Watchman oil tank alarm/level indicator

[Rollerball]

About 4 years ago I purchased one of these:

http://www.sensor-systems.com/products/watchmanalarm.aspx

It worked fine for a few years then about a year ago the receiver started showing that the tank was full when it wasn't. It also sometimes sounded the alarm for no reason. I swapped out the button cell battery in the transmitter (the red part that screws into the top of the oil tank) but that didn't help.

I gave up and simply unplugged the receiver.

Today I decided to try it again - as always, it shows the tank is full when it isn't.

I've tried 'pairing up' the receiver and transmitter again as per the instructions but even though that appears to be successful (no errors given) the bars on the receiver still indicate that the tank is full.

No DIP switches have been changed on the receiver since I set it up 4 years ago (when it was working).

Any ideas please?

 

[oilhead]

Buy a new one, or discipline yourself to dip every week.

 

[Rollerball]

A new one costs about 80 quid on average - I was hoping to be able to fix the issue with this one.

 

[Bosswhite]

A new one costs about 80 quid on average - I was hoping to be able to fix the issue with this one.

I use one of these cost 20p, depending on length
no electronics to go wrong, simple, easy to use, dosent need replacement batteries either