Bunn Brewer STF-20

Use of a damp cloth rinsed in any mild, non-abrasive, liquid detergent for cleaning all surfaces on Bunn-O-Matic equipment

Check and clean the sprayhead. The sprayhead holes must always remain open

With the sprayhead removed, insert the deliming spring (provided) all the way into the sprayhead tube. When inserted properly, no more than two inches of spring should be visible. Saw back and forth five or six times

NOTE - In hard water areas, this may need to be done daily. It will help prevent liming problems in the brewer and takes less than a minute

Sign off on the daily brewer cleaning

Remove wires from control thermostat leads

Remove the thermostat capillary bulb by firmly pulling-up on the capillary at the tank lid

Remove the screws securing control thermostat bracket

Measure 4.5 inches above the bulb on the new capillary tube

Insert the capillary bulb through the hole in the tank lid and press the grommet firmly

Bend the capillary tube so that the tube and bulb inside the tank are in the vertical position

Ensure the capillary tube is clear of any electrical termination and not kinked

Secure the control thermostat inside the inspection panel

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 100 or 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

Locate the black wire on the control thermostat

Gently remove the capillary bulb and grommet from the tank

Check the voltage across the black wire of the control thermostat and the white insert on the two pole 100 or 120 volt or three pole 120/240 volt terminal block and the red insert on the two pole 200 volt or 240 volt terminal block with a voltmeter when the control thermostat is turned 'ON' (Fully clockwise). Connect the brewer to the power source.

NOTE: Do not remove or install wires while timer board is installed. Pressure applied to one side may cause damage to the board

Remove the two #6-32 screws securing circuit board to component mounting bracket

Remove circuit board and nylon spacers

Remove all wires from the timer

Attach all wires to the replacement timer board prior to installation to the component mounting bracket. Reconnect the wires

Install new circuit board with nylon spacers to component mounting bracket

NOTE: Check that the brewer is connected to water supply, the tank is properly filled, and a funnel and server are in place, prior to setting or modifying volumes

NOTE: All volume settings must be done with the sprayhead installed

Modifying brew volumes. To modify a brew volume, first check that the SET/LOCK switch is in the 'SET' position on the circuit board

NOTE: Do not remove or install wires while timer board is installed. Pressure applied to one side may cause damage to the board

Disconnect the brewer from the power source and remove the front panel

Voltage across terminals TL1 and TL2 when the 'ON/OFF' switch is in the 'ON' position

Voltage is present as described

If voltage is not present as described, check the brewer wiring harness

Voltage across terminals TL1 and TL4 when the 'ON/OFF' switch is in the 'ON' position

Voltage indication is zero volts

If voltage is not as described, disconnect the brewer from the power source and replace the timer