I plan to swap Eberspacher Airtronic D2 in my boat for an S3 D2L. I'll also replace the 801 controller with an EasyStart Select. I see that you sell a wiring harness for this conversion: Part Number: E6970. Can you tell me how successful these typically are? I had a couple of Espar dealers in the States recommend against it, but I don't think they had experience with this conversion harness. Thanks!

We have supplied and installed many 100s of these Eberspacher Airtronic conversion harnesses over last 2-3 yrs, without issue, or warranty. They are a tremendous time saver if the old existing wiring harness is not totally accessible. A successful solution.

Probably perhaps  the US Espar dealers do not recommend them because they do not have them?

That said – if you have the time and necessary access to replace the heater main wiring harness, then that could be considered the very optimum solution because you'll be using a new harness, rather than re-using an old harness. Honestly though, no complaints so far with this product.

I’d always opt for the Easystart Pro above the Easy Start Select controller

1. Added timer functionality ,
2. A much better diagnostic tool
3. Importantly Includes an integrated temp sensor that can be used to regulate heater output, hence cabin temperature - similar the 801. With an ES Select you would typically need to purchase in addition a temp sensor for a boat install.