Columbia and Montour use the East Central Emergency Network on the PA-STARNet system transmitting off the ECEN Simulcast tower in Columbia County. There are 11 Fire channels listed, non as the primary, but 3 are sent to the Calls system so would think one of those is the main channel.
On the list I have seen, the channels names were displayed like this: EC F1, EC F2...EC F11. F1 or "Fire 1" is the main channel. Don't know if they changed that or not.
That sounds to me like you were looking at a radio capable of operating on Northumberland County's system, hence "NC Fire". Their main fire talkgroup is referred to as "Fire Primary".
I did a quick look around and did not find a station with an Engine 20 in Columbia, Montour, or Northumberland. So, without knowing more, I can't really come up with anything else.