Maintenance And Adjustments; Overrun Adjustment; Mix Pump Hose Reposition - Stoelting U431 I2 Owner's/Operator's Manual

This section is intended to provide maintenance personnel
with a general understanding of the machine adjustments.
It is recommended that any adjustments in this section
be made by a qualifi ed person.
4.1

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 and a pint of frozen product
with air added weighs 12 ounces, the overrun is said to
be 50 percent: 18 oz. - 12 oz. = 6 oz., (6/12) x 100 = 50%
The overrun can be checked by placing a one pint con-
tainer on an ice cream scale and zeroing out the scale.
Then fi ll a one pint container with frozen product. The
container should be fi lled 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
of product should weigh 12 to 13 ounces.
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 baro-
metric pressure, this fi gure may vary. It will be necessary
for approximately 2 gallons of mix to be pumped through
the machine before overrun changes in the product are
noticeable.
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. Conversely,
shortening the stroke will decrease overrun. To perform
an overrun adjustment, refer to the following procedure:
Overrun
Adjustment
Knob
Figure 4-1 Overrun Adjustment
A. Press the Pump button to turn the pump power
Off. Disconnect power sources/circuit breakers.
B. Remove the back panel from the machine.
Owner's Manual #513660
SECTION 4

MAINTENANCE AND ADJUSTMENTS

C. On the air compressor side of the 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 through 8 and
an adjustment knob (Fig. 4-1).
D. The overrun setting is indicated by a pin.
E. To adjust overrun, loosen the allen-head screw
(located within the center of the adjustment knob)
with the 5/32" 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 approximately represents the
overrun percentage (i.e. setting 4 = 40% overrun).
F. Tighten the allen screw, then place the wrench
back in its clip. Replace the lower back panel
and secure with the four screws. Press the Pump
button to turn the pump power On.
4.2

MIX PUMP HOSE REPOSITION

Mix pump hose must be repositioned every 800 gallons
of mix pumped or every 2 weeks. Failure to reposition
the hose will result in reduced mix pump liquid capacity,
dispense stoppage, popping, and possible mix pump hose
leakage. Follow the steps below to reposition the hose:
A. Run cleaning solution through pump.
B. Turn the pump off and relieve any pressure by
opening the spigot.
C. Grasp the pickup hose end of the mix pump hose
with one hand and turn the pump on. Pull down
on the pickup hose end until 12 to 14 inches of
tubing has fed through the pump then turn the
pump off (Fig. 4-2).
D. Loosen the small clamp at the pick-up hose
adapter and disconnect the mix pump hose.
E. Cut 7-1/2 inches off the end of the mix pump
hose.
F. Reconnect the mix pump hose to the adapter.
G. Continue normal operation. Mix hose will
automatically reposition itself with the adapter
near the black cover.
Each hose is long enough for 3 repositions before
replacement is required.
The hose timer must be reset each time the hose is
repositioned or replaced to keep an accurate record
of the hose service time.
17
NOTE
NOTE
U431 I2 Model Machines