Eberspacher Hydonic 10 water heater reluctant to fire up.

[silversailor75]

Has anyone any suggestions that would explain a starting problem?
The heater has progressively become reluctant to fire up, needing two attempts, then three attempts and then four attempts. At this point I stripped it down, replaced the glowplug and cleared some hard carbon deposits from the burner and assumed I had found the cause. However, on re-installation it wont light even after 10 attempts although some white exhaust vapour starts to appear so it is obviously trying!
It is fitted with an air intake silencer. Do these clog up and need replacing?
It doesn't seem to be a component failure since the condition has only advanced gradually.
Unfortunately the boat is in Southern Belgium and nowhere near a service agent so I am up the proverbial creek at present.

 

[Ian_Edwards]

I've got a Hydronic 10, and it's been reluctant to start in the past, although it's started 1st time over this winter (touch wood).

The faults so far have always been related to the glowplug.

When you replaced the glowplug and decoaked it, did check the flame sensor and the over temperature sensor?

If you're sure the glow plug is working, then it may be worth checking them, but you should be able to see the fault from the control box.

From the manual:

Resistance Values
[TABLE="width: 500"]
[TR]
[TD]Temperature sensor[/TD]
[TD]-25°C 650 ohms
+25°C 1000 ohms[/TD]
[/TR]
[TR]
[TD]Flame sensor[/TD]
[TD]-25°C 900 ohms
+25°C 1100 ohms[/TD]
[/TR]
[TR]
[TD]Overheat sensor[/TD]
[TD]-25°C 150 K ohms
+25°C 10 K ohms[/TD]
[/TR]
[TR]
[TD]Glow Pin[/TD]
[TD]~2 ohms[/TD]
[/TR]
[TR]
[TD]Fuel Metering Pump[/TD]
[TD]~20ohms[/TD]
[/TR]
[/TABLE]

The other common fault is low voltage at the burner during start-up. Usually a poor (corroded?) connection.

I have various manuals for the Hydronic 10, I can post them on dropbox if you don't have them and think they would be useful.

If you've tried starting 10 times the burner will have quite lot of diesel in it, this will produce white smoke when it eventually fires, enough to hide a destroyer, so make sure you're moored head to wind and that there is no one astern of you.

 

[savageseadog]

Low voltage at the heater due to corroded connections, switches cabling too small. Use 10mm square cable in a typical boat.

 

[silversailor75]

Thanks for that Ian - I do have the manual which I downloaded off the net but unfortunately my system wasn't fitted with the Eber control box and has a Theben Ramses programmer instead and it doesn't show fault codes of course.
Don't I know about the white cloud after several start attempts. The whole marina was rendered invisible for about 5 minutes much to my embarrassment!
Must admit I haven't checked connections - could be a bit of resistance there with corrosion but batteries are huge and permanently on the top line with solar panels so it won't be voltage drop for that reason.
Regards
Tom

 

[Ian_Edwards]

I did say enough to hide a destroyer!
I inadvertently wiped out a barbecue about 2 years ago.
Cap in hand, or should I say, bottle of wine in hand I apologised.