Two hot water cylinders - probably daft question

[bitstreams]

I have moved in to a house that has oil fired central heating. One side of the house was used as a granny annexe and I think this might be why I have this situation.
The oil boiler is in a shed attached to the back of the house and next to it is an 'unvented indirect cylinder'. This has a power switch next to it which is generally switched off and I am assuming that this is both the hot water tank that is heated by the oil boiler, but also an immersion heater if I need it to be.

In a bathroom cupboard on the other side of the house is a water cylinder that is, I think, a standard immersion heater and is also generally switched off.

My probably daft question is are these both immersions and are they both on the same system, i.e. when the oil boiler is heating up water is it storing it in both of these tanks? When we had boiler problems a few weeks ago I switched on the 2nd one (the one that looks like a standard immersion) and I think I got hot water everywhere.

 

[DP]

Immersion heater is there for that very reason when the boiler plays up.

Good idea to fire up the immersion heater every 3-4 months or so to ensure it is functioning. Often see these are waterlogged and split

 

[bitstreams]

Immersion heater is there for that very reason when the boiler plays up.

Good idea to fire up the immersion heater every 3-4 months or so to ensure it is functioning. Often see these are waterlogged and split

But are they both immersions? and does the boiler fill them both up?

 

[flameport]

But are they both immersions?

Impossible to know from the pictures provided.
If the green one has an immersion heater it will either be in the side or the top, with a flex from that to a switch or timer on the wall.

They may both be heated from the boiler - switch it on and see if the pipes to each cylinder get hot or not.
Or they could be entirely separate items.

 

[DP]

But are they both immersions? and does the boiler fill them both up?

Immersion heater for UV is behind the plastic cube like cover on the cylinder
On the vented cylinder immersion easily seen.

Both will have a coil through which heated boiler water flows to heat the cylinder, much faster than the immersion can

 

[Madrab]

The top one, being an indirect cylinder would normally be heated by the CH, if it is connected to it. The bottom one, we can't see if it is indirect or direct, full pic of the label would help. Again though, if indirect, it would still need to be actually connected to the Central Heating to be warmed by the boiler. The boiler doesn't fill them up, it only heats them up.

Both would normally come with immersion elements as a backup if the heating failed.