My moms unit was replaced and I have noticed that she started complaining about headaches since the change. I suspect the unit is outputting bad quality air but have no proof. I confirmed that when she complaints about headache and I retrieve the canula she stops complaining. She is COPD, astmatic and has pulmonary hipertension. She saturates between 89 and 92 without the concentrator. At 1.5 l per min she stays between 96 and 98. Could the concentrator be outputting a gas mix causing her the headache. I also notice that the canula line acumulates condensation and that was not a problem with the previous unit. Any thoughts or advice?