Section 4; Freezer Adjustment; Product Temperature Adjustment; Overrun Adjustment - Stoelting U421/U444 Owner's Manual

4.1 FREEZER ADJUSTMENT

This section is intended to provide maintenance person-
nel 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 (see Figure 26).
Figure 27. 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) for an overrun of 45 to 50%.

SECTION 4

MAINTENANCE INSTRUCTIONS
The mix pump that fills the left freezing cylinder of the U444
has been preset at the factory to produce a soft serve
product with approximately 40% overrun. The mix pump
that fills the right freezing cylinder of the U444 has been
preset at the factory to produce a shake product with
approximately 50% overrun. The left and right pumps on
the U421 have been preset to produce a soft serve 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 .
B. Remove the lower back panel from freezer.
C. On air compressor side of pump, locate the long/
Overrun Adjustment
D. The overrun setting is indicated by a pointed pin.
E. To adjust overrun, loosen the allenhead screw
21
slender piston rocking arm. The rocking arm down-
ward 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 (see
Figure 27).
Figure 28. Overrun Adjustment
(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).