The WS5029 has a rain gauge which can be fully serviced (and replaced).
If the rainfall stops working you'll need to get the vane down from it's position and remove the click lock top from the gauge - this will expose the sea-saw and the sensor for your review.
Caution: Please take care when undoing the rain gauge's click top lid. Insects can enter the gauge and then they grow too large to be able to leave, you may find there is a resident inside the lid or under the sea-saw
The sea-saw should be mounted on a small metal spindle with a piece of hot glue holding it to the mounting position, there should be no impediment to the movement of the sea-saw.
If you do have a spider in residence then please allow the resident the opportunity to leave before cleaning out the sea-saw area allowing the sea-saw to move freely again.
After they've left you can use a surface spray on the inside of the funnel (not on the sensor) to keep insects from coming back for 6 months. Wait for the spray to dry before returning the lid to the gauge.
If there's no resident in your gauge, or you find that cleaning out the gauge gives no solution to your lost reading, then please get in touch for further assistance.
Article verified: WS5029, Wireless Data Centre, iWeather