Superheat test

Hello all,

Recently, I made a superheat test for steam, and I get some “strange” results (in my opinion).

Steam Pressure was(T1 / T2 / T3): 2.9 / 2.0 / 2.4 bar
Temperature of steam was (Test1 / Test2 / Test3): 135.8 / 126.7 / 130.6 degree
Temperature in expansion tube: 96.2 / 96.2 / 96.2 degree
Boiling point: 100 degree

From thows parameters I obtained negative superheat (-3.8 degree)

My questions are:

  1. Is normal to obtain negative superheat?
  2. regardless of steam pressure, values were the same (96.2)

Dryness test was OK (I obtain 0.98 / 0.97 and 9.95).

Best regards,