Bunn LCR-3 - Manual (Page 25)

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Field Calibration of the Concentrate Pumps / Dispenser Flow Rates
The factory set Default Values for the Pump & Dispenser Flow Rates are very accurate and typically do not
need to be field calibrated. However, if the mix ratio accuracy is ever in question, this procedure can be used to
recalibrate the unit in the field. Equipment Required:
250 ml graduated cylinder, with 2 ml graduations. BUNN # 34028.0000
2000 ml graduated container. BUNN # 34843.0001
NOTE: You can calibrate either the Concentrate Pumps or the Dispenser Flow Rate independently. Simply scroll
through the menu screen to the desired section and perform only those steps.
Calibrating the Left Concentrate Pump
1. Select PRIME on the Function Selector Switch. (refer to Priming the Concentrate Lines).
2. Place a container under the Dispense Tip and prime the concentrate lines until a steady stream of concentrate
comes out the tip (approximately 10 seconds).
3. Stop the Priming and allow the tip to stop dripping. Discard the concentrate collected.
4. Select NORMAL on the Function Selector Switch.
5. Locate the programming module and use the Arrow Down key to scroll through LCD screens until CAL LEFT
SIDE appears and press the YES button.
6. The CAL LEFT PUMP menu screen will be displayed. Place a 50 ml graduated cylinder under Dispense Tip and
activate the Left dispenser momentarily. The dispenser will run the Left Concentrate Pump for 20 seconds
and then shut OFF automatically.
7. Keep the graduated cylinder under dispense tip until all the concentrate has dripped out.
8. Measure the volume of concentrate collected in the graduated cylinder. The acceptable range for the volume
collected for the 1/4” tubing is 50-60 ml.
9. If the amount collected is not within the acceptable range, empty the graduated cylinder and repeat STEPS
6 – 8.
10. If the amount collected is still not within range, replace the pump tubing with a new Tube Kit, (refer to the
Tube Replacement Instructions).
11. When satisfied with the volume of concentrate collected, scroll down to the next menu screen.
12. The CAL LF PUMP VOL menu screen will be displayed. Use the (-) / (+) keys to adjust number displayed to
the amount measured in STEP 8.
Repeat steps 2-11 to Calibrate the Middle and Right Pumps
Dispenser Flow Rate Calibration
1. Press the Right hidden switch to display the ? WTR FLO menu screen.
2. Place a 2000 ml graduated container under Dispense Tip and press Left Dispense Switch momentarily. The
dispenser will dispense water for 10 seconds and then shut OFF automatically.
3. Keep the graduated container under dispense tip until all the water stops dripping.
4. Measure the volume of water collected in the graduated container. The acceptable range for the volume
collected is 1600 to 2000 mL.
5. If the amount collected is not within the acceptable range, empty the graduated container and repeat STEPS
1 -4.
6. If the amount collected is still not within range, inspect the dispense valves, tubing and mix chamber for lime,
kinks or other obstructions.
7. When satisfied with the volume of concentrate collected, scroll down to the next menu screen.
8. The CAL WTR VOL screen will be displayed. Use the (-) / (+) keys to adjust number displayed to the amount
measured in STEP 4.
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