Rice Lake Combination System - Precision Loads On-Board Weighing Systems - Manual (Page 58)

54 Precision Loads On-Board Weighing Installation & Service Manual
5.8 Lift-to-Weigh Program
When servicing on-board systems that have Lift-to-Weigh program as part of the PL9700 indicator, the following
guidelines are recommended:
• Always verify the system functions with the body elevated (Test numbers, Cal Factor etc.). Elevation should
be only a few inches off the truck chassis.
• Verify all L-1, L-2 and L-3 dimensions entered into the Setup Menu. If these numbers have been changed,
the calibration function will not be correct. The algorithm which calculates axle weights is dependent on
correctly-entered dimensional values.
• The Lift-to-Weigh calibration sequence always requires the Empty and Full calibration entries to be entered
twice consecutively.
Figure 5-4. Lift-to-Weigh Truck
5.8.1 Air Pressure Transducers
There are very few service issues relating to air transducer units after initial installation. For the system to operate
accurately and reliably, all pressure connections must always be leak-free. If the system shows signs of unstable
weight readings and large errors under load, all pressure connections must be checked immediately.
Note
Do not allow the female transducer adapter fitting to rotate when tightening air line fittings.
Use a 3/4" open end/box end wrench to hold the female transducer adapter fitting in place while using a 9/16"
open/box end wrench to tighten the air line fitting. When connecting air hose to the push-on air line fitting, make
sure the hose is clean and free from paint. See “Air Pressure Transducer” on page 11.
More typical problems with air transducer systems involve old or sticking leveling valves that do not respond
properly to loaded weights, or are affected by air leaks. The correct service repair in these cases are replacement of
the leveling valve itself. Rice Lake Weighing Systems recommends the Immediate Response Valve (part nr.
905-54-241) manufactured by Haldex, which is available from Rice Lake Weighing Systems. Diagnosis of this
problem is unstable weight readings, large loading errors, or errors which occur while loading but normalize when
the vehicle moves or is on level ground.
In very cold climate conditions (sub-freezing), it is possible that moisture exists in the air tank or air lines which,
when frozen, will affect the performance of the air transducer. If this occurs, the air tank must be bled in a warm
environment. Contact the local truck/trailer equipment supplier for anti-freeze products that can be used in the air
system.