Xylem DH-21 - Manual (Page 16)

2-4 Installation
DH-21
Figure 2-2. RS-232 Cable
2.3 Accessing the Battery Pack and Desiccant
The “ W
ATER LOG” uses a factory assembled 7.2-Volt, 13.5 Amp Hour “D” cell lithium battery
pack. The battery can operate the “ W ATER LOG” for a period of up to 5 years, logging once per
day. Logging on 15-minute intervals shortens battery life to 3 years. Likewise, more frequent
intervals will shorten battery life even more. A battery voltage measurement is logged on each
measurement giving you a record of the rate of discharge and an up-to-date battery voltage.
To access the battery pack, you must remove the well head assembly from the well. Be careful
not to kink or damage the vented cable when installing or removing the “
W
ATER LOG”. Figure
2-3 shows outlined features of the well head assembly.
The battery compartment is accessed by unscrewing the upper and lower sections of the well
head package at the separation joint. Gently pull the Circuit Board/Dry Air Assembly (2) from
the lower section. Locate the wires from the battery and connect/disconnect the battery
connector.
To remove the Battery Pack (4), disconnect the battery connector, remove the desiccant packs
and pull the battery out. A new battery can be installed by following the above instructions in
reverse.
The well head assembly also contains a Desiccant Cartridge (1). It is designed to protect the
sensor from moisture accumulation. The Desiccant Cartridge (1) and the Desiccant Packs (3)
inside the dry air system should be checked every 3 to 6 months. The Desiccant Packs have a
transparent strip which allows the condition of the desiccant to be visually checked. Dry
desiccant is dark blue and saturated desiccant will have turned pink. The Desiccant Packs and