insulating immersion heater

mrbrown

hi,
I have Economy 7 heating and an immersion tank. Im looking at ways that I can keep the hot water hotter for longer. Ive bought some insulation material, but the thermostat on the top of the cylinder reads "Do not cover".

The diagram on the insulating packaging I bought shows the cylinder being completely covered. Im aware that the top of the cylinder needs to be covered the most because this is where the majority of the heat is going to escape. Is it a safety risk if I cover the thermostat head? Should I pack as much insulation around the tank as possible?
Thanks

ormus

you should follow the makers instructions. do not cover the thermostat.
by all means cover everything else. the thicker the better.

27col

The diagram on the packaging probably shows a cylinder without an immersion heater. If the immersion heater says do not cover, then do not cover. To quote a Meerkat " simples".

mrbrown

Thanks.
The manufactureres instructions are minimal to say the least!
I can see a white wire coming from the thermostat - I guess this is the power cable and so shouldnt be covered. I can also see green/white wires (earth) coming from somwhere and being attached to 3 copper pipes. Theres some bare wire exposed from these. Is it OK to cover these and is the exposed wire a safety/fire hazard?

anotherbaldrick

mrbrown wrote: »

Thanks.
The manufactureres instructions are minimal to say the least!
I can see a white wire coming from the thermostat - I guess this is the power cable and so shouldnt be covered. I can also see green/white wires (earth) coming from somwhere and being attached to 3 copper pipes. Theres some bare wire exposed from these. Is it OK to cover these and is the exposed wire a safety/fire hazard?

The exposed bare earth wires are not a safety/fire hazard,I would not recommend burying them or other cables below the insulation . In particular the clips bonding the earth wires to the copper pipes should be left free of insulation so that anyone inspecting the electrical system can observe that the bonding is in place and intact.

mrbrown

Ive decided that because I use such little hot water, Ill just boil a kettle in the morning and do my washing up then (Im on a budget!). Then when I do have a shower Ill turn the immersion on for 30 minutes before 7am (while its running on cheap electricity). Boiling a kettle each morning must be a lot cheaper than having the immersion on for 30 minutes right?

Viper_7

I need to ask... but are you sure the cylinder is not already insulated??? It's very peculiar to have Economy 7 with an uninsulated cylinder...

That's the entire point...heat up over night and then use the water through the day. Majority of E7 cylinders are double insulated.

If not.. an it's just a bare copper cylinder, then by all means insulate the cylinder but leave wiring and the actual immersion heater uncovered.

Vipes

Peartree

I think confusion might arise with the language the experts are using - dumb people like me often consider 'immersion heater' to be a synonym fo 'entire copper cylinder and encoutrements arrangement'!

I've got a copper cylinder with an immersion heater (I now realise) and it has many, many inches of the padded insulation 'coats' on it - only constricted by the need to close the door of the cupboard. However, these are drawn back in the area where the wires are going into the thermostat (around the circular bit on the top?) due to a label that says 'do not cover' - albeit not an offical label simply written and stuck on by my Dad who replaced my broken thermostat/immersion heater??. With the segmented padded coats you can buy, it is easy to leave that gap and I don't, honestly, think it makes a great deal of difference to the overall heat retention of the tank.

In summary all I can add is insulate to your heart's content with many of the coats but don't cover that little area where all the wires go in or a "Bad Thing Will Happen" that you probably won't understand but will need to pay for (if you don't have a Plumbing Dad available).

mrbrown

Viper_7: Yes, its just a bare copper cylinder. I hear different things from different people - some say leave it on all night, others say heat it for just an hour and it should last most of the day. The thing is is that I use such little hot water because Im at work all day. Each day I spend 5 minutes using it to wash the dishes - and thats it! Im going to start heating a kettle in the morning and using that instead, and then when I have a shower turn the immersion on manually.

Peartree: It is hard to believe that 180mm of foam can make much difference the the heat retention isnt? Lucky you for having a Plumber Dad!:D

macman

If it's properly insulated, it should retain its heat for hours-with an immersion you should only need a couple of hours in the early morning and maybe in the evening, depending on usage.
Remember though that if you boost it outside the E7 cheap rate hours then you are paying a considerable premium to do so.
A tank jacket will make a huge difference to the heat retention (copper is a good conductor of heat), so get it done as a priority-you'll get the minimal investment back in weeks.