If you are going to have to replace the transducer on a yearly basis, maybe you should have bought more than 1.
How big an order would you have needed to get free shipping?
I do not envisage having to replace it annually, I assume because I left it connected when closing down for the summer, that caused the problem, and as far as I can see, there is no discount for multiple orders
I had the same problem but fortunately it was still in warranty and Dimplex supplied a transducer complete. I disamantled the old one and found that the problem was due to calcification on the disc. A soak in diluted brick cleaner solved it. Solution is to empty the tank and dry out the transducer if the fire is not going to be used for a while.