Function well, programming is so, life expectancy short

I bought 5 pieces HR20 Styles. You are now a year in operation. They work well as long as you are not broken.
Advantages:
- Tolerable volume in the bedroom (as opposed to HR30)
- Useful adapter for all of my radiator.

Is the radiator valve sluggish then it is essential to the full-stroke mode use otherwise the valve remains a few days in an open or closed state. In Full-stroke mode the battery is empty after one year.

Disadvantages:
- Will to very stiff valves not with battery because the engine is insufficient capacity. HR30 is better off.
- No single-shift points but always in pairs of programming on and switch-off time, but you can let one of the two periods are to be undefined. This of course you lose half a program memory space. This must, however, make even so when midnight is exceeded because both switching times of a pair must be on the same day.
- Only two temperatures to choose from. But in the bathroom, I would like before taking a shower two degrees separately
- Legibility especially to hidden radiators behind the sofa bad. There's HR30 with lighting and Monster display better.

I had the first failure yesterday. A regulator has always resets the attempt to start the engine. The battery (Sanyo Eneloop) was full. This was caused by a battery contact:

The battery contacts begin to corrode in from the edge. The cut edge on the sheet metal is not protected. The corrosion travels slowly in the area. The spring tension does not keep the batteries particularly strong. It is the regulator in the bathroom, so I suspect a connection with moisture. Since I am single and therefore not showered 10 times a day, I can not quite understand it.