Putting a switch in the heating circuit.

[Bodach na mara]

When my Eberspacher system was installed, the installer did not install a master switch. He told me that he never did, as it was important that the system was allowed to complete its full shut-down cycle and that he had had to replace several boilers where the owners had turned off the master switch when leaving the boat, forgetting that the boiler was on, thus damaging the boiler from overheating. Unfortunately, I seem to have used rather a lot of diesel over the last month and found yesterday that the control unit was set with the presets ON, thus every day, I have been heating an empty boat from 07.30 to 08.30. I suspect that this has gone on since the last visit of my grandson, who loves pressing buttons!

What I now want to do is rewire the system so that it is controlled by the main switch, or fit a new master switch for the heating alone, but ideally I want the clock (control) unit to remain connected to the battery at all times. Anyone got any ideas?

 

[pmagowan]

Doesn't it have an off button? Your installer is correct.

 

[lw395]

IIRC there is a wire which the controller/timeswitch sets to 12V to fire the eber.
If you put a relay or transtor/FET switch in this line, you could make it so that the eber cannot be started without the main battery isolator being on.
But would continue its shut down cycle if you stopped it by turning the isolator off.
A relay would be easy to do, but would draw some milliamps the whole time the battery switch was on. Perhaps 80mA?

 

[Bodach na mara]

There is a shut-down button (which doubles as the on button) but no off button. The presets button toggles the presets on/off. But it is hard to see whether the preset thing is set on or off

 

[prv]

I have mine wired via the boat master switch, with a notice next to it warning not to switch off until the heater has finished shutting down. In practice it's unlikely that we would be running the heater shortly before leaving the boat anyway. I don't have a separate panel switch for the heater, as some well-meaning person might switch it off as we leave for the pub or whatever during a cruise. The boat master only gets turned off by the skipper when packing up at the end.

Pete

 

[fireball]

we put our eber in post the main switch - I know why your installed did it on the battery side and that is technically correct, but I wanted to know that once I turned the switch off, power was OFF on the boat.

I don't know how practical it is, but I would assume your eber has a fuse in the main line - possibly you could just remove the fuse whilst away from the boat for days ... ?

Alternatively, our eber controller was switched from the main panel - turn that off and the eber will start it's shutdown procedure and turn off properly (assuming the 12v to the eber itself was left on!).