Combustible gas readings, either negative or greater than 100% LEL, may indicate an explosive concentration of gas beyond the accurate response range of the combustible gas sensor. Pressurized or low pressure samples will give erroneous oxygen percent readings.
As early as 1981, Eddie Van Halen had written the keyboard part that would eventually become this song. David Lee Roth didn't like the idea of Eddie playing keyboards, and it wasn't until Eddie had built his own recording studio (5150) that he recorded the song with Ted Templeman during a late night recording session.
The video for Right Now shows Eddie Van Halen tickling the ivories. OK, so that's just the video -- maybe it's not EVH in the studio playing piano on the album. But Eddie is a classically-trained pianist (right?) -- maybe it is EVH and he records his guitar and piano parts separately for the studio albums.