diff --git a/opm/core/simulator/WellState.hpp b/opm/core/simulator/WellState.hpp
index adf3fb244..313914587 100644
--- a/opm/core/simulator/WellState.hpp
+++ b/opm/core/simulator/WellState.hpp
@@ -59,8 +59,10 @@ namespace Opm
                         bhp_[w] = well_controls_get_current_target( ctrl );
                     }
 
-                    // Initialize well rates to match controls if type is SURFACE_RATE,
-                    // otherwise set to a small rate with the correct sign.
+                    // Initialize well rates to match controls if type is SURFACE_RATE.
+                    // Otherwise, we cannot set the correct value here, so we assign
+                    // a small rate with the correct sign so that any logic depending on
+                    // that sign will work as expected.
                     if (well_controls_well_is_open( ctrl ) || (well_controls_get_current_type(ctrl) == SURFACE_RATE)) {
                         const double rate_target = well_controls_get_current_target(ctrl);
                         const double * distr = well_controls_get_current_distr( ctrl );