Immersion Heater Problem

[jimjim2991]

Hi,

I've made a water recirculation system. To heat the water, I am using:

1kW 11" Immersion Heater
+
7" 88 Degree High Temp Stat

I'm using 10L of water total, and would like to achieve a stable temperature of 70 Degrees. I was told this would easily be possible (and higher) using what I've listed. However, I'm only managing to achieve, at best, 67 Degrees. The stat is on the highest setting, but still no joy!

Does anyone have any idea why this is not working?

EDIT: It does KIND OF reach 70C, but it's very uncertain about staying there, dropping down to mid-sixties often.

 

[Lucien Nunes]

The maximum achieveable stable temp doesn't depend on the quantity of water but the ease with which it can lose heat to the outside world, which depends on exposed surface area of vessels & pipework, evaporative surface etc. Presuming your stat never goes off, evidently your 'system' dissipates 1kW at (67-ambient)°C. Or whatever the actual input power to your element is, as it drops with the square of voltage. A 1kW 240V element only delivers 840W at 220V.