diff --git a/src/MNH/prandtl.f90 b/src/MNH/prandtl.f90
index a66ecfb7b1a052acdb70636b8b5a4eb15da5007e..b21884eca85caad98abbf43dca6a8daaa2f189a5 100644
--- a/src/MNH/prandtl.f90
+++ b/src/MNH/prandtl.f90
@@ -193,6 +193,7 @@ END MODULE MODI_PRANDTL
 !!                                              change of YCOMMENT
 !!                     2012-02 Y. Seity,  add possibility to run with reversed 
 !!                                               vertical levels
+!!                     2017-09 J.Escobar, use epsilon XMNH_TINY_12 for R*4 
 !! --------------------------------------------------------------------------
 !       
 !*      0. DECLARATIONS
@@ -366,7 +367,7 @@ END DO
 !
 DO JSV=1,ISV
   ZW2=SIGN(1.,PREDS1(:,:,:,JSV))
-  PREDS1(:,:,:,JSV)= ZW2(:,:,:) * MAX(1.E-30, ZW2(:,:,:)*PREDS1(:,:,:,JSV))
+  PREDS1(:,:,:,JSV)= ZW2(:,:,:) * MAX(XMNH_TINY_12, ZW2(:,:,:)*PREDS1(:,:,:,JSV))
 END DO
 !
 !---------------------------------------------------------------------------