Immersion heater help

ROB-123_2

Hi everyone,

I’ve just moved into my first flat and I’m trying to figure out the immersion heater.

The immersion heater has two heat switches- top and bottom.

When I first moved in I switched the top immersion heater on for 2 hours and the water was still cold. So I switched the bottom immersion on as well for a further 3 hours and the water was then piping hot.

My question is: why is there two immersion switches and is it best to use the top or bottom immersion, or both at the same time?

Thanks

[Deleted User]

Hi,

are you on an E7 meter?

If so then one switch will only operate on the cheaper night rate.

ROB-123_2

Nope not on an E7 meter.

Is it best to use the top or bottom immersion, or both at the same time?

Owain_Moneysaver

The bottom element heats the whole cylinder. If you have Economy 7 or similar tariff this should only be run overnight on off-peak electricity.

The top element heats the top of the cylinder for washing-up etc and if you have Economy 7 will be on the more expensive peak tariff.

ChumpusRex

The bottom heater is designed to heat the whole tank. It is meant to be used with E7 electricity. When electricity is cheap, a timer turns the bottom heater on, and you have plenty of hot water for the next day.

The top heater heats only half (or a third) of the tank. This is used if you only want a small amount of hot water, but want it in a hurry. The water should be piping hot in about 30-45 minutes.

You would normally use the top heater to provide an emergency top-up if you run out of hot water heated by the bottom heater. This would usually be during the day (on full price electricity).

If you really did leave the top heater on for 2 hours and the water was still cold, then it sounds as if the heater is broken.

If you don't have economy 7 electricity, it really doesn't matter which heater you use. However, the top heater likely won't heat enough water for a bath.

Richie-from-the-Boro

ROB-123 wrote: »

Hi everyone,

I’ve just moved into my first flat and I’m trying to figure out the immersion heater.

The immersion heater has two heat switches- top and bottom.

When I first moved in I switched the top immersion heater on for 2 hours and the water was still cold. So I switched the bottom immersion on as well for a further 3 hours and the water was then piping hot.

My question is: why is there two immersion switches and is it best to use the top or bottom immersion, or both at the same time?

Thanks

immersion heater has two heat switches- top and bottom

The one you switched on during the day is the day [expensive] rate, the other one should be the night [cheap] rate and may still work depending on the tariff you are on. start by telling the group what kind of space heating is in the flat and what electricity tariff are you on ? A photograph of the immersion element and the switches would help.

dogshome

It seems that the Immersion heater for the top of the tank has failed -( If this flat is rented it's up to the landlord to replace it )

Changing the heater is not a difficult job if you have reasonable DIY skills - Buy the correct spanner, they are cheap, to unscrew the heater from the top of the tank - Cut off the water supply from the static water tank that supplies the hot water tank and drain down it's contents by running the hot water taps.

Having disconnected the wiring so you can get the spanner onto the head of the immersion heater, do not heave on the spanner to unscrew the heater as this is likely to distort the tank - Lightly tap the end of the spanner repeatedly with a hammer, this will take a while, but the repeated vibration will break the seal between the Heater and the tank without haming the tank

Owain_Moneysaver

If it's an unvented hot water cylinder (no cold water tank in the loft) then changing the immersion heater must be done by a plumber with an Unvented Hot Water qualification.

footyguy

ROB-123 wrote: »

Hi everyone,

I’ve just moved into my first flat and I’m trying to figure out the immersion heater.

The immersion heater has two heat switches- top and bottom.

When I first moved in I switched the top immersion heater on for 2 hours and the water was still cold. So I switched the bottom immersion on as well for a further 3 hours and the water was then piping hot.

My question is: why is there two immersion switches and is it best to use the top or bottom immersion, or both at the same time?

Thanks

Hot water rises, so any water below the heater will not be heated.

The top heater therefore only heats a small amount of water, and is designed to be used as a boost should you run out of hot water. As it only heats a small amount of water (and is the same size heater) it will heat that water quicker.

The lower heater heats all the water above it (so essentially almost the whole tank full). If you have E7, then this heater should be used during the low rate supply period to heat the whole tank full using the low rate electricity.
Hopefully this weill serve your needs for the entire day (although that will depend on how much you use of course).

As you do not have the possibility of low rate electricity (E7), then use the heaters to heat the water you expect to use.
e.g. the top heater for hand washing etc, and the lower heater for larger uses such as a bath.

It sounds like bad news if the upper heater has failed to heat the water at all as this sounds like it is defective (as dogshome suggests).

If you rent the property, then contact the landlord/agent and ask that it is repaired as soon as possible (obviously at no additional cost to you)

Richie-from-the-Boro

In almost 40 years of E7 in two different dwellings I have (1) never used the 'top up' element ever, never used (2) the 'damper' boost on a heater ever and (3) never switched off the 365 whole year water heating. This because none of the three make economic sense to me. E7 heating of water or space is about comfort & convenience as much as it is about °F or °C, the quantity of stored energy in the bricks of space heaters or water @ is what really counts. Once I have sufficient cheap energy stored the stat switch off and the need for the expensive top up space or water heating never arises, the partL insulated cylinder of itself has an acceptably low thermal loss transfer rate never to need to be turned off other than holiday for safety purposes, and in any case there's no real time loss of money as the 60% cheaper energy goes into the dwelling anyway.