What is the purpose of the desiccant module?

The desiccant module is used to control humidity within the Indoor Furnishings, ensuring optimal performance.

How often should the memory battery be replaced?

The memory battery typically has a service life of five years and should be replaced when the warning "MEMORY POWER LOW" is displayed.

What is the function of the Internal Case Humidity Indicator?

The Internal Case Humidity Indicator signals whether the desiccant is dry or needs replacement based on its color, and provides guidance on inspection if the indicator turns pink or white.

Motor/Gear Box, Internal Case Humidity Indicator, Memory Battery

Section 5

1.	Desiccant module slides under circuit board		6.	J5	Distributor/Full Bottle Shut-off

2.	J8	LCD Display	7.	J2	12 V dc

3.	J6	Auxiliary	8.	J3	Fuse

4.	J1	Liquid Sensor	9.	J4	Motor

5.	Lithium Memory Battery		10.	J9	Keypad

5.10 Motor/Gear Box

The motor/gear box requires no regular maintenance. The special formulation gears are self lubricating and require no oil or grease.

5.11 Internal Case Humidity Indicator

After replacing the desiccant module and re-sealing the case, the Internal Case Humidity indicator disc (Cat. No. 2660) should return to its original blue color. Replace the indicator disc if it fails to return to blue after replacing the desiccant module. To replace the indicator disc, remove the bottom panel that is held in place by a small clip and screw.

5.12 Internal Case Humidity Indicator

The humidity indicator is located on the left front side of the controller. If the humidity indicator is blue, the desiccant is dry. If the indicator turns pink or white, inspect the electronics housing for seal failure and replace the desiccant module.

5.13 Memory Battery

Random Access Memory (RAM) is a very reliable data storage medium for microprocessor applications. However, RAM requires power at all times. If power is removed, the data stored in the RAM chip is lost. Therefore, you cannot power the RAM chips from the 900 Composite Sampler power supply because you would lose data and program settings every time you unplugged the power cord. A separate battery located inside the sampler controller is provided to power the RAM chips and the real-time clock. The memory battery keeps the program entries and logged sample data alive inside the RAM memory when the main power fails or is removed for transport or replacement.

The 900 Composite Sampler memory battery consists of a 1.5 V dc Lithium cell. The battery is soldered to the main circuit board.

Should the memory battery voltage fall too low to properly maintain the program settings, a warning: MEMORY POWER LOW will alert you to replace the battery. The 900 Composite Sampler utilizes a very small amount of energy from the memory battery during normal operation. The service life of the batteries in this application is typically five years.

Page 36

Motor/Gear Box

8544Maintenance.fm

Hach 900 manual Motor/Gear Box, Internal Case Humidity Indicator, Memory Battery, Section

Models: 900