Hach 900 MAX manual 8 Replacing the Fuse, Motor/Gear Box, Internal Desiccant Module

Section 7

7.8 Replacing the Fuse

DANGER

For continued protection against fire, replace fuses with only fuses of specified type and current rating.

PELIGRO

Para una continua protección contra incendios, reemplace los fusibles únicamente por los del tipo y capacidad recomendados.

Medium Delay Fuse, 5 Amp

The main 12 volt line is fused as soon as it enters the controller housing. This is a 5-amp medium delay fuse (Cat. No. 8753) and is accessible from outside the case on the back side of the controller housing. To remove the fuse unscrew the cap on the fuse holder with a flat blade screwdriver.

PCB Fuse Removal and Inspection

Pull the fuse straight out of the holding clips to remove the fuse. The wire strand inside the glass tube will be broken. Use an ohmmeter to tell for sure if a fuse needs to be replaced.

7.9 Motor/Gear Box

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

7.10 Internal Desiccant Module

Note: The desiccant module cannot be recharged by heating. Do not attempt to bake the desiccant module in an oven to remove the moisture as this could be a fire hazard.

The Internal Desiccant Module (Cat. No. 8849) consists of a moisture-absorbent material inside a poly bag. If the humidity indicator on the front panel turns pink, replace the module and the back panel perimeter gasket (Cat. No. 8606). The desiccant module is located under the CPU board.

7.10.1 Replacing the Desiccant

To replace the desiccant, detach the controller from the refrigerator cabinet, and remove the screws from the controller bottom panel. Remove the desiccant bag and replace with a new one. Replace the controller gasket and cover plate. Reattach the controller to the refrigerator. 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. If the humidity indicator is blue the desiccant is dry. 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.

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8990mnt.fm	Replacing the Fuse