diff --git a/src/KSPACE/pair_lj_charmmfsw_coul_long.cpp b/src/KSPACE/pair_lj_charmmfsw_coul_long.cpp
index 9ba59b6995c759478e1546902b5dc2bd2052841c..30d8ab64b60f086c89d328402aa0b2ba8c45c282 100644
--- a/src/KSPACE/pair_lj_charmmfsw_coul_long.cpp
+++ b/src/KSPACE/pair_lj_charmmfsw_coul_long.cpp
@@ -65,8 +65,12 @@ PairLJCharmmfswCoulLong::PairLJCharmmfswCoulLong(LAMMPS *lmp) : Pair(lmp)
 
   // switch qqr2e from LAMMPS value to CHARMM value
 
-  if (strcmp(update->unit_style,"real") == 0)
+  if (strcmp(update->unit_style,"real") == 0) {
+    if ((comm->me == 0) && (force->qqr2e != force->qqr2e_charmm_real))
+      error->message(FLERR,"Switching to CHARMM coulomb energy"
+                     " conversion constant");
     force->qqr2e = force->qqr2e_charmm_real;
+  }
 }
 
 /* ---------------------------------------------------------------------- */
@@ -96,8 +100,12 @@ PairLJCharmmfswCoulLong::~PairLJCharmmfswCoulLong()
 
   // switch qqr2e back from CHARMM value to LAMMPS value
 
-  if (strcmp(update->unit_style,"real") == 0)
+  if (update && strcmp(update->unit_style,"real") == 0) {
+    if ((comm->me == 0) && (force->qqr2e == force->qqr2e_charmm_real))
+      error->message(FLERR,"Restoring original LAMMPS coulomb energy"
+                     " conversion constant");
     force->qqr2e = force->qqr2e_lammps_real;
+  }
 }
 
 /* ---------------------------------------------------------------------- */
diff --git a/src/MOLECULE/pair_lj_charmmfsw_coul_charmmfsh.cpp b/src/MOLECULE/pair_lj_charmmfsw_coul_charmmfsh.cpp
index f1366a379d03100a429f1e901ed62c7b47f65f85..0d2159b671ddf84969954c78b809ebef065ea560 100644
--- a/src/MOLECULE/pair_lj_charmmfsw_coul_charmmfsh.cpp
+++ b/src/MOLECULE/pair_lj_charmmfsw_coul_charmmfsh.cpp
@@ -50,8 +50,12 @@ PairLJCharmmfswCoulCharmmfsh::PairLJCharmmfswCoulCharmmfsh(LAMMPS *lmp) :
 
   // switch qqr2e from LAMMPS value to CHARMM value
 
-  if (strcmp(update->unit_style,"real") == 0)
+  if (strcmp(update->unit_style,"real") == 0) {
+    if ((comm->me == 0) && (force->qqr2e != force->qqr2e_charmm_real))
+      error->message(FLERR,"Switching to CHARMM coulomb energy"
+                     " conversion constant");
     force->qqr2e = force->qqr2e_charmm_real;
+  }
 }
 
 /* ---------------------------------------------------------------------- */
@@ -80,8 +84,12 @@ PairLJCharmmfswCoulCharmmfsh::~PairLJCharmmfswCoulCharmmfsh()
 
   // switch qqr2e back from CHARMM value to LAMMPS value
 
-  if (strcmp(update->unit_style,"real") == 0)
+  if (update && strcmp(update->unit_style,"real") == 0) {
+    if ((comm->me == 0) && (force->qqr2e == force->qqr2e_charmm_real))
+      error->message(FLERR,"Restoring original LAMMPS coulomb energy"
+                     " conversion constant");
     force->qqr2e = force->qqr2e_lammps_real;
+  }
 }
 
 /* ---------------------------------------------------------------------- */