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grockell

Changing the immersion element within the Calorifier

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Hi,

 

My domestic hot water is lukewarm at best when my immersion heater turned on. I'm guessing the element is in need of changing and I think I understand how to change one (there's plenty of tutorials online which seem relatively straight forward to follow).

 

However, I was wondering if anyone has done this themselves? Any pointers/advice?

 

The only thing that I am unsure about is a gas canister which is connected to the system. I'm guessing this regulates the pressure to and from the hot water tank? See pic 

 

Thanks a lot,

 

George

 

 

IMG_20191202_101117054.jpg

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More likely that the thermostat needs adjusting or replacing if the water gets warmish. Is it the usual domestic arrangement coaxial with the heater or a separate unit?

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What @Onewheeler said. Immersion heaters tend to either work, or not work. Partially working is unlikely. Any idea what power your existing one is? Boat ones are often 1kW, but higher power is possible, if your shore line can take it. You are running it off a shore line, not from batteries aren't you! Most people seem to find 1kW adequate.

The "gas" cylinder is either an expansion vessel, if it is connected to the hot outlet from the calorifier, or an accumulator, if it is on the cold water side, downstream of the water pump.

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The white thing is either an expansion vessel or accumulator depending upon where in the system it is fitted AND what air pressure is inside it. If its connected to the calorifier or hot water system its probably an expansion vessel but one the taps are open and the water pump off it will  do nothing.

 

 

 

SNAP

Edited by Tony Brooks
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Typically immersion heaters either work or don’t work, so I think it would be worth making a few checks before replacing the element. Is there 230v actually on the immersion heater connections? Some designs have a separate thermostat / limit switch so it would be worth checking that that is “on” ie a through connection. Obviously in both cases, take care with mains voltages and in the second case, isolate the supply before checking for continuity.

 

If you do need to change it, the trick is to loosen the immersion with the cylinder full of pressurised water. This helps to stop the rather thin cooper body of the calorifier from twisting/creasing. Only once the thread has turned a bit should you then depressurise the system (pump off, taps open) and unscrew it fully. The expansion vessel will look after itself, don’t worry about it. It’s purpose is just to allow the water to expand into it as it heats up. When you depressurise the system any water in it will come out, but leaving the rubber bladder inside still pressurised.

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Hi all,

 

Thanks for the help. As far as I'm aware, there isn't an external thermostat connected to the wiring. How is see it is - Mains connection via plug --> junction box --> element (see pics).

 

I believe there may be a temperature control / dial within the element box, however I doubt this has been changed since installation.

 

So with the mains turned off, I should test for continuity along the wiring to check for any faults and then with the electricity on check the voltage along the wiring as well. Then if that appears to all be ok, it must be a fault with the actual element.

IMG_20191202_105501487.jpg

IMG_20191202_105425311.jpg

IMG_20191202_104554466 (1).jpg

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Turn off the mains and take that cover off (last photo) and you will find one or even two thermostats inside it, one will have the adjustable dial for temperature. Try turning it up a bit.  If you need to change the thermostat then get the proper spanner and a spare gasket or two.

 

................Dave

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8 minutes ago, dmr said:

Turn off the mains and take that cover off (last photo) and you will find one or even two thermostats inside it, one will have the adjustable dial for temperature. Try turning it up a bit.  If you need to change the thermostat then get the proper spanner and a spare gasket or two.

 

................Dave

Yup, remove the grey cover (disconnect from power first) and take another photo of what’s inside.

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Many years ago I had a similar problem with 'warm' water.

On investigation I found that the Immersion heater element was 'furred' up with lime scale.

A new element sorted the problem and we were back to 'hot' water.

 

Maybe you are in a 'limey' area ?

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7 minutes ago, Alan de Enfield said:

Maybe you are in a 'limey' area ?

Is that an Americanism?

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5 minutes ago, Nightwatch said:

Is that an Americanism?

 

Could be, could be, …. nods as good as a wink to a blind man !!

 

or

 

It could be just 'hard water'.

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30 minutes ago, Alan de Enfield said:

Many years ago I had a similar problem with 'warm' water.

On investigation I found that the Immersion heater element was 'furred' up with lime scale.

A new element sorted the problem and we were back to 'hot' water.

 

Maybe you are in a 'limey' area ?

I was going to suggest that, before I got to the end of the thread. Many years ago, I worked for Remploy who at the time were the biggest supplying manufacturers of heating elements in the UK. The predominant cause of low water temperature was nearly always found to be lime scale build up, or "furring" as it is often known, caused by what our Service Manager always referred to as "Agressive Water!! in other words, a high content if lime in the water. There is no point in trying to remove the limescale, as it will have damaged the element's thin copper cladding.

 

To remove the heater you need a special Immersion Heater spanner, and a lot of elbow grease. Turn the power supply off, remove the dust cover, and disconnect the supply wires, then using as much force as needed unscrew the element from the tank. This can be a challenge with standard old fashioned copper tanks, which can buckle onder the starin of the spanner action, but marine calorifiers are far more robustly built so damage shoud not be an issue. 

 

Spanners can be ontained from places like Screwfix for less than £3.00

 

 

 

                                    image.png.6e600b7ac16e566aecd876dde5f34f90.png

Edited by David Schweizer
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A tubular or box spanner is a better bet, but if using one like David suggests, put two on at once, with the handles opposite each other.  This balances the thrusts so there is only twisting  force on the immersion and enables you to easily apply both hands to the job so applying most force.  From your pictures the existing heater looks well scaled in!

N

 

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Try to loosen it whilst hot and full.

Clout the spanner rather than putting a lot of force on it.

If all else fails, before you wreck the calorifier, saw down both sides down to the gasket and try again. The brass will collapse slightly. I have had to drill them out in the past, just don't touch the tread in the flange ring.

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9 minutes ago, David Schweizer said:

Spanners can be ontained from places like Screwfix for less than £3.00

Do the screwfix ones actually fit marine immersions ?

 

I struggled to find one to fit as the domestic ones were too large.

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28 minutes ago, David Schweizer said:

I was going to suggest that, before I got to the end of the thread. Many years ago, I worked for Remploy who at the time were the biggest supplying manufacturers of heating elements in the UK. The predominant cause of low water temperature was nearly always found to be lime scale build up, or "furring" as it is often known, caused by what our Service Manager always referred to as "Agressive Water!! in other words, a high content if lime in the water. There is no point in trying to remove the limescale, as it will have damaged the element's thin copper cladding.

 

To remove the heater you need a special Immersion Heater spanner, and a lot of elbow grease. Turn the power supply off, remove the dust cover, and disconnect the supply wires, then using as much force as needed unscrew the element from the tank. This can be a challenge with standard old fashioned copper tanks, which can buckle onder the starin of the spanner action, but marine calorifiers are far more robustly built so damage shoud not be an issue. 

 

Spanners can be ontained from places like Screwfix for less than £3.00

 

 

 

                                    image.png.6e600b7ac16e566aecd876dde5f34f90.png

Remploy. Isn't that the company that employs handicapped people David ? I used to sail with one of their organizers in the 1970's,, a chap called Fred, I'm trying to remember his surname.

Edited by bizzard

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Just now, bizzard said:

Remploy. Isn't that the company that employs handicapped people David ? I used to sail with one of their organizers, a chap called Fred, I'm trying to remember his surname.

Yes.

They used to have a factory next door to ours - they were manufacturing / assembling military equipment (rucksacks, webbing etc)

Remploy are country wide and have many different factories.

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Unfortunately Remploy seems to have become a victim of austerity and thermostats aren't what they used to be. The contacts have a habit of arcing and eventually welding themselves together in my experience. 

 

I notice that the OP's Immersion heater is a 27" one. Getting it out of the tank might be a challenge if headroom is limited.

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1 hour ago, grockell said:

Hi all,

 

Thanks for the help. As far as I'm aware, there isn't an external thermostat connected to the wiring. How is see it is - Mains connection via plug --> junction box --> element (see pics).

 

I believe there may be a temperature control / dial within the element box, however I doubt this has been changed since installation.

 

So with the mains turned off, I should test for continuity along the wiring to check for any faults and then with the electricity on check the voltage along the wiring as well. Then if that appears to all be ok, it must be a fault with the actual element.

IMG_20191202_105501487.jpg

IMG_20191202_105425311.jpg

IMG_20191202_104554466 (1).jpg

That looks like its going to be stubborn to undo that element. Make sure its full of water if you do.

12 minutes ago, Alan de Enfield said:

Yes.

They used to have a factory next door to ours - they were manufacturing / assembling military equipment (rucksacks, webbing etc)

Remploy are country wide and have many different factories.

Thank you.

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32 minutes ago, Alan de Enfield said:

Do the screwfix ones actually fit marine immersions ?

 

I struggled to find one to fit as the domestic ones were too large.

I was not aware that there was any difference. AFAIK all immersion heates have a 2 1/4" bsp thread, with a spanner size of 3 3/8" AF. which is sometimes transposed as 85mm, and sometimes 86mm. The one you had must have been a "special"

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6 minutes ago, David Schweizer said:

I was not aware that there was any difference. AFAIK all immersion heates have a 2 1/4" bsp thread, with a spanner size of 3 3/8" AF. which is sometimes transposed as 85mm, and sometimes 86mm. The one you had must have been a "special"

There is a smaller type. 2'' threaded one, I think it is. They fit into certain stainless steel calorifiers and use an O ring, dead easy to undo.  The op's one is the normal domestic size and uses a thin gasket.  I seem to be only able to get the smaller special one from Aquafax and they're more expensive.

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25 minutes ago, bizzard said:

Remploy. Isn't that the company that employs handicapped people David ? I used to sail with one of their organizers in the 1970's,, a chap called Fred, I'm trying to remember his surname.

Remply used to have 83 factories across the UK manufacturing a wide range of products, more tha 90% of the workforce was disabled, many of whom had been injured as a consequence of wartime activity, During the 1980's it gradually rationalized its structure and eventually either sold the factories or closed them. AFAIK only the Furniture division survives as a co-op of ex Rempoly employees.

 

The only Fred I can remember was Fred Croker, who was assistant to the Sales Director.

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4 minutes ago, David Schweizer said:

Remply used to have 83 factories across the UK manufacturing a wide range of products, more tha 90% of the workforce was disabled, many of whom had been injured as a consequence of wartime activity, During the 1980's it gradually rationalized its structure and eventually either sold the factories or closed them. AFAIK only the Furniture division survives as a co-op of ex Rempoly employees.

 

The only Fred I can remember was Fred Croker, who was assistant to the Sales Director.

Croker doesn't ring a bell. His wifes name was Una.  Thanks anyway.

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