Bunn Coffee Machine CWTF35-APS, GF

Warning: Disconnect the brewer from the power source before starting the test

Brewer disconnected from the power source

Blue and black wires disconnected from the limit thermostat

Continuity across the limit thermostat terminals checked with a ohmmeter

Sign off on the limit thermostat test

Disconnect the water supply tube from the fill basin

Remove the tank inlet fitting securing the fill basin to the tank lid, remove fill basin and tank inlet gasket. Set all three parts aside for reassembly

On brewers with faucet shut-off water supply to the brewer and disconnect the inlet and outlet water lines to the faucet coil assembly

Disconnect the black wire on the limit thermostat from the tank heater switch. On late model brewers also disconnect the blue wire from the limit thermostat to the control thermostat

Disconnect the black wire and the white or red wire from the tank heater terminals

Remove sprayhead and the hex nut securing the sprayhead tube to the hood. Set aside for reassembly

Remove the eight #8-32 nuts securing the tank lid to the tank

Remove the tank lid with limit thermostat, sprayhead tube, tank heater, coil assembly and control thermostat w/bracket (early models only)

Remove the two hex nuts securing the tank heater to the tank lid. Remove tank heater with gaskets and discard

Disconnect the brewer from the power source

Locate the blue wire on the control thermostat

Check the voltage across the blue wire on the control thermostat and the white insert on two pole 120 volt terminal block or three pole 120/ 240 volt terminal blocks and the red insert on two wire 200 volt or 240 volt terminal block with a voltmeter

Connect the brewer to the power source

Disconnect the brewer from the power source

If voltage is present as described, proceed to #5

If voltage is not present as described, refer to the wiring diagrams and check the brewer wiring harness

Locate the black wire on the control thermostat

Shut-off and disconnect the incoming water supply to the brewer

On automatic brewers gently remove the fill tube from back of fill basin

Remove the tank inlet fitting securing fill basin the tank lid. Remove fill basin and gasket. Set all three parts aside for reassembly

On brewers with faucets, disconnect the water supply to coil assembly and remove the tube from the tank to the faucet

Remove sprayhead and hex nut securing sprayhead tube to the hood. Set aside for reassembly

Disconnect the wires on the limit thermostat and the tank heater and the control thermostat (early models)

Gently pull the thermostat sensor and grommet from the tank lid

Insert a tube to the bottom of the tank and syphon ALL of the water out. (BUNN-O-MATIC has #12440 syphon assembly available for this purpose)

Gently reinstall the thermostat sensor and grommet in the tank lid

Warning: Disconnect the brewer from the power supply before starting the test

Voltage across the black and white wires on 120 volt models or the black and red wires for 120/240 volt models, 200 volt models and 230 volt models with a voltmeter

If voltage is not present as described, check wiring harness

Disconnect the black wire and the white or red wire from the tank heater terminals

Check for continuity across the tank heater terminals

If continuity is not present as described, replace the tank heater

NOTE- If the tank heater remains unable to heat, remove and inspect heater for cracks in the sheath

Sign off on the tank heater test