Can Immersion heater be supplied by mains plug?

[Bodgedbuild]

Kettles are water heaters?

Just checked my kettle, it's 3kw! I guess they don't worry because it is not on for long?

 

[AndyPRK]

I used to have a sink/bath switch on my old tank and could get enough water for a quick shower in about 10 minutes. I'll take everybody's advice on not running a mains plug on a 3kw element though and probably plump for a 2.2 or even 1 kw one.
Thanks all.

If you can't get a sensible wattage one (or don't want the trouble/cost in changing it), you could wire the elements in series . That will give you 1.5Kw.
John will worry that the top thermostat will cut them both out too soon. So you could adjust the top stat to be 65°C
And the bottom stat to be 60°C.

Wiring in series is probably over complicating things though.
Worse case you may well end up with only half a tank of hot water, but maybe that would be enough?

 

[EFLImpudence]

Oh dear.

 

[Bodgedbuild]

If you can't get a sensible wattage one (or don't want the trouble/cost in changing it), you could wire the elements in series . That will give you 1.5Kw.
John will worry that the top thermostat will cut them both out too soon. So you could adjust the top stat to be 65°C
And the bottom stat to be 60°C.

Wiring in series is probably over complicating things though.
Worse case you may well end up with only half a tank of hot water, but maybe that would be enough?

I can get a low wattage immersion easy enough. Before going for Airsource heating I was exploring solar options so I explored quite a bit about using waste energy. I might see about getting a UPS for the controller to make things more reliable, then I would only have to use an immersion if the power was off for a length of time, the worst I had was a week but in recent years a day or so has been more common

 

[JohnW2]

If you can't get a sensible wattage one (or don't want the trouble/cost in changing it), you could wire the elements in series . That will give you 1.5Kw. John will worry that the top thermostat will cut them both out too soon. So you could adjust the top stat to be 65°C .... And the bottom stat to be 60°C.

John is not 'worried' about anything, but is merely making some observations about the inevitabilities of physics.

One could, indeed, do as you suggest, and the bottom stat could be set as low as you wanted (provided only that it was set higher than the temp of the incoming cold water) - since, no matter what the setting, both elements would be turned off as soo as th temp of a small amount of water reached 65° (that in the rest of the tank probably still in the 20s, if one was starting from 'cold').

What that arrangement could not ever do is get more than a small amount of water heated and, if that's all one wanted (e.g. for a sink/basin), that would be fine. However, in contrast, a single 1.5kW element at the bottom would result in the entire contents of the cylinder eventually getting up to the temp set by its stat [which is what one would want for a bath, or even lengthy/multiple shower(s) ].

Kind Regards, John.

 

[SUNRAY]

John is not 'worried' about anything, but is merely making some observations about the inevitabilities of physics.

One could, indeed, do as you suggest, and the bottom stat could be set as low as you wanted (provided only that it was set higher than the temp of the incoming cold water) - since, no matter what the setting, both elements would be turned off as soo as th temp of a small amount of water reached 65° (that in the rest of the tank probably still in the 20s, if one was starting from 'cold').

What that arrangement could not ever do is get more than a small amount of water heated and, if that's all one wanted (e.g. for a sink/basin), that would be fine. However, in contrast, a single 1.5kW element at the bottom would result in the entire contents of the cylinder eventually getting up to the temp set by its stat [which is what one would want for a bath, or even lengthy/multiple shower(s) ].

Kind Regards, John.

If the heaters are wired in series and you wish to heat the whole tank then set the top stat to maximum, or even not connect it. and rely on the bottom stat.

 

[AndyPRK]

My initial thought was to set the top stat to 80 c but then I worried about scolding.

 

[JohnW2]

If the heaters are wired in series and you wish to heat the whole tank then set the top stat to maximum, or even not connect it. and rely on the bottom stat.

The water at the top (i.e. the first to be drawn off) could then become dangerously hot.

Indeed, if you "did not connect it" then, were not not for an over-temp cutout (which older immersions don't even have), the water at the top might even boil locally!

Kind Regards, John

 

[SUNRAY]

My initial thought was to set the top stat to 80 c but then I worried about scolding.

If you only have a single heater in the bottomwith its integral stat you have absolutely no idea what the top temp is. One solution could be to fit a destratifacation pump.

 

[SUNRAY]

The water at the top (i.e. the first to be drawn off) could then become dangerously hot.

Indeed, if you "did not connect it" then, were not not for an over-temp cutout (which older immersions don't even have), the water at the top might even boil locally!

Kind Regards, John

would this be that much more significant than a single heater? see #40

 

[JohnW2]

would this be that much more significant than a single heater?

If you had only one heater, no matter what it's location, then if you set the stat to 'maximum' (which is usually at least 80°C), or didn't connect it at all, the same problems/risks would arise - which is why one would be very unwise to set it as high as 80°C (I'm actually surprised they go that high), and extremely unwise not to connect the stat at all!

Kind Regards, John