Megaflow daytime heating failure

[patrick77]

Hi,

We just bought a flat with a Megaflow boiler, this is connected to 2 separate power supplies, as we have a 7 meter (cheaper electricity overnight).
The Megaflow fills with hot water overnight and works all fine in that respect.
But the hot water runs out very quickly and the Megaflow does not supply us with any more hot water during the rest of the day, despite it being connected to the daytime electricity supply as well.
There is no leaking anywhere that would hint to losses of pressure in the tank and it looks generally in a good state (plus it works perfectly overnight).

Would anyone have an idea as why our Megalfow does not supply hot water with the daytime electricity supply?
(Before you ask, yes the daytime electricity plug is switched on  )
Happy to hear any suggestion before contacting a professional.

Many thanks in advance,
Patrick

 

[gas112]

Twin immersion heaters ? one has gone kaput possibly depending how its wired

 

[patrick77]

Thanks gas112, I have now googled "twin immersion heater" and feel a bit wiser now.
I will have a look if there is any other possible wiring/electrical issue, if not I will call a plumber to replace the immersion heater.
Cheers.

 

[Agile]

You have an el;ectrically heated unvented cylinder and not a boiler.

In many cases its better to replace both immersions if the lower one has failed which sounds like the case in your fault.

People don't seem to realise that immersion heaters have a rather limited life if used 24/7

The failure could also be caused be something else.

Tony

 

[patrick77]

Hi Agile,
thanks for the advice.
I am not a technician of any kind, but after reading a bit online it looks like the bottom induction heater is the one going on cheap electricity (the bit that works) and the top heater is the "boost", which should work during daytime but does not.
If that is confirmed by the plumber I do not see the need to change the bottom induction heater.
Let me know if I misunderstood.
Thanks.

 

[Agile]

It sounds to me as if the upper one may have failed!

That would give you a full cylinder of hot water in the morning if it is working.

The day boost one indeed is the top one but that only heats the top half of the tank.

That would run out quicker but should reheat in an hour or two.

With normal use the lower one is in use for longer and is most likely to fail. Changing it is usually more involved as the whole cylinder has to be drained! There should be a drain cock but they are poorly made and often the washer sticks.

Tony

 

[patrick77]

Thanks for confirming my suspicion.
(I was looking for the "thanks" button, but apparently it has disappeared)