Immersion Heater Advice Please

SnakeDoctor_2

I have economy 7 electricity and gas central heating. I was using the immersion heater to heat the tap water during the night then the gas heating to boost it during the day. I've just had solar heating installed with an iBoost+ that heats the water when solar electricity is being exported. I wanted to stop using gas on all but a dull day.
What I'm finding is that I'm not getting much hot water (hot enough) and I'm starting to think that maybe the immersion heater is a short one and only heating the top of the well insulated tank. In the past I suspect that the gas was heating from the bottom of the tank.

Does this make sense? And is it possible to replace the short immersion heater with a longer one so that it's heating all of the tank?

Thank you

Smiley_Dan

You'll certainly get stratification, but all the water above the coil should be heated.

How big is the tank (ideally, what is the volume?) and where is the coil installed.

Ours is only 1/3 of the way down of a 210l tank and we get plenty of hot water.

Is the iBoost correctly installed, can you see a readout of it working? Is the thermostat tripping early?

matelodave

As said, what size is your tank and where is the immersion heater situated (in the top or at the side). Generally it will only heat water above it so to heat the whole tank it needs to be at the bottom.


You may be able to fit a longer heater if it's top mounted but there's a fair chance that it will foul the central heating coils within the tank

SnakeDoctor_2

Thanks guys.
It's a 140 litre tank, the immersion goes in at the top and one gas heating pipes go in half way down and the other very near to the bottom. I've just taken the immersion thermostat out and it's only 7 inches long. Is that another indication that the immersion is short too?

SnakeDoctor_2

There's nothing on the iBoost to be wrongly installed - 3 wires in, 3 wires out; just like the time switch that it replaced. The display tells me when it turns the power to the immersion on and that corresponds with the immersion making that heating noise.

matelodave

SnakeDoctor wrote: »

Thanks guys.
It's a 140 litre tank, the immersion goes in at the top and one gas heating pipes go in half way down and the other very near to the bottom. I've just taken the immersion thermostat out and it's only 7 inches long. Is that another indication that the immersion is short too?

Not necessarily although likely. The thermostat will control the temperature however long the heating element is - you'd need to take out the element to check it's length. But as I said, the central heating coil inside the tank will be as high as the top connection so you might find that a longer element will foul it unless the thermostat boss is near the centre of the top of the tank and nearly vertical.


Here's a selection from Screwfix http://www.screwfix.com/p/titanium-immersion-heater-element-27/75262

SnakeDoctor_2

Thank you.