diff --git a/Manuals/FDS_User_Guide/FDS_User_Guide.tex b/Manuals/FDS_User_Guide/FDS_User_Guide.tex
index 3b9beb5c0d..0cb1bbc3a1 100644
--- a/Manuals/FDS_User_Guide/FDS_User_Guide.tex
+++ b/Manuals/FDS_User_Guide/FDS_User_Guide.tex
@@ -13976,6 +13976,7 @@ \chapter{Error Codes}
 373  \> \ct{Cannot have FISHPAK_BC>0.                                             } \> Section~\ref{sec:periodic}  \\
 374  \> \ct{Numerical Instability - FDS stopped.                                   } \> Section~\ref{info:Errors}  \\
 375  \> \ct{OBST ... is VARIABLE_THICKNESS or HT3D and needs a MATL_ID.      } \> Section~\ref{info:HT3D_Limitations}  \\
+376  \> \ct{Meshes must have the same y/z bounds for TUNNEL_PRECONDITIONER.  } \> Section~\ref{tunnel_solver}  \\
      \>                                                                               \>                                     \\
 381  \> \ct{Need more spectral band limits.                                        } \> Section~\ref{info:RADI_Wide_Band}  \\
 382  \> \ct{Spectral band limits should be given in ascending order.               } \> Section~\ref{info:RADI_Wide_Band}  \\
diff --git a/Source/read.f90 b/Source/read.f90
index afab2f6bed..3d8d033324 100644
--- a/Source/read.f90
+++ b/Source/read.f90
@@ -9807,6 +9807,12 @@ SUBROUTINE READ_PRES
    IF (MAX_PRESSURE_ITERATIONS<20) MAX_PRESSURE_ITERATIONS = 20
    TUNNEL_NXP = 0
    DO NM=1,NMESHES
+      IF (NM>1) THEN
+         IF (MESHES(NM)%YS/=MESHES(NM-1)%YS .OR. MESHES(NM)%YF/=MESHES(NM-1)%YF .OR. &
+             MESHES(NM)%ZS/=MESHES(NM-1)%ZS .OR. MESHES(NM)%ZF/=MESHES(NM-1)%ZF) THEN
+            CALL SHUTDOWN('ERROR(376): Meshes must have the same y/z bounds for TUNNEL_PRECONDITIONER.') ; RETURN
+         ENDIF
+      ENDIF
       TUNNEL_NXP = TUNNEL_NXP + MESHES(NM)%IBAR
    ENDDO
    ALLOCATE(TP_AA(TUNNEL_NXP))