diff --git a/src/thermo/MixtureFugacityTP.cpp b/src/thermo/MixtureFugacityTP.cpp
index fd1cebd1b..12399fdf3 100644
--- a/src/thermo/MixtureFugacityTP.cpp
+++ b/src/thermo/MixtureFugacityTP.cpp
@@ -708,11 +708,13 @@ doublereal MixtureFugacityTP::calculatePsat(doublereal TKelvin, doublereal& mola
             }
         }
         if (!foundGas || !foundLiquid) {
-            writelog("error couldn't find a starting pressure\n");
+            warn_user("MixtureFugacityTP::calculatePsat",
+                "could not find a starting pressure; exiting.");
             return 0.0;
         }
         if (presGas != presLiquid) {
-            writelog("error couldn't find a starting pressure\n");
+            warn_user("MixtureFugacityTP::calculatePsat",
+                "could not find a starting pressure; exiting");
             return 0.0;
         }
 
diff --git a/src/thermo/PDSS_HKFT.cpp b/src/thermo/PDSS_HKFT.cpp
index 475ee36c4..e724590ee 100644
--- a/src/thermo/PDSS_HKFT.cpp
+++ b/src/thermo/PDSS_HKFT.cpp
@@ -314,10 +314,11 @@ void PDSS_HKFT::initThermo()
                 " not consistent with G and S: {} vs {} cal gmol-1",
                 sname, Hcalc/toSI("cal/gmol"), m_deltaH_formation_tr_pr);
         } else {
-            writelog("PDSS_HKFT::initThermo() WARNING: DHjmol for {} is not"
-                " consistent with G and S: calculated {} vs input {} cal gmol-1",
-                sname, Hcalc/toSI("cal/gmol"), m_deltaH_formation_tr_pr);
-            writelog("                                : continuing with consistent DHjmol = {}", Hcalc/toSI("cal/gmol"));
+            warn_user("PDSS_HKFT::initThermo()",
+                "DHjmol for {} is not consistent with G and S: calculated {} "
+                "vs input {} cal gmol-1; continuing with consistent DHjmol = {}",
+                sname, Hcalc/toSI("cal/gmol"), m_deltaH_formation_tr_pr,
+                Hcalc/toSI("cal/gmol"));
             m_deltaH_formation_tr_pr = Hcalc / toSI("cal/gmol");
         }
     }
diff --git a/src/thermo/RedlichKwongMFTP.cpp b/src/thermo/RedlichKwongMFTP.cpp
index d79fc3334..6368f435a 100644
--- a/src/thermo/RedlichKwongMFTP.cpp
+++ b/src/thermo/RedlichKwongMFTP.cpp
@@ -1289,9 +1289,9 @@ int RedlichKwongMFTP::NicholsSolve(double TKelvin, double pres, doublereal a, do
             if (fabs(tmp) > 1.0E-4) {
                 for (int j = 0; j < 3; j++) {
                     if (j != i && fabs(Vroot[i] - Vroot[j]) < 1.0E-4 * (fabs(Vroot[i]) + fabs(Vroot[j]))) {
-                        writelog("RedlichKwongMFTP::NicholsSolve(T = {}, p = {}):"
-                                 " WARNING roots have merged: {}, {}\n",
-                                 TKelvin, pres, Vroot[i], Vroot[j]);
+                        warn_user("RedlichKwongMFTP::NicholsSolve",
+                            "roots have merged: {}, {} (T = {}, p = {})",
+                            Vroot[i], Vroot[j], TKelvin, pres);
                     }
                 }
             }
@@ -1349,9 +1349,9 @@ int RedlichKwongMFTP::NicholsSolve(double TKelvin, double pres, doublereal a, do
             }
         }
         if ((fabs(res) > 1.0E-14) && (fabs(res) > 1.0E-14 * fabs(dresdV) * fabs(Vroot[i]))) {
-            writelog("RedlichKwongMFTP::NicholsSolve(T = {}, p = {}): "
-                "WARNING root didn't converge V = {}", TKelvin, pres, Vroot[i]);
-            writelogendl();
+            warn_user("RedlichKwongMFTP::NicholsSolve",
+                "root did not converge: V = {} (T = {}, p = {})",
+                Vroot[i], TKelvin, pres);
         }
     }