diff --git a/src/MNH/tridz.f90 b/src/MNH/tridz.f90
index 4a74457910674c6edca3bf6f463ba8ed82fda929..2d93c3386fbeb5da15cffffbdd65622bb7449886 100644
--- a/src/MNH/tridz.f90
+++ b/src/MNH/tridz.f90
@@ -179,6 +179,7 @@ USE MODD_CONF
 USE MODD_LUNIT_n, ONLY: TLUOUT
 USE MODD_PARAMETERS
 !
+USE MODE_FFT,            ONLY: SET99
 USE MODE_ll
 USE MODE_MSG
 !JUAN P1/P2 SPLITTING
@@ -630,11 +631,9 @@ ELSE
 ! at the upper and lower levels PBFB is computed using the Neumann
 ! condition
 !
-  PBFB(IIB:IIE,IJB:IJE,IKB-1) = -0.5 * ( PRHOM(IKB-1) + PRHOM(IKB)   ) /  &
-                               ZDZM(IKB)   **2
+  PBFB(IIB:IIE,IJB:IJE,IKB-1) = - 0.5 * ( PRHOM(IKB-1) + PRHOM(IKB)   ) / ZDZM(IKB)   **2
   !
-  PBFB(IIB:IIE,IJB:IJE,IKE+1) =  0.5 * ( PRHOM(IKE)   + PRHOM(IKE+1) ) /  &
-                               ZDZM(IKE+1) **2
+  PBFB(IIB:IIE,IJB:IJE,IKE+1) = + 0.5 * ( PRHOM(IKE)   + PRHOM(IKE+1) ) / ZDZM(IKE+1) **2
 !
 IF (HLBCX(1) == 'CYCL' .AND. .NOT.(L2D) ) THEN
    !JUAN
@@ -695,7 +694,10 @@ DEALLOCATE(ZEIGEN_ll)
 !              -------------------------------------------------------
 !
 !        8.1 x lateral boundary conditions
-!                  
+!
+!Initialise PTRIGSX and KIFAXX to allow comparisons (they are not fully set in SET99)
+PTRIGSX(:) = XUNDEF
+KIFAXX = NUNDEF
 CALL SET99(PTRIGSX,KIFAXX,IIMAX_ll)
 !
 ! test on the value of KIMAX: KIMAX must be factorizable as a product
@@ -728,6 +730,9 @@ ENDIF
 !       8.2 y lateral boundary conditions
 !
 IF (.NOT. L2D) THEN 
+  !Initialise PTRIGSY and KIFAXY to allow comparisons (they are not fully set in SET99)
+  PTRIGSY(:) = XUNDEF
+  KIFAXY = NUNDEF
   CALL SET99(PTRIGSY,KIFAXY,IJMAX_ll)
   !
   ! test on the value of KJMAX: KJMAX must be factorizable as a product