On Sunday morning I was looking forward to a lazy few hours in my PJs. The plan called for a hearty breakfast, freshly ground coffee, some light reading and a hot shower before deciding what to do for the reminder of the day. Regrettably, the unexpectedly cold water from the showerhead put an end to an otherwise agreeable time.

Further investigation was required and normally, I’d put this event down to excessively long showers by my teenage daughter but as she was still in bed, that wasn’t the problem on this particular morning. I traced the fault to this, the Horstmann Channel Plus H27XL water and heating controller. It’s a simple two channel 7 day timer that controls my gas boiler, and after working flawlessly for many years, it appeared to be completely dead. I checked the mains power to the controller was still on and no amount of button-pushing could bring the device back to life.

At this point, it looked to be time for a new unit. Online, the price for a replacement H27XL looked to be around GB£60-£70, but as I was browsing for the best price, I came across reviews and posts complaining about an internal battery. Although used for backing up the timer settings during power failures, once the battery ran out, the controller stopped working completely. Completely.

The H27XL is held together with two screws, a crosshead on the left and a Torx-style on the right, and both covered with stickers. Horstmann certainly aren’t making it easy to open up the controller. Once inside there’s a standard CR2450 lithium battery held in place with a couple of tiny spot welds. A battery that costs less than £3. Five minutes of prying with a flat-bladed screwdriver extricated the battery from the contacts.

A further minute and some sticky tape (it’s only 3V DC but use insulating tape if you want to be really safe) and I have a fresh battery powering the unit, though it still looks dead at this point. I’ll replace the sticky tape with a battery holder once I find a suitable model over at Farnell.

I put it all back together and fitted the controller back onto its connecting base plate. Straightaway the H27XL powered on and fired up the boiler. 20 minutes later and I was back relaxing in the shower with hot water. Aaah!

I can’t say whether this is deliberate obsolescence by design but it doesn’t look good. The battery is always going to run out at some point and it’s poor that it’s not user-replaceable, especially in this era of trying to reduce e-waste. All I can say for sure is that I won’t be buying any Horstmann products in the future.

(Horstmann Controls now seems to be Secure Meters and is entirely unrelated to the German firm Horstmann Gmbh.)