Bosch B21CT80SNB Refrigerator: Ice Maker & Cooling Fixes

Bosch B21CT80SNB is a US-market black-finish 36-inch French-door bottom-freezer refrigerator with a chiller drawer and water/ice dispensing. Bosch identifies it as part of its 800 Series range; the exact Bosch product page and supporting specification sheet are linked below. Verify the full model number and any /01, /02 or other E-Nr revision from the rating plate before applying control instructions. A warning tone, a displayed temperature and a technician fault code are not the same thing. No model-specific alphanumeric error-code list was confirmed for this record, so none is presented as verified. Start with the external checks below and stop if you encounter water near electrics, smoke or damaged wiring.

Safe first checks

• Check that the appliance has power at its normal grounded outlet, and inspect the home circuit breaker without opening the appliance.
• Confirm the doors or freezer drawers close completely. Look for obstructions and visible gasket gaps, then follow the owner manual for cleaning.
• Check the selected temperature and keep visible air vents clear. Note whether cooling improves after normal operation; do not repeatedly cycle power.
• If ice output has changed, confirm the ice maker is switched on where the manual permits and check that the ice container is correctly seated. Do not pry into ice-maker mechanisms.
• If the unit has a water-fed ice maker or dispenser, inspect only accessible external water tubing for visible kinks or leaks. For leaks, shut off the supply and request service rather than opening internal plumbing.

Problems to identify before contacting service

• Filtered water is not dispensed: record the observed condition, check the manual-approved external items, and contact Bosch if it persists.
• Ice maker supply or ice output problem: record the observed condition, check the manual-approved external items, and contact Bosch if it persists.
• Freezer or fresh-food temperature too warm: record the observed condition, check the manual-approved external items, and contact Bosch if it persists.

What these controls and warnings mean

The B21CT family documentation includes both the SNB and SNS finish variants. Inspect the water supply and dispenser status without removing covers, and use the appropriate manual section for alarm and temperature settings. A filter warning should not be confused with a compressor failure.

No exact-model numeric or letter-code table is claimed here. The model may have alerts or service diagnostics; confirm any displayed characters against the applicable Bosch manual and installed E-Nr control version before drawing a conclusion.

Specifications and configuration

20.7 cu. ft. gross total capacity (Bosch 2018 design guide); 36-inch counter-depth refrigerator. Dual AirCool cooling; frost-free refrigerator with automatic freezer defrost. Black stainless finish, three-door French-door design, full-width chiller drawer, filtered water and ice dispenser, automatic ice maker.

When to stop troubleshooting

Stop using the appliance and arrange qualified service if wiring or the cord is damaged, there is smoke or a burning smell, or water reaches electrical parts. Do not remove electrical covers, enter a live cabinet, pierce refrigerant tubes or bypass safety devices.

Official manuals and model support

• Bosch official B21CT80SNB product page
• Bosch model specification reference
• Bosch support and E-Nr revision selector
• Bosch manufacturer owner / operating manual

For continuing faults, write down the complete E-Nr and FD serial designation and describe what you observed. Bosch customer support can identify the applicable control version and service options.