SECTION 4
MAINTENANCE INSTRUCTIONS
4.1 FREEZER ADJUSTMENT
This section is intended to provide maintenance personnel with a general understanding of the freezer adjust- ments. It is recommended that any adjustments in this section be made by a qualified person.
4.2 PRODUCT TEMPERATURE ADJUSTMENT
A potentiometer is used to control the product tempera- ture. To change the temperature of the product, follow the steps below:
A.Loosen the two screws under the header display sign, then pull sign out and down.
B.Use a screw driver to make desired adjustment. A label near the potentiometer will give complete in- structions. Figure 28.
The mix pump has been preset at the factory to produce a product with approximately 40% overrun. Because of differences in mix formulation, temperatures and barometric pressure, this figure may vary. It will be necessary for approximately 2 gallons (7,5 liters) of mix to be pumped thru the freezer before changes in the product are noticeable due to adjustments in overrun.
Overrun is controlled by the length of the air compressor piston stroke within the piston cylinder. Lengthening the stroke within the cylinder will increase overrun. Con- versely, shortening the stroke will decrease overrun. To perform an overrun adjustment, refer to the following procedure:
A. Turn the mix pump switch to the OFF position. Disconnect both power sources/circuit breakers.
B. Remove the lower back panel from freezer.
C. On air compressor side of pump, locate the long/ slender piston rocking arm. The rocking arm downward travel is limited by a stationery cam. On the face of the cam there is an overrun setting indicator plate numbered 3 thru 8 and an adjustment knob. Figure 29.
Figure 28. Potentiometer
4.3 OVERRUN ADJUSTMENT
The product when served is a combination of air and mix. Overrun is a measure of the amount of air blended into the mix.
Overrun can be expressed in terms of the amount of weight loss for a given volume. For example, if a pint of liquid mix weighs 18 ounces (510 grams) and a pint of frozen product with air added weighs 12 ounces (340 grams), the overrun is said to be 50 percent "18 oz. (510 grams) - 12 oz. (340 grams) = 6 oz. (170 grams)", (6 /12) x 100 = 50%.
The overrun can be checked by placing a one pint container on an ice cream scale and zeroing out the scale. Then fill a one pint container with frozen product. The container should be filled over the top and leveled with a straightedge. The product should not contain any air pockets. When weighed on an ice cream scale, one pint (473 milliliters) of product should weigh 12 to 13 ounces (340 to 368,5 grams).
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Overrun Adjustment
Figure 29. Overrun Adjustment
D. The overrun setting is indicated by a pointed pin.
E. To adjust overrun, loosen the allenhead screw (located within the center of the adjustment knob) with the 5/32" (4mm) allen wrench provided. Rotate the adjustment knob counterclockwise to a higher number for higher overrun, or clockwise to a lower number for lower overrun. Each number multiplied by 10 represents the overrun percentage (ie: #4 = 40% overrun).
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