Quantum Dimplex Night Storage Heater Won't Charge at Max Rate

That’s what tends to happen if you’re in the dark without a compass! It would really help to see the photos I asked for, to eliminate at least some of the guesswork. 

Sorry… what photos…?

It’s not always easy to keep track! This is what I posted a couple of days ago:

Thanks Firedog, but I think you may be over-thinking this!  I do have a pretty in depth understanding of my smart meter (it’s a Liberty 116), how it is wired and to which circuits and when those circuits are active under the Octopus tariff (although I did have to figure all this out on my own - no info was provided by either Octopus or the installer whatsoever).

Anyway, in the meantime Dimplex have finally provided an intelligent and useful response:

“Good morning

Thank you for your further contact

I have be asked to look into your case and provide feedback from a product perspective. Having reviewed your emails, I can advise:

Elements

As you are aware the Quantum storage heaters contain 3 electric heating elements, all 3 of which are used when the unit charges during off-peak hours. However, the lower of the 3 element can also be utilised as a boost element during peak periods if required.

Regretfully, not every component in our products produce a fault code upon failure. Should an element fail within a Quantum, the unit will continue to receive readings from the various temperature sensors and log the data, but it would not trigger any error code.

Having reviewed the images you previously provided of the 7 day history, whilst the heater does not appear to be calculating its maximum capacity of charge, I would expect the core temperature to be nearing its limit of 110oC, whereas it only appears to be reaching around 70oC. This would generally suggest that the unit is operating at only 2/3rds of its total output, and that an element has possibly failed. Obviously, the only way to really confirm this is for an engineer/electrician to electrically test the elements.

Service call

If an element is faulty, it will require replacement which we would usually send and engineer to confirm and replace. However, given your location I will need to discuss the matter further with our scheduling team to see how best to proceed with this matter.

Quantum output

In answer to your question regarding the Quantum’s output, as I previously advise the Quantum heaters have 3 elements all of which are used to heat the core during an over night charge, i.e. 3x 340W = 1,020W. If only 680W is being used per complete hour, it would suggest again that 1 element was not operating. If all 3 elements were operation and the unit took a charge for the complete 7hrs it would meet it’s maximum capacity, 1020W x 7hrs = 7.14kWh.

As advised above, the issue you are experiencing suggests that an element may not be operating, and requires further investigation or replacement. I will discuss the matter further with our scheduling team to determine the best cause of action.

In the meantime, thank you for your patience

Carl”

So, it looks like a defective element - which is disappointing given that the heater is only 3 years old but at least it’s progress and I can fix it in time for winter.
THanks to all for their input.  MW

​@martinwinlow I’m happy to hear that Dimplex are starting to get to the bottom of this. Hopefully their Scheduling team can sort something out for you ASAP. Please keep us updated as to how this goes.

That’s quite possible, but if I am it stems largely from lack of information!  

It’s more than a fortnight ago that I wrote in my first response to you that “We know that ‘insufficient charge’ can with older NSHs indicate that a thermostat or one or more of the heating elements have failed; there should be on-board diagnostics to reveal that sort of fault.” It’s sad to learn that the on-board diagnostics don’t stretch to telling you when something has broken!
  

Are you on Fair Isle or Rockall or somewhere? 
  

I don’t remember ever hearing from a customer with a Secure Liberty 116 meter, and I’m not at all surprised that a domestic supplier’s staff aren’t particularly familiar with it - it’s much more complex than the ones we normally deal with. Knowing this goes a long way to explaining why I was confused about your offpeak feed management.