diff --git a/biosteam/_system.py b/biosteam/_system.py
index 95df082a4..df9fd9527 100644
--- a/biosteam/_system.py
+++ b/biosteam/_system.py
@@ -1494,7 +1494,7 @@ def set_tolerance(self, mol: Optional[float]=None, rmol: Optional[float]=None,
         if mol is not None: self.molar_tolerance = float(mol)
         if rmol is not None: self.relative_molar_tolerance = float(rmol)
         if T is not None: self.temperature_tolerance = float(T)
-        if rT is not None: self.temperature_tolerance = float(rT)
+        if rT is not None: self.relative_temperature_tolerance = float(rT)
         if maxiter is not None: self.maxiter = int(maxiter)
         if method is not None: self.method = method
         if algorithm is not None: self.algorithm = algorithm