One of my recent rather obscure jobs was to fix a Watchman heating oil tank sensor. This device lets the owner know (via a radio signal to a plug giving an audible warning) that their heating oil is running out and best to ring up the supplier pronto. This device was installed many years ago at a church here in Malmesbury, and after running out of oil with no warning a couple of times (and parishioners experiencing a rather cold church), some knowledgeable souls pointed out that the tank sensor was remaining silent about the matter. A brief investigation led to the culprit being identified as the battery pack for the sensor inside the tank. This beastie is a simple copper tube filled with 4 AAA batteries and a coaxial connector, but replacements are expensive/difficult to obtain as these sensor units are no longer marketed.
Thankfully, YouTube have plenty of videos showing how you can carefully repair the battery holder by removing the end cap, replacing the batteries and reassembling the unit. A few minutes fiddling has now resolved the transmitter woes, the church is once again feeling snug and parishioners will no longer feel the need to wrap up like they were going for a hike up Everest.
Talking Electrical Ltd 