a lousy product

I have three of these controls in use.
Yes, I have no E3 error
Yes, if they run dan run
No, the temperature in the room is not the temperature I set.
AND! the batteries should last no winter.
Then it gets interesting.
The controllers control on and you realize it only when you can no longer stand it from heat in the room and looks up.
Then, the part has just adopted without comment and it heats like crazy.
I'm sick of the circus now and throw these things on scrap.
Too bad for the money if you can not even fit a beeper that signals when the batteries are all.
Oh ... environmental protection ..... With batteries is also sometimes a problem. Since these have less voltage such as batteries (1.2 volts instead of 1.5 volts), it is not guaranteed that the controller is working properly.
In the description, is that you can control with teach batteries. I wonder how that works when the display is dead?