diff --git a/src/grib_accessor_class_unsigned.c b/src/grib_accessor_class_unsigned.c
index 37200e0e6..87dd69ff3 100644
--- a/src/grib_accessor_class_unsigned.c
+++ b/src/grib_accessor_class_unsigned.c
@@ -244,7 +244,7 @@ int pack_long_unsigned_helper(grib_accessor* a, const long* val, size_t *len, in
                 }
                 if (nbits < 33) {
                     unsigned long maxval = (1UL << nbits)-1;
-                    if (v > maxval) {
+                    if (maxval > 0 && v > maxval) { /* See ECC-1002 */
                         grib_context_log(a->context, GRIB_LOG_ERROR,
                                 "Key \"%s\": Trying to encode value of %ld but the maximum allowable value is %ld (number of bits=%ld)\n",
                                 a->name, v, maxval, nbits);