Sorry for the misleading wording.
I meant "less than 760kg of fuel in each" tank. Below this level the heat exchanger are not any more fully surrounded by fuel.
Originally Posted by Avenger
...Do you know if the case drain fliter has a bypass to prevent overheat in case of blockage?...
No, there is no bypass.
If the filter starts to produce more resistance due to contamination, you have a increase of the EDP pressure. This is caused by the way the EDP regulates the output pressure.
So, a increasing pressure above the normal range (approx. 2800 - 3200 PSI)
could be an indication for a "dying" EDP.