Hanna Instruments HI 4012 - Manual (Page 7)

7
•
Gas bubbles may form from solution out-gassing due
to temperature change. Gently tap body of sensor to
dislodge them from sensing membrane.
HI 4012
•
Remove protective cover from sensor tip.
HI 4112
•
Remove the protective plastic wrap that covers the
ceramic junction before assembling sensor for the first
time.
•
HI 7072 reference fill solution should be added daily
to electrolyte reservoir before electrode use.
•
During measurement always operate electrode with
the fill hole open.
•
During normal use, fill solution will slowly drain out
of the tapered cone junction at the lower portion of the
electrode. Excessive loss (>4 cm drop within 24 hours)
is not normal. If this occurs verify cap is tightened and
the interface between the internal cone and outer
body is free of debris.
•
Add fill solution daily to maintain a good head pres-
sure. For optimum response, this level should be main-
tained and not be allowed to drop more than 2-3 cm
(1-inch) below fill hole. Fill solution must cover the
ceramic found on the inner stem.
•
If an erratic measurement occurs, check to see if for-
eign matter is seen trapped near the internal cone.
Drain, wipe off outer cone while depressing cap, re-
lease cap and refill with fresh fill solution.