Delta-T Devices AP4, User Manual

Page: 14 / 64

CALIBRATION
Page 14
STICK DOWN THE PAD
Place the damp filter paper on the back of the calibration plate to cover all the
calibration holes.
Seal down with sticky tape.
Trim loose tape from the edges. Smooth down the tape to remove any air pockets.
Return the calibration plate to its plastic zipper-lock bag until needed. This will slow
down the rate at which it dries out, and also keeps it clean.
In our experience, in the U.K.,
it has stayed damp for three days if kept in its bag.
Smooth down the tape to remove any air pockets.
Protect the plate from greasy fingers!
Leave for about 1 hour before
calibrating.