Help with these abbreviations?

[scattershot]

Sometime back, an HVAC tech checked our two-story system consisting of a gas heater and electric AC on each floor.

He left us some readings for the following:

L.P.
C.I.T.
E.I.T.
EOT

I've tried searching these terms online, but haven't come up with much yet.

Could anyone tell me what each of these stands for? Thanks in advance.