High altitude capability of Espar Hydronic 2 vs 3

[DrivenToAdventure]

Hi Everyone,

I've been reading the Espar manual and researching online all night and I'm afraid I'm still confused . Here is my issue:

I'm trying to decide between the Espar Hydronic 3 D5E and the Hydronic 2 D5E. I wrote to Espar and corresponded with them and ended up even more confused! We are planning extended travel throughout various climates and therefore need a heater capable of operating at higher altitudes occasionally. Espar told me we had to use the Hydronic 2 but I was leaning towards the Hydronic 3 and I can't figure out why it's not capable of operating at higher altitudes (the Espar product catalog doesn't mention specifically that it can't but the Espar rep told me I HAD to use the Hydronic 2. Also the heatso website says the 3 isn't capable of operating above 1500 meters).

Does anyone know what the real deal is because honestly the various Espar manuals I have contradict themselves and online info seems difficult to come by.

Thanks in advance for any guidance you can offer!

 

[loonwheeler]

AFAIK, the Espar units have two options for dealing with operating at high altitudes. A different fuel pump or a high altitude sensor that is external to the heater. I have the latter which is wired between the controller and the heater.

Is it possible the Hydronic 3 is not compatible with the high altitude sensor?

 

[DrivenToAdventure]

AFAIK, the Espar units have two options for dealing with operating at high altitudes. A different fuel pump or a high altitude sensor that is external to the heater. I have the latter which is wired between the controller and the heater.

Is it possible the Hydronic 3 is not compatible with the high altitude sensor?

That's the million dollar question I can't seem to answer!

 

[luthj]

The H3 is HAK compatible (I have one). I am not familiar with the later models.

I have never tried, but it should be possible to change the fuel pumps stroke to reduce the volume by say 20%. This would reduce the heaters output, but would prevent sooting up at higher altitudes.

There is discussion of adjustment down this page a ways.

https://www.letonkinoisvarnish.co.uk/eberspacher_fuel_2.html

You would need to take a baseline using the pump tests from the service manual. Then adjust the pump to reduce volume by the desired amount.