In the spring our onboard Webasto 2010 dwb diesel heater was working great, but after not running it all summer we attempted to fire it up to keep the boat warm, and no go. When we turned it on we just heard a clicking sound that was the ignition trying to get it to fire.

Here is a great diagram that I found that is almost identical to our webasto plumbing layout.

After a lot of help from my son George and lots of investigation of all the things it could be causing it to fail. We checked power to the unit, and we checked the air intake, which some people said if it was clogged would prevent it from starting up, we checked that it was actually getting diesel, by putting a bubble pump inline and manually pumping diesel to confirm the filters were not clogged and the and fuel was getting there. All that with no luck.

Next after giving up, I decided to call the local Webasto tech, the only one in the county, and since we keep our boat at a remote neighborhood marina, they said they would call me next time they were headed our way, and that based on the symptoms it was probably the control unit. Which didn’t mean much to me at that point. After 3 weeks of waiting for them to be in our area, and after our first freeze of the season, I decided to go online and purchase a new control unit, and give it a try. I found the unit online for just over $300 for sale in the UK, with 4 day shipping available to get it to my house in the US. I ordered on a Thursday, paid with Paypal (which always worries me), and the unit arrived on Tuesday.

Again with the help of George we swapped out the control unit which is simply a small computer component in a box with a bunch of wired connected.

Here is the original unit and the new unit side by side.

After replacing the control unit, the Webasto diesel heater started up and ran beautifully. We now have the diesel heat working again.

If you are looking to do the same, be sure that you are getting the right unit for your system, either a 24 or 12v control unit. I almost accidentally ordered a 24v unit, which would not have worked with my system.

There are a couple outstanding tasks, the control unit is mounted upside down, I just need to flip it over. Also the heater in the stateroom is not working. I need to investigate why, however the engine heat at the salon heat are working fine.

Hooray! Victory on the Webasto diesel heater repair.