Respironics humidifier not heating up.

[jmz]

I had to get my respironics system one 550p sent off because it kept saying 'service required " . Got it back , they charged me 225 to replace the blower motor. Also when I got my cpap back from the provider , my water tank was missing . They charged me for a new one

Now the humidifier is not heating up The therapy symbol lights up but no heat ??????????????

[jmz]

Never mind I must have over filled the reservoir so it looked like it was not using any water when the level got down to the full mark. Plus I was not testing it right. I learned on youtube that the machine has to sense pressure for the heater to work