I have just completed the testing of my De’Longhi Dragon 4 oil filled heater and here are the results………
Dragon 4 power settings : 900W/1100W/2000W
The test was carried out at the 2000W setting
Ambient temperature for the test was : 19.6C
Time. Power draw. Top of oil chamber. Inside Chimney (air). Outside surface of chimney
10min. 1950W. 110C. - -
15Min. 1945W. 130C. 98C. -
20Min. 1920W. 148C. 108C. -
25Min. 1940W. 160C. 108C. -
30Min. 1930W. 169C. 107C. -
35Min. 1937W. 173C. 108C. -
40Min. 1930W. 176C. 108C. 94C
45Min. 1922W. 178C. 107C. 94C
So the test was performed using two known accurate thermocouple thermometers from ETI and associated thermocouple probes. One rested on top of the oil chamber and the other was an air probe placed in one of the chimneys. A third probe was used to check the exterior temperature of the side panel/chimney.
The results are interesting. Thermal equilibrium occurred at around 45 minutes with the oil chamber temperature probe delivering a reading of 178C. At that temperature the chimney under test registered an air temperature of 107C and the exterior wall of the chimney read 94C on a surface contact probe thermometer.
Throughout the test, the heater was set to its highest power level (3) and at no time did the power draw become interrupted by any thermostat action. The Dragon 4 delivers the 2KW power draw specified until such time as the ambient temperature thermostat disconnects the power to the heaters.
At the end of a 46 minute test the accumulated power consumption read 1.461KWh.
That is approximately 2KWh for the full hour.
The stated Wattages of the heaters when cool correlated well with live measurements of 904W/1120W/2000W
I think we can now see why the Dragon 4 oil filled heater has a good reputation. It runs nice and hot and has no daft behaviour such as shown in the video referenced by Wrapper. I cannot explain the reason for the difference. I can confirm that the oil in my Dragon 2 does not boil and there are no signs that the heater is in any kind of thermal distress. They call it a Dragon for a reason
Fraser
Update: I just checked the Dragon 4 on its 900W setting and thermal equilibrium occurred at 100.3C on the top of the oil chamber.
A further check at the 1100W setting showed a temperature of 115.3C on the top of the oil chamber at thermal equilibrium.