Another Eberspacher problem

[Ian_Edwards]

The Eberspacher which is a 2007, 5kW, Hydronic 5, was taken out and fully professionally serviced last winter, however the unit has developed an intermittent fault.

When I turn it on first thing in the morning the unit starts up normally and gets to a point where the matrix heaters turn on, i.e. the system is up to working temperature, it then runs for a few minutes 5 or 6, but I've never actually timed it and then shuts down.

There is no error message on the display 701 (a 7 day timer).

It doesn't do it every morning!

If I restart it, it runs normally for the rest of the day.

I’m unsure what to do about it any thoughts?

 

[David2452]

The Eberspacher which is a 2007, 5kW, Hydronic 5, was taken out and fully professionally serviced last winter, however the unit has developed an intermittent fault.

When I turn it on first thing in the morning the unit starts up normally and gets to a point where the matrix heaters turn on, i.e. the system is up to working temperature, it then runs for a few minutes 5 or 6, but I've never actually timed it and then shuts down.

There is no error message on the display 701 (a 7 day timer).

It doesn't do it every morning!

If I restart it, it runs normally for the rest of the day.

I’m unsure what to do about it any thoughts?

Some of the vehicle specific 701 timers have a time limiter but as it doesn't every time that is less likely. It is possible that there is a thermostat issue or air in the system. Is it a closed loop pressurised install or one of those awful header tank types, they often play up sooner or later in one way or another. When you write "professionally serviced" I assume you mean by an authorised ebo dealer?

 

[pcatterall]

Could be overheat shut down possibly due to air in water which is purged by the time you re-start.
Also possibly a fuel issue where your heater starts and runs for a short time on fuel in the pipe from pump to heater then stops when their is no fuel in the pipe but restarts when the air has been purged from the pipe.

 

[Ian_Edwards]

Yes, it's a header tank system, at least I think it is, there is certainly a "feed and expansion tank" like you'd get on an engine close to the Eberspacher.

Yes, it was an authorised Eberspacher dealer, the unit was taken out serviced and then bench tested and deemed to be in perfect working order in March this year.

The unit still shuts down even when I'm only using it to heat the domestic hot water, i.e the thermostats on the 3 matrix heaters are turned down, so that the little red light comes on the individual thermostats (one for each matrix),but the matrix heaters aren't powered up.

It could be fuel, I've had issues with bits of what I think is sealant, blocking the fire safety valve on the main engine. However, I would have thought that if it was a fuel blockage causing the problem, I wouldn't just see an intermittent problem on start up. Once going the Ebershacher it will run for hours without any problem, including getting bounced around in a seaway.

I guess it could be an intermittent problem in the controller/timer. I'm not using the timer function, other than to press the buttons to put the Eberspacher on for a fixed period of time, usually at least 2 hours in the morning. The 7 day timer seems unnecessarily complex and difficult to use, so I just don't bother with it. I just put the Eberspacher on first thing in the morning when a get up to make the batter half a cup of tea.

Is there a marginal sensor which could cause a shut-down and then dry-out/warm-up or something whilst the Eberspacher is going thro' it's shut down and restart cycles?

 

[contessaman]

sorry to hear you are having trouble. just a thought - not sure if its applicable but my D1lCc air heater did this. It would run up on its turbo setting for 5 minutes then shut down. The fault for me was the rheostat controller. It always runs at maximum for this five mins or so after startup, then it looks for its datum resistance. my rheostat would sometimes go open circuit so when the eber got to the stage of looking for the resistance, it wouldnt find any so it would initiate shutdown. I bought an expensive brand new rheostat which fixed it for a while but then this one broke to (maybe im ham fisted?!). Anyways, in the end I found a website that said what the resistance should be and I just made my own controller with a 3 position switch with three resistor values so I got lo-med-hi and another toggle switch for on-off. working perfectly for years like this.

Im sure yours is more modern than mine but if its not getting the datum then it could be producing the fault - which has the same shutdown as overheating.
so for diagnosis id check it aint overheating first then find a way of hotwiring your eber to bypass the controller and substitue some resistors of the correct value.

 

[David2452]

Ah, your second post gives more clues, we can assume with a fair degree of certainty the service was done properly and the kit to verify all was OK was available and used. You say thermostats, one of the no no things on coolant based systems is TRVs on radiators or matrix, this causes the heater to cycle too much and causes premature coking but what can also happen is that thermostats can stick in such an install and give similar symptoms to what you have. The heater thinks it has reached temperature and shuts down due to low volume of circulated coolant, a thermostat opens due to conduction during the shutdown and the second attempt is then successful. If I were attending something with these symptoms I would flush the system, remove the header and replace it with an accumulator, auto bleed pot and pressure loop, remove (or crank up to maximum) the TRVs, refill with 15% antifreeze and a little more inhibitor. The 50% Eber recommend is a hangover from truck pre heater installs, glycol is a poor heat transfer medium and the more you have in the less efficient the system at carrying heat away from the exchanger. It certainly seems the heater diagnostics believe there is no fault so my focus would certainly be in other areas of the system. Easy for me to say as I would have as a first action connected EDITH up and seen what the sensors were reporting during the unexpected shutdown so would be able to move on to other areas with some surety.

Yes, it's a header tank system, at least I think it is, there is certainly a "feed and expansion tank" like you'd get on an engine close to the Eberspacher.

Yes, it was an authorised Eberspacher dealer, the unit was taken out serviced and then bench tested and deemed to be in perfect working order in March this year.

The unit still shuts down even when I'm only using it to heat the domestic hot water, i.e the thermostats on the 3 matrix heaters are turned down, so that the little red light comes on the individual thermostats (one for each matrix),but the matrix heaters aren't powered up.

It could be fuel, I've had issues with bits of what I think is sealant, blocking the fire safety valve on the main engine. However, I would have thought that if it was a fuel blockage causing the problem, I wouldn't just see an intermittent problem on start up. Once going the Ebershacher it will run for hours without any problem, including getting bounced around in a seaway.

I guess it could be an intermittent problem in the controller/timer. I'm not using the timer function, other than to press the buttons to put the Eberspacher on for a fixed period of time, usually at least 2 hours in the morning. The 7 day timer seems unnecessarily complex and difficult to use, so I just don't bother with it. I just put the Eberspacher on first thing in the morning when a get up to make the batter half a cup of tea.

Is there a marginal sensor which could cause a shut-down and then dry-out/warm-up or something whilst the Eberspacher is going thro' it's shut down and restart cycles?