diff --git a/src/bacnet/basic/service/h_cov.c b/src/bacnet/basic/service/h_cov.c
index 77bbabef..d0ef1d01 100644
--- a/src/bacnet/basic/service/h_cov.c
+++ b/src/bacnet/basic/service/h_cov.c
@@ -276,10 +276,11 @@ static int cov_encode_subscription(
  *  @return How many bytes were encoded in the buffer, or -2 if the response
  *          would not fit within the buffer.
  */
-/* Maximume length for an encoded COV subscription  - 27 bytes for BACNET IP6
- * 31 bytes for IPv4 (longest MAC) and lets round it up to the machine word
+/* Maximume length for an encoded COV subscription  - 31 bytes for BACNET IP6
+ * 35 bytes for IPv4 (longest MAC) with the maximum length
+ * of PID (5 bytes) and lets round it up to the 64bit machine word
  * alignment */
-#define MAX_COV_SUB_SIZE (32)
+#define MAX_COV_SUB_SIZE (40)
 int handler_cov_encode_subscriptions(uint8_t *apdu, int max_apdu)
 {
     if (apdu) {