Eberspacher Heater Puzzle

[Dockhead]

I had my Hydronic 10 professionally serviced, but when they put it back in, it seemed to have a bad water pump.

The damned pump cost $500 or something insane, so I cast around and finally found an entire used heater with a pump. But the pros who were supposed to finish the job disappeared.

I'm back on my mooring without shore power and really need this heater. So I took the pump off myself, installed it, hooked it up, put antifreeze in the system, bled it, and started it up.

The heater starts and runs and makes heat, goes into full power mode, but then suddenly shuts down. I don't understand why. One time it even ran long enough for my fan coils to start up.

The water pump is working fine and I can hear the water circulating. I've bled and rebled the system and I'm sure that's ok. All the cables are well attached.

I realize that it is unlikely that anyone could diagnose this without an error code. I do have the diagnostic instrument, but I don't have the software. I'll get that tomorrow and we'll see what code is set.

Meanwhile -- any guesses? Anyone encounter this problem?

[PDScott]

Just a guess but I would suspect a thermal couple is shutting the unit down.

[Dockhead]

Originally Posted by PDScott

Just a guess but I would suspect a thermal couple is shutting the unit down.

That's a reasonable guess, but which one, based on this behavior pattern?

Don't think it's the flame sensor, unless it's some kind of delayed reaction.

[PDScott]

Originally Posted by Dockhead

That's a reasonable guess, but which one, based on this behavior pattern?

Don't think it's the flame sensor, unless it's some kind of delayed reaction.

I would clean the flame sensor with super fine emery and give it a try. Had a stove that had a problem similar to yours and a tech advised me to try that. It worked with no problems after the cleaning.

Hopefully there will be others on the forum that are far more informed than I Good luck Peter

[Dymaxion]

Try to find the manual for your heater online. They have a good troubleshooting section. There will be 2-3 thermo couples or sensors controlling the show. Some do a complete shut off, the flame detector being one since you don't want the fuel pump pushing fuel into the chamber where it would just pool. Good luck.

[Dockhead]

Originally Posted by Dymaxion

Try to find the manual for your heater online. They have a good troubleshooting section. There will be 2-3 thermo couples or sensors controlling the show. Some do a complete shut off, the flame detector being one since you don't want the fuel pump pushing fuel into the chamber where it would just pool. Good luck.

Thanks; yes I have the manual.

It's pretty hard to follow as it's a bad translation (the original German would be easier).

It assumes that you have the diagnostic code, and tomorrow I'll get the software so I can use my tool. I'll report here what I figure out.

[Dockhead]

Another piece to the puzzle:

IF I start it when my generator is running, bringing the system voltage up to 28 volts (as opposed to 25 or so), then it starts and runs for a while, long enough for the fan coils to come on.

The fan coils blow only lukewarm, and the system shuts down after 15 minutes or so.

Hmmmm.

I can't imagine how the voltage influences it -- the generator-off voltage is well within parameters (20 to 30 volts).

Almost seems like there is some problem with circulation of the coolant, leading to shutdown for high coolant temperature at the heater.

Hard to imagine what that could be, though. There's no thermostat, the pump is obviously and audibly running and I can hear coolant running through the unit.

Hmmm.

[Dockhead]

I wonder if I've connected the circulation pump backwards?

Would it run backwards?

When I was bleeding the supply side, it seemed to have a lot of pressure in it.

That would seem to indicate a blockage or a valve shut off, but there aren't any valves, and impossible to imagine what could be blocking it.

But hooking it up backwards, I could imagine

[River Cruiser]

You may be able to test that by swapping the DC +/- pump wiring and reverse the pump rotation.


Sent from my iPad using Cruisers Sailing Forum

[Dockhead]

Originally Posted by River Cruiser

You may be able to test that by swapping the DC +/- pump wiring and reverse the pump rotation.


Sent from my iPad using Cruisers Sailing Forum

Exactly what I was thinking of. Guess it couldn't hurt anything?

?

[sailorchic34]

Originally Posted by Dockhead

Exactly what I was thinking of. Guess it couldn't hurt anything?

?

The pump would run backwards and flow and pressure would be effected/ reduced.

[Dockhead]

Originally Posted by sailorchic34

The pump would run backwards and flow and pressure would be effected/ reduced.

The point is maybe it's running backwards now. The wires are almost indistinguishable and it wouldn't be the first time I wired something up backwards

[Sandero]

Can you figure out which way it runs and if it is running the way it is intended to? If not... why not?

[Dockhead]

Originally Posted by Sandero

Can you figure out which way it runs and if it is running the way it is intended to? If not... why not?

I could take the hoses off and turn it on. But that would make a huge mess.

I'd rather just reverse the wires, if running backwards wouldn't damage anything.

Would it?

[Dockhead]

OK, so I tried reversing the wires. The pump runs and sounds ok, but the result is exactly the same.

I finally reached the engineer who was working on it -- he had gone on vacation without finishing the job!! And he's backed up with work and can't do anything before Monday

I asked him to tell me what to try myself.

He said: these are all the symptoms of an air lock in the system preventing circulation, so try to purge it.

This system (unlike my engine calorifier loop) is very well designed with the heater at the high point in the system, a high header tank, and a purge valve. I've never had problems with air in it. I did of course fill it up carefully and open the purge valve and burp the hoses, at the very beginning. But I guess I will do it again. I doubt this is the problem, because when I replaced my calorifier, which is at the low part of the system, I drained the entire system. When I was finished, all I did was fill up and refill the high header tank, and did not have the slightest problem. No burping purging or anything was required -- the air came straight up the pipes and out.

He also said check the voltage at the heater.

That was all he could suggest , and I'm on my own again, at least for a few days. Getting tired of having no heat.