Dimplex Quantum RF (or similar) on Single Supply and TOU Tariff

ch_152

Hi all

Read a few threads on this but don't seem to have a clear answer.

My intention was to run a Dimplex Quantum (or similar) off a single supply, replacing my old "dumb" storage heater on an E7 tariff. In such cases there would obviously be no supply at all outside of the night times to the heater.

In this situation, I have concerns about how the Quantum would manage letting the heat out during the day, i.e when it is not switched on. I understand that the normal 24h supply element would feed the fans/convector and the programming so those wouldn't work when the supply isn't live.

Would it essentially just become a better insulated "dumb" NSH? Does anyone have experience with this?


In reality, I'm actually on Octopus Agile and intend on wiring to a smart switch to control on/off times with the consumer unit run permanently live. So wondering if I could just split off the current fused spur to a second located next to it and have one live constantly with the one controlling the heating elements on an in-line timer (e.g relay and contactor)? (maybe a question for an electrician).



Thanks


Chris

Gerry1

https://www.dimplex.co.uk/sites/g/files/emiian551/files/media_import/medias/docus/13/Quantum G12 Installation User Instructions - Issue 2.pdf  (Page 27)

You'll need to check the exact model number but they can be wired from a single 24h supply.  TBH it's a bit of a bodge: it's critically important that you know (i) how to program the switching times and (ii) exactly when your meter switches over.

Don't rely on the web, your DNO, your supplier or your electrician - if they're wrong it could turn out prohibitively expensive if it charges at peak rate.  You need to watch the meter change over and back, and bear in mind there could be a two-hour gap soon after midnight in some areas.  Also check BST/GMT arrangements.

Also consider restricting the ability of the top up heating element to kick in automatically. It'll use day rate and will be expensive.

RedFraggle

You won't be able to run it "dumb" no heat will be released.
You could have it connected to the 24 hr circuit and programme it to charge in your off peak overnight

[Deleted User]

ch_152 said:

Hi all

Read a few threads on this but don't seem to have a clear answer.

My intention was to run a Dimplex Quantum (or similar) off a single supply, replacing my old "dumb" storage heater on an E7 tariff. In such cases there would obviously be no supply at all outside of the night times to the heater.

In this situation, I have concerns about how the Quantum would manage letting the heat out during the day, i.e when it is not switched on. I understand that the normal 24h supply element would feed the fans/convector and the programming so those wouldn't work when the supply isn't live.

Would it essentially just become a better insulated "dumb" NSH? Does anyone have experience with this?


In reality, I'm actually on Octopus Agile and intend on wiring to a smart switch to control on/off times with the consumer unit run permanently live. So wondering if I could just split off the current fused spur to a second located next to it and have one live constantly with the one controlling the heating elements on an in-line timer (e.g relay and contactor)? (maybe a question for an electrician).



Thanks


Chris

Hi Chris - very easy to achieve and something I have done myself, in my case using Elnur HHR storage heaters but the principle is the same. 

However you do it, you need to make sure the existing supply is live 24 hours per day. After that, some heaters will work from this single supply, switching the storage times on and off according to how you program it. Other heaters need two supplies, and having two supplies also gives you the advantage of being able to use some kind of smart timer.

If your heater needs two supplies, or if you choose to go this route soyou can use a smart switch, then it's still very easy (and is what I have had done). The single (24 hour) supply splits at the wall outlet, with one feed going to the heater's unrestricted terminals and the other going to the heater's restricted terminals via a time switch of your choice - smart or otherwise. Definitely a job for electrician IMHO regardless of whether the regs allow you to DIY it or not, because you're dealing with high current wiring that really should be checked after installation and possibly work at the consumer unit end.

You need to think carefully about what kind of timer to use. As well as being appropriately rated for the heater, there's a risk that if you use a wifi switch and/or something that depends on an internet connection that wifi or internet issues stop it switching on or off. And also, speaking from experience, be aware that IFTTT is not really responsive or reliable enough for switching the heaters on and off according to Agile pricing. I'm not on Agile any more as Flux costs about the same (for me!) and is much easier to manage because the switching times are fixed. But when I was, I was using Home Assistant to download the Agile prices for the next day and set a schedule based on them - that way, all the heating control was local and not reliant on an internet connection (and/or everything working at the far end of the connection).

And if doing this at all, be mindful of @Gerry1 advice above - you need to be confident that you've set this correctly and keep an eye on it to make sure nothing changes and you end up using expesnive day rate electricity. It works fine for me but this is an important caveat!

ch_152

Thanks for the replies.

@Gerry1 makes sense. Especially for E7. If I'm on a TOU tariff (e.g octopus agile), then my intention was to use IFTTT to automatically turn on and off at the cheapest periods.

However, as @[Deleted User] points out, maybe this "smart" timing aspiration isn't such a good idea.

And thanks @RedFraggle that is what I'd expected i.e the unit has to have some element of supply for it to actually give out heat. Therefore needs at least one 24-hour supply. 

I think I may go with @[Deleted User] suggestion of splitting the existing 24 hour supply at the wall, having one feed on a smart timer which I can program easily myself (being aware of what @Gerry1 has said in terms of timings), and the other being a 24-hour feed as required by the unit.


Cheers all

tamste

Just make sure if you do a 24hr split and you are on 3 phase supply, that the 24hr split is on the same phase as the TOU heater feed.