So how much power does an oil filled radiator actually use.

[whisky-dave]

As some might have read we've been supplied with a number of oil filled radaitors

So I unpacked them and installed them, one by one.

In an attempted to trip our 32 amp circuit braker I would have thought that 5 would have done it, but they didn't.

On switch on they started at about 1.6KW (using an old maplin power meter) I left them fully on, that's the highest setting .

The lab voltage dropped from the 220V to about 202V so that accounts for it I guess.

But what realy suprised me was the power consumption of a radiator when it was full on, anyone care to guess what it was.

Voltage 202

[Andy Burns]

(5 x 2kW / 240V) ~ 42A, a typical type B 32 amp breaker will supply north of 45 amps for at least 2.7 hours, possibly for "ever".

[Tim Watts]

Also, did the radiator cycle a lot on its thermostat?

Many oil rads are incapable of losing the heat to the air at a rate that matches the element rating - so they cycle on and off.

A shit B&Q rad would cycle at about 50%.

DeLonghi Ventos that I have can more or less maintain full output power due to a superior fin and air path design.

[whisky-dave]

That's what I wasn't sure about we had them on for about 2 hours then a student reported that his soldering station had just switched off and wouldn't come back on again. So know I know how far I can push it ;-)

We had another 7 1.5KW radiators delievered yesterday.

cheers interesting.

[whisky-dave]

That's what confused me, I assumed that if the LEDs were on with the thermostate set to maxium it'd it would use about 2KW, but I found that it was just 705W.

If I reduced the thermostat knob then the LR+EDs would go off and the consumption dropped to 0w as expected. After letting it cool and turning the thermostat back to full, the LEDs came back on and 1.7KW .

I guess this cycle is 1.7KW and 700W , I guess I'm used to cycles going fron zero to full.

I have a DeLonghi at home maybe I'll test that too.

[Tim Watts]

700W suggests you had the selector switch on half power (one element out of two).

It would cycle on and off, not through half power...

[whisky-dave]

Might suggest it but it's not the cae.

fort eh last 2 hours it;s been full on at 705 watts. If I switch of teh I rocker it;s LED goes out the other II LED remains on and the power drops to 0W, a few mins later I hear a click the same LEDs on and off but the power goes to 1045W. Switching the I back on power 1734W Switch II off 702W

So you obviously have this wrong.

but that's not the case it appears as though when fully on for a lenght of time II elements are switched out and the I left on, unless you manually switch it off.

[Scott]

Why do people start sentences with conjunctions?

[Caecilius]

Is that a B32 MCB? If so, it will trip according to the "B" trip curve, which means that instantanious trip needs at least 3 x rated current.

At 220v, 5 x 1.6Kw heaters will draw at most about 36A, which will essentially never trip a B32 MCB.

See the trip curves here:

[ARW]

1.164kW

[ARW]

Don't fall for the mixup with B, C and D types.

Let's assume that all 5 heaters are not switched on at exactly the same time then B rating is irrelevant.

The B rating covers the inrush current not the stabilised load.

[pamela]

radiator-

36A is a lot. Wouldn't that melt the insulation on the wires?

[pamela]

It's alright to do so......

[T i m]

In addition to what has been mentioned elsewhere, the link suggests you have a 3 level (switchable) heater, where one element is ~700W and the other 2000-700 = ~1300W.

So, you have choice of output powers of (nominally) 700, 1300 and

2000W.

The thermostat *should* function on all / any settings (so you should measure 700, 1200 or 2000W or nothing).

The 'overtemp' switch should also work on all / any and that may or may not cut in (open) before the thermostat does, depending on what wattage you are using (input energy > output load).

The 'on' indicator may or may not indicate it is heating or that it is just on (depending where it is in the circuit).

Anything else would suggest that it's either wired incorrectly, or is supposed to work like that (instructions)?

Cheers, T i m

[Tim Watts]

No. The current carrying capacity of a cable is determined by (mostly) how hot it gets.

A ring final circuit is designed to run forever at 32A with a max of 20A in any part of the cabling.

This is based on PVC cable having a max operating temp of 70C.

In practise:

1) A few degrees over won't do much;

2) There's loads of padding built into the numbers;

3) If you overload a cable to say twice its rating and the MCB takes say 15-20 minutes to trip, the cable has not instantlo y heated up to beyond 70C - it's gradually overheating and the Type B curve is designed to reflect that.

[harry]

Drivel. They dissipate more heat in a cold room.(ie,are constantly on.) As the room warms up, then they dissipate less. The heating element is sized for the cold room

[harry]

The amount of time they remain "on" depends on the ambient temperature. ie, in a cold room, they are on for longer the heat dissipates faster.

[Brian Gaff]

I like oil filled radiators. I have one in a room to help clothes dry its less thatn a kw and seems very efficient if the thermostat is set sensibly. Its an old Belling. Only issue is that the front plastic cover and know are cracking presumably due to age heat and vaccuum cleaner abuse! Brian

[whisky-dave]

Yes that seems reasonable.

So if a heater is left on in the III position and the thermostate fully clockwise in it's maxium position what electrical power will the heater use and how much will it cost to leave it on from 9-5.

if I have 5 of these and two 1.5KW versions set to the same settings how much will this cost to run from 9-5 ?

That's the sort of things I'm curious about as at 9am the temerature was 14C it is now 12 midday and teh temerature is 15C (so still below the recommened 16C as stated in the 1992 factories act section 7.

Yes I do pretty much get those results. I aslo tested the impedence which seems to be 25 ohms to 65 ohms from memory as I can't find the paper I wrote it down on a few days ago.

Yes I know, so with both lights on what power should the heater be running at.

Well the instuctions are on the site, but are not the same as the ones delivered but look the same with very similar specs and look pretty much the same.

[whisky-dave]

that 5 would have done it, but they didn't.

or it I guess.

n it was full on, anyone care to guess what it was.

Yes we thopught of that, left them all off for an hour to cool then there w as 3 of us 5 rads and we had a countdown we all turned them on full at the same time, and it didn't trip, a couple of hours later it did but there w as also a soldering station that;d beeen switched on but it was less than a few 100w .