Dimplex Quantum qm70

[Ian845]

Hi everyone,
I have old storage heaters in my house that are all properly connected to off peak E7 supply via there own fuse box.
As the heaters are old, arnt cost effective and have little control, i was looking into changing over to the dimplex quantum range.
I have noticed the quantum range has an off peak connection and a peak connection.
Can the peak connection be connected to a 13A plug and plugged into a wall socket?
The off peak isnt a problem because its already set up.
If the peak connection cant be plugged in to the wall then I guess new spurs will have to be wired into every room? (Which I dont really want to have to get done).
If thats the case can anyone recommend a storage heater that has the control and efficiency of the quantum but with just the off peak connection.
Appriciate you reading this and any help / responses

 

[stem]

The 'peak' connection is there to operate an internal fan to boost the heat output during the day. It can also operate a supplementary electric heater to provide additional heat if there is not enough stored heat available (This function can be disabled in the settings if preferred)

I have seen the permanent 240V supply plugged in. However, the Quantum instructions do say otherwise.

Generally an FCU is fitted instead of a socket, which isn't any more difficult to do. However, if the permanent supply isn't present for each heater, then yes it would have to be installed.

There is a possible alternative. If your electricity supply is one where during the E7 hours the whole property switches over to the 'off peak' rate, it is possible to use these heaters with only a single permanent supply connected to the heater. To utilise this, the existing storage heating 'fuse box' would need to be changed over to being a permanent supply (instead of an E7 supply) and then the 'off peak' times programmed into each storage heater so that they only store heat during the 'off peak' hours. The danger here is that if you get the timings wrong, you would be charged for electricity at the full rate. There would be some electrical work to change over the E7 'fuse box' but it would be less than running new mains supplies to each of the heaters. Also, if there is any electric water heating connected to the same E7 supply as the heaters that would need to be modified also.

Regarding efficiency. All electric heaters that have resistive heating elements are 100% efficient. So when you use 1kW of electricity, then you will get 1kW of heat. Newer heaters have better insulation and controls to prevent heat being emitted when it's not required, so it's more about controlling the heat more effectively. So, unless you find that your home is presently overheated new heaters won't make much of a change to your electricity consumption.

 

[Ian845]

Hi Stem,
Thanks for your reply,
Im not sure of the setup, there are 2 seperate fuse boards it says off peak CU and 24 hour CU, all the heaters are on the off peak CU and plugs etc on the 24 hour.
If the connection was put into the original spur the heaters are connected to, wouldnt this mean the fan etc would only come on at off peak times. At the moment the heater switches are permanently on and the heaters only charge/take electricity during off peak.
I have noticed the plug sockets upstairs and down are on seperate fuses in the 24 hour CU.

 

[Ian845]

Oh I forgot to add,
The heaters at the moment have zero control. On the lowest output setting the bedroom heater blasts out the heat its so hot we have to open the window. If I lower the input to 2-3 it runs out and is freezing when we goto bed.
The front room is on 6 input constantly but bearly gives out heat. I couldnt touch the bedroom 1 when hot but can hold my hand on the front room 1 as its luke warm, and its on max setting! They just have zero control no matter how you set them. Its either low input setting and freeze at night or higher input and literally boil in the early hours, cant win

 

[JohnD]

If you are out of the house all day, then storage heaters are probably unsuitable for you.

Retired people, and households with babies and small children, like them because they often get up and go to bed early, and are at home throughout the day.

For a bedroom, you might consider a plug-in oil-filled radiator or similar. You can turn it on before bedtime and most of the night it will be running on offpeak electricity. With a thermostat the room will not get too hot.

 

[JohnD]

The front room is on 6 input constantly but barely gives out heat.

might be a fault in the controls, or a failed element.

The components in these are actually very simple, it may be possible to have it repaired by a local qualified electrician

 

[stem]

there are 2 seperate fuse boards it says off peak CU and 24 hour CU, all the heaters are on the off peak CU and plugs etc on the 24 hour.

Normally the Off Peak CU is automatically switched 'on' only when the cheaper Off Peak electricity is available so the existing heaters are wired directly to it. The Peak CU will be energised permanently and normally uses whatever is the going rate at the time, so it will switch between the on & off peak tariffs. This is the kind of installation I was referring to and most are now like this.

Some older installations (and it's a long time since I have seen one) have two completely separate electricity meters, which means that the Peak Rate is permanently Peak, and doesn't switch over to the cheaper rate at any time. This type wouldn't be suitable for what I suggested.

If the connection was put into the original spur the heaters are connected to, wouldnt this mean the fan etc would only come on at off peak times. At the moment the heater switches are permanently on and the heaters only charge/take electricity during off peak.

Assuming that you have the first system I described above, where the Peak CU switches between tariffs, my suggestion was to change the Off Peak CU so that it was wired into the same supply as the Peak CU. This would mean that all of the heaters would now only receive a single permanent electricity supply via the existing connection. This would be able to run the boost fan during the day. But the Heaters themselves can then be programmed so that a charge of heat only occurs during the time when the supply has switched over to the cheaper rate. As I mentioned previously you would have to be careful to make sure that the programmed 'charge' times match the Off Peak supply times otherwise you could be charging the heaters at Peak Rate inadvertently.

Personally I wouldn't do it because of the faff of having to set the charge times at each heater and the possibility of a mismatch in relation to the Off peak supply times (especially when the clocks go forward / backward) but you did ask for a way to use the heaters without running "new spurs to each room" and this would allow you to do that.

You would still have to engage a sparkie to change the Off Peak CU supply over but it is only a half day job.

 

[Diver Fred]

The Dimplex Quantum NSH operates differently to earlier generations of NSH.
Early Night Storage Heaters you control how much heat they store so also how much energy they consume.
Quantum NSH Do Not have any (manual) control on how much energy they consume overnight - assume its full power all the time. The hot core is (supposedly) better insulated and the heat is dispersed to the room by a fan - so it's a Fan Heater but the heat is purchased at a cheap rate. That part is controllable, including to the hours it is heating a room.
Do note the bigger ones (maybe all) also have a fan element in the output side of the stored heat so if the blocks cannot provide sufficient heat the fan element will assist at the day rate of electricity!
So if NSH are the only form of heating in the room/property they are probably cost effective. If they are used as background heat to a second, probably cheaper heat source then I'd say it's a close call.

May I suggest that you do some investigation of the existing heaters; the one which is excessively hot the input control is Not working as it should, the input temp is controlled normally by a Bi-Metal strip with contacts on, make sure that is flexing and isn't shorted out (I had tenants who thought the one in heater was faulty 'cause it broke the circuit when hot). The one not getting up to temperature does sound like one of more elements have failed. It's cover off and check each element in turn and make sure the screws are tight. There is 2, 3 or 4 elements in each heater.

Let us know how you get on.

 

[Ian845]

Thanks everyone for all your comments, all valid points and good ideas.
John D the house doesnt have a gas supply and it cant be installed, i guess at the time of build storage heaters were the only valid option? Its a good idea having an oil filled rad, one that I was going to go with however, off peak elecricity is from 1am and we go to bed before this. If I ran it to warm up the room before bed it would be using peak which is alot more expensive than normal on E7 tariff.
Stem, I agree to have to program the would be a pain but something I dont mind doing if it solved the problem of having to have new spurs wired in for the peak connection. I am now thinking after reading wgt52's comments maybe just changing the 2 bedroom one and getting the others looked over. I like the fact with the quantum you can keep a room to a set temp.
I agree though wgt52 there is definately a fault with the ones I have but wasnt to sure exactly how they moderated the heat.
Thanks for all your help and advise. I will let you know how I get on.

 

[flameport]

f the peak connection cant be plugged in to the wall then I guess new spurs will have to be wired into every room? (Which I dont really want to have to get done).

That is the only option. The 24 hour supply isn't just for a heating boost, it's required for the electronic controls. Without it, the heater will not work at all.

If thats the case can anyone recommend a storage heater that has the control and efficiency of the quantum but with just the off peak connection.

No such thing any more - all storage heaters sold after January 2018 require dual supplies.
Search for 'lot 20' for more details.

 

[stem]

Stem, I agree to have to program the would be a pain but something I dont mind doing if it solved the problem of having to have new spurs wired in for the peak connection. I am now thinking after reading wgt52's comments maybe just changing the 2 bedroom one and getting the others looked over. I like the fact with the quantum you can keep a room to a set temp.

If you did go with my suggestion of changing the 'Off Peak' consumer unit to provide a permanent supply to the heaters and then using the Quantum's internal programmer to set the 'Off Peak' charge time. You would have to change all of the heaters over to Quantum's because the older heaters won't have the facility to program their charging times manually, meaning they would be on charge permanently 24/7.

 

[phatboy]

As much as the installation manual says the peak side must be connected via an FCU, I would think this can be ignored as it's nonsense.

The Quantums are MUCH better at retaining heat, and the heater barely feels warm at all unless it's an extremely cold period and so it's completely charged.

We have them throughout the house, replacing some old Dimplex XL series storage heaters, and much prefer them.

No controls need changing like the daily opening and closing of flaps on the old ones - just set to the desired temperature and leave it for the entire winter.

 

[Ian845]

Thanks for your reply phat boy. Out of interest how are the connections on your quantums installed

 

[phatboy]

Thanks for your reply phat boy. Out of interest how are the connections on your quantums installed

Peak is via an FCU, and off-peak is via a 20amp switch, back to a breaker in the off-peak board. This is because we refurbished the whole house including a re-wire.

 

[EFLImpudence]

Once again the manufacturer's instructions are found to be "less than ideal" but some people say they must be obeyed.

That is apparently except the part about "must be carried out by a suitably qualified or trained electrician"; this is always ignored.

There is no difference between a 'plug' and a 'fused connection unit' (which is not a 'spur').

What is an 'isolated switch'?