Service manual

COMMON SERVICE PROBLEMS
ADS BULLETIN #02-44
Effective Date 8/94
Rack travel and counting with a timer in CONVEYORS
Rack-style conveyors move dishracks across the sprays by the reciprocation of articulating dogs. These
dogs push in one direction and fold down in the return direction. They push against the “ladder” on the
underside of the dishracks. The “speed” of NSF listed conveyor dishmachines is determined by the length
of time required for a Metro G-88 glassrack to travel across from the soil table to the clean table. The
starting and ending point is the table lip. The indicating point is the trailing edge of the rack. If it takes 36
seconds to cross this distance the rated speed will be 6 feet per minute.
The speed is determined by two items: the action of the conveyor dogs and the placement of bars on the
rack ladder. If either of these are missing or damaged the speed will drop. If too many ladder bars are
missing the rack will not travel through the machine. In actuality, the rack is responsible for 50% of the
conveyor’s speed mechanism. Racks other than the Metro G-88 glass rack will cause some variations in
the speed. The ADC-44 uses ten dogs to reduce this variation and give more consistent output.
If a clock timer is installed to act as a rack counter it can only record the amount of time the machine is
operational. It can not sense an actual rack. It can, however, accurately record the amount of time the
machine uses chemicals and energy. By estimating the number of potential racks the conveyor is capable
of processing you can arrive at an approximation. Fortunately, the ADC design operates only when a rack
is present and shuts down mechanically when the rack exits. This will give closer rack fi gures then other
styles of conveyor control devices. If there is an inaccuracy in the overall count, it will be less actual racks
washed then the multiplied fi gure. Note: while the actual rack count may be less, the amount of chemicals,
water and energy (over time) will be correct.
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