Why isnt my climate air tubing warming on manual setting?

[Pgw]

I have been using Resmed cpap machines for 7 years. My first machine lasted 3 years before the heated tubing just quit heating. I get a roaring headache from cold air even with a low pressure setting of 6. I have to have manual tube temp on 85-86 and humidity on at least 5. The last 3 years I have had to swap out 4 machines due to this issue. The last machine I had was air sense 11, constantly rained out because tube never warmed and humidity had to be on 8. They finally agreed to send a resmed 10. Worked great first 2 nights. Tubing heated right up and lasted all night. 3rd night quit, same story. Air stopped warming and awoke with headache. I have spoken with technicians at resmed and have gone many rounds with provider. Has anyone else had these same issues? Is it a software or electrical issue? I have taken old hoses and tried them as well as new and they don't warm. I've tried switching outlets throughout the house just to see if that was cause.
Am desperate for a remedy.