I HAVE BEEN HAVING PROBLEMS WITH THE EXPIRATORY CASSETTE ON MY SERVO I VENTS. I WAS WONDERING IF ANYONE ELSE HAS BEEN HAVING ANY PROBLEMS WITH THESE VENTS. I HAVE THEM SET UP WITH THE HUMID HEAT HMES. THE PROBLEM I AM HAVING IS THE VENTS WILL NOT ALLOW THE PT TO EXHALE. THIS HAS HAPPENED THREE TIMES. I HAVE BEEN USING THE SERVO I FOR ONE YEAR AND LOVE THESE VENTS EXCEPT FOR THIS PROBLEM. ANY HELP WOULD BE MUCH APPRECIATED.THANKS TO EVERYONE.JOSEPH