Diagnostic to determine cause of annunciator beeping and trouble signal labelled RTU3. Inspected systems and found no RTU's on the roof as labelled with #3 after further diagnostics it is likely caused by RTU #2 on the roof having no high voltage triggering a trouble signal in the Alarm panel. Pushed reset on the alarm panel but did not clear the trouble signal. Recommend contacting alarm company to clear trouble signal if no high voltage will be applied to RTU#2. While we were on the roof, RTU #6 was operating with extreme high levels of carbon monoxide (over 2000 PPM). The disconnect has been shut off and the unit should not be operated. Due to the age and condition, we recommend replacing RTU6.
