ISCO 4230 - 5.2 Desiccators

4230 Flow Meter
Section 5 Maintenance and Service
5-2
spray any of the terminals (pins or jacks) inside the connectors;
residue from the sprays could cause intermittent or failed con-
nections.
5.2 Desiccators The 4230 has a reusable desiccant canister held by a steel clamp
on the inside of the case lid. There is also a tubular desiccant car-
tridge on the top of the case next to the connectors. The canister
contains silica gel that adsorbs moisture trapped inside the flow
meter's case when it is closed. This keeps the inside of the case
completely dry during shipment, storage and use. If you leave
the case open, the desiccant will quickly absorb moisture from
the surrounding air and will soon be saturated. It will no longer
be able to protect the flow meter. Both desiccators use a color
indicator that changes from blue to pink when saturated. The
external desiccant cartridge vents the reference port of the
pressure transducer and the air intake port for the bubbler
system air pump.
5.2.1 Regenerating the
Internal Case
Desiccant
Look at the desiccant canister each time you open the case. The
canister has a window on its side that appears blue when the
desiccant is dry. As the desiccant absorbs moisture, the window
will turn pale pink or amber. When the window is pink, you need
to regenerate the desiccant, or replace it with the spare canister
provided in the flow meter accessory package. Remove the can-
ister from the flow meter by pulling outward on the spring clamp,
releasing its hold on the canister.
Remove the canister and heat it in a vented oven in a well-venti-
lated room at 300°F (150°C) for about three hours, or until the
blue color returns. Do not use a microwave oven; the metal
case of the canister could cause arcing. After cooling, reinstall
the canister in the flow meter. Make sure the window on the side
of the canister remains visible.
Figure 5-1 Location of the Case Desiccating Canister