Scratching my head over immersion heater!

[ETradesmen]

Good evening all, I have a query regarding an immersion tank.

I received a call from a new client asking do I fix immersion tanks to which I told her it’s probably best to get a plumber out as he can eliminate the problem and change the element if required which would save her money.

I won’t go into too much detail but it turns out the plumber just changed the immersion element and billed her, the next day later she called me saying that it’s not working again, could I pop over?

After taking a look I soon realised that the timer was an old rotary time guard which isn’t ideal as it hasn’t got a boost function and which had also malfunctioned resulting in a previous DIYer bypassing it resulting in the immersion running 24hrs a day. (This has since been upgraded)

I tested the mains in at the tank which had voltage then nothing coming out of the thermal cut out which I reset then supplying voltage to the element (Could here it heating) I then assured her I had sorted the problem as I had changed the time clock and reset the thermal cut out.

I received another phone call the following day saying it’d stopped working yet again.The only thing left do was to change the thermal cut out for a new one which I did and it worked for 3 days only to trip again today!

I have done way more than I would normally do and this job has cost me money!, I’ve since walked away from the job on good terms explaining to the client I can’t do anything else. In 20 years of doing this I am dumbfounded!

Any ideas on possible causes? I had made sure the thermal cut out was set no higher to 65 degrees? It is an electric only flat with a dual element mega flow type tank although the middle element isn’t being used at all as they don’t have eco7.

 

[telectrix]

Earlier posts said that there wasn't a stat!

think he meant that there wasn't a tank stat, as opposed to the stat in the element.

 

[Pete999]

think he meant that there wasn't a tank stat, as opposed to the stat in the element.

Oh OK sorry OP my mistake.

 

[Timbo]

Shouldn't you have G3 accreditation to work on unvented hot water systems? Or did I waste my time and money?

 

[ETradesmen]

Low and behold, it tripped again.

As I mentioned in my first post I don’t normally go as far as this.

I set the stat temperature as per the drawing shows.

Im done with this particular job but am helping the lovely client as best as I can.

 

[marconi]

I recognise ETradesmen has done his level best and indeed left the client on good terms - good man. Alas the poor woman, (with children?) now has no hot water or at best lukewarm water. Will not a local (Watford?) EF electrician go and give a second opinion?

PS: Any chance of wiring up the mid level E7 element so at least she can warm up half a tank?

 

[snowhead]

Shouldn't you have G3 accreditation to work on unvented hot water systems? Or did I waste my time and money?

Yes you should and that includes energising the immersion heaters or any other heat source and checking full operation including temperature of water at the tap.

 

[marconi]

Ref: # 23: I think I may have worked out what is wrong. I believe the OP may be mistaken about how the electric immersion element is meant to be wired in and controlled.

If I have interpreted correctly what the OP has described, the electric element currently does not have a push on rod thermostat with cutout - the direct heating system. Instead, the element is being controlled by the upper thermostat and cutout which are meant for the indirect system.

If one reads the installation instructions at #23, it describes how to connect up the electric immersion heater with its own stat and cutout, and the indirect stat and cutout to control a boiler. There is a drawing on page 15 and component list which indicates the electric element is meant to have its own stat and cutout. Someone then - the plumber ? - may have discovered the electric element's stat and cutout were defective and co-opted the indirect stat and cut-out instead.

I doubt that the indirect stat and cut-out have the required current rating for the electric element - but may be wrong on this count. Anyway, the indirect stat and cut-out are not designed to control properly and safely the electric element.

What needs to be ordered is the correct stat and cutout for the electric element and it then fitted and wired up as in Fig 7 Page 9. Note Fig 7 shows the upper stat and cutout are not wired to the electric element.

The correct part has this number 95 612 026. See:

Heatrae Sadia - Megaflo Thermostat 11" Rod Type TSE/TSR 95612026 95612599 - Specialists in plumbing & heating spares - https://www.unventedcomponentseurope.com/heatrae-sadia-megaflo-thermostat-11-rod-type-tse-tsr-95612026-95612599.html?utm_source=Google%20Shopping&utm_campaign=Copy%20Unvented%20Components%20Europe&utm_medium=cpc&utm_term=3590&gclid=CjwKCAjwwMn1BRAUEiwAZ_jnEpIuG47ccjQMP8v4i0VP-hIt-MKRx3PP-nXk4_7wkz4vpjQY8pAV6hoCTzEQAvD_BwE

ETTradesmen - hope this helps.

 

[ETradesmen]

N

Ref: # 23: I think I may have worked out what is wrong. I believe the OP may be mistaken about how the electric immersion element is meant to be wired in and controlled.

If I have interpreted correctly what the OP has described, the electric element currently does not have a push on rod thermostat with cutout - the direct heating system. Instead, the element is being controlled by the upper thermostat and cutout which are meant for the indirect system.

If one reads the installation instructions at #23, it describes how to connect up the electric immersion heater with its own stat and cutout, and the indirect stat and cutout to control a boiler. There is a drawing on page 15 and component list which indicates the electric element is meant to have its own stat and cutout. Someone then - the plumber ? - may have discovered the electric element's stat and cutout were defective and co-opted the indirect stat and cut-out instead.

I doubt that the indirect stat and cut-out have the required current rating for the electric element - but may be wrong on this count. Anyway, the indirect stat and cut-out are not designed to control properly and safely the electric element.

What needs to be ordered is the correct stat and cutout for the electric element and it then fitted and wired up as in Fig 7 Page 9. Note Fig 7 shows the upper stat and cutout are not wired to the electric element.

The correct part has this number 95 612 026. See:

Heatrae Sadia - Megaflo Thermostat 11" Rod Type TSE/TSR 95612026 95612599 - Specialists in plumbing & heating spares - https://www.unventedcomponentseurope.com/heatrae-sadia-megaflo-thermostat-11-rod-type-tse-tsr-95612026-95612599.html?utm_source=Google%20Shopping&utm_campaign=Copy%20Unvented%20Components%20Europe&utm_medium=cpc&utm_term=3590&gclid=CjwKCAjwwMn1BRAUEiwAZ_jnEpIuG47ccjQMP8v4i0VP-hIt-MKRx3PP-nXk4_7wkz4vpjQY8pAV6hoCTzEQAvD_BwE

ETTradesmen - hope this helps.

hey, nope it isn’t that stat that works with the tank. I’ve posted a link above to the correct one.

I spent a while on the phone today with technical and they seem to think it’s either the dry pocket that separates the element from the stat or a second return with a pump running 24/7. I don’t really understand the ins and outs of plumbing as I’m an electrician,

I’ve asked her to keep me posted

 

[marconi]

Now I'm flummoxed. Thanks for the feedback. To be clear - no slight on you intended.

To clarify something - you did say this was an all electric home with a separate electric boiler?

I know it is a cheek to ask but might you ask (or suggest to) the lady to post some pictures of her hot water and central heating system on the EF to amuse some locked up leccies?

Regards Marconi

 

[freddo]

Ref: # 23: I think I may have worked out what is wrong. I believe the OP may be mistaken about how the electric immersion element is meant to be wired in and controlled.

It threw me a bit, it looks like the new cylinders have a pair of matching stat/cutout pairs, one for indirect control the other for the immersion. Previous models had a stat/cutout for indirect and a plug on stat/cutout for the immersion.

 

[davesparks]

Ref: # 23: I think I may have worked out what is wrong. I believe the OP may be mistaken about how the electric immersion element is meant to be wired in and controlled.

If I have interpreted correctly what the OP has described, the electric element currently does not have a push on rod thermostat with cutout - the direct heating system. Instead, the element is being controlled by the upper thermostat and cutout which are meant for the indirect system.

If one reads the installation instructions at #23, it describes how to connect up the electric immersion heater with its own stat and cutout, and the indirect stat and cutout to control a boiler. There is a drawing on page 15 and component list which indicates the electric element is meant to have its own stat and cutout. Someone then - the plumber ? - may have discovered the electric element's stat and cutout were defective and co-opted the indirect stat and cut-out instead.

I doubt that the indirect stat and cut-out have the required current rating for the electric element - but may be wrong on this count. Anyway, the indirect stat and cut-out are not designed to control properly and safely the electric element.

What needs to be ordered is the correct stat and cutout for the electric element and it then fitted and wired up as in Fig 7 Page 9. Note Fig 7 shows the upper stat and cutout are not wired to the electric element.

The correct part has this number 95 612 026. See:

Heatrae Sadia - Megaflo Thermostat 11" Rod Type TSE/TSR 95612026 95612599 - Specialists in plumbing & heating spares - https://www.unventedcomponentseurope.com/heatrae-sadia-megaflo-thermostat-11-rod-type-tse-tsr-95612026-95612599.html?utm_source=Google%20Shopping&utm_campaign=Copy%20Unvented%20Components%20Europe&utm_medium=cpc&utm_term=3590&gclid=CjwKCAjwwMn1BRAUEiwAZ_jnEpIuG47ccjQMP8v4i0VP-hIt-MKRx3PP-nXk4_7wkz4vpjQY8pAV6hoCTzEQAvD_BwE

ETTradesmen - hope this helps.

There are different versions of the megaflo, some have the rod thermostat you mention while others have a seperate thermostat unit.

 

[Taylortwocities]

The tank he has Center direct unvented cylinder 150ltr | Wolseley - https://www.wolseley.co.uk/product/centerstore-direct-unvented-cylinder-150-ltr/

Is not a MEGAFLO!!! It’s a Centrestore unvented tank.
Megaflo is the trade name if a company that makes tanks. There are lots of makers.
Like Hoover is the trade name of a company that makes vacuum cleaners.

 

[ETradesmen]

The tank he has Center direct unvented cylinder 150ltr | Wolseley - https://www.wolseley.co.uk/product/centerstore-direct-unvented-cylinder-150-ltr/

Is not a MEGAFLO!!! It’s a Centrestore unvented tank.
Megaflo is the trade name if a company that makes tanks. There are lots of makers.
Like Hoover is the trade name of a company that makes vacuum cleaners.

Correct Taylor, it is a tank made by Heatrae but has a centerstore sticker on it.
Again, going out of way I called Heatrae technical and questioned them and got two possibilities for the cause.

1) dry pocket between the element and stat has failed and both are sitting too close together.

2) if there is a secondary return with a pump to the tank this can also cause nuisance tripping if the pump is running 24/7.

both of the above are out of my comfort level so I’ve passed this information onto the client and wished her luck.