.. 

otherwise how or where could you bleed any trapped air out of the cylinder???

?? :C

 

[Wilpickard]

I know exactly how a hot water cylinder works and also know they shouldn't get air in. But as the waters flowing though it, leaving the cylinder at the top and being filled at the bottom, the currents in the water will be swirling around, bubbles at be created which will rise to the top, when the element is heated its relying on the water to cool to down and regulate it, once that water is missing, no cooling, so the temp at the element would shoot up?

It's only a theory, so mr special location I don't see why you felt the need to pull my post apart?

I see you've come up with a solution to the problem with another stat, I assume a cylinder stat? (What's the current rating of them by the way?) but you've not suggested any reasoning why its happening?

Feel free to message me. Or email. Screen name at aol dot com

Will

 

[SLIPSHOD & SLAPDASH]

Personally I think building regulations should prevent a cold water header tank from being placed above a bedroom.  Place it above a bathroom where it's unlikely anyone will be sleeping. Directly above a bath would be good, as when the bath is occupied, you will have drained a lot of hot and cold water off, so it's virtually impossible for the tank to boil and melt the header tank, unless you have a very looooong bath.

.

The various  cold water tanks always used to be placed over the hot water cylinder, to help avoid freezing in the cold weather. Its only in more recent years any part of the plumbing gets pushed to any availible space.

 

[utterlyfab]

Thats a nightmare for sure