diff --git a/src/methods/property_solvers/multicomponent/flash/PS.jl b/src/methods/property_solvers/multicomponent/flash/PS.jl
index 6b15d642b..80968c42f 100644
--- a/src/methods/property_solvers/multicomponent/flash/PS.jl
+++ b/src/methods/property_solvers/multicomponent/flash/PS.jl
@@ -24,7 +24,7 @@ function init_preferred_method(method::typeof(ps_flash),model::EoSModel,kwargs)
 end
 
 function ps_flash(model,p,s,z,method::FlashMethod)
-    check_arraysize(model,n)
+    check_arraysize(model,z)
     if supports_reduction(method)
         model_r,idx_r = index_reduction(model,z)
         z_r = z[idx_r]
diff --git a/test/test_methods_api.jl b/test/test_methods_api.jl
index 8a2fee009..9c5f19a1f 100644
--- a/test/test_methods_api.jl
+++ b/test/test_methods_api.jl
@@ -379,7 +379,12 @@ end
     res1 = ph_flash(model,p,h,z)
     @test enthalpy(model,res1) ≈ h rtol = 1e-6
 
-
+    #test for ps_flash:
+    model = cPR(["ethane"],idealmodel = ReidIdeal);
+    s = 100;p=101325;z = [1.0];
+    h = Clapeyron.PS.enthalpy(model,p,s,z)
+    s2 = Clapeyron.PH.entropy(model,p,h,z)
+    @test s ≈ s2 rtol = 1e-6
     #examples for qt, qp flash (#314)
     model = cPR(["ethane","propane"],idealmodel=ReidIdeal)
     res2 = qt_flash(model,0.5,208.0,[0.5,0.5])