Champion usn-72 ユーザーガイド

Part 5: BASIC SERVICE

 To adjust the final rinse thermostat:  Turn power off to the dishwasher at the dishwasher control

cabinet.  Block the final rinse activator so the final rinse runs constantly.  Return the dishwasher to

normal operation.  Remove the protective cap from the center of the final rinse thermostat enclosure

to expose the adjusting screw.  Turn the adjusting screw incrementally 1/16 of a turn clockwise to

increase the final rinse temperature.  Turn the screw counterclockwise to reduce the final rinse

temperature.  Monitor the final temperature thermometer after each adjustment until temperature

maintains a minimum of 182-185

°

F.

°

To adjust the low temperature cutoff thermostat:   First perform the final rinse thermostat procedure

described above. Turn the steam supply off to the booster assembly so the final rinse temperature falls

below 180

°

F.  Remove the protective cap from the center of the cutoff thermostat enclosure to expose the

adjusting screw.  Turn the adjusting screw incrementally 1/16 of a turn clockwise to increase the cutoff

temperature.  Turn the screw counterclockwise to reduce the cutoff temperature.  In other words, if the

final rinse water temperature is 182

°

F. and the low cutoff thermostat activated the chemical sanitizing

system (supplied by others), then it would be necessary to turn the screw counterclockwise to reduce

the cutoff temperature to  178-180

°

F.

To replace the final rinse or cutoff thermostat:  Turn off the water and steam supplies to the booster.

Place a rack in the dishwasher to operate the final rinse and bleed off any water pressure from the line.

Turn power off to the dishwasher at the dishwasher control.  Remove the protective cap and round cover

from the thermostat body.  Note the location of the wires and disconnect.  Disconnect the conduit.

Remove the thermostat from the booster piping.  Install the replacement in reverse order.  Return the

dishwasher to normal operation and perform the adjustment procedures described above.

For machines S/N J1698 and after: To replace the control thermostat see the Special Bulletin Section

on page 111 at the end of this manual for instructions on the replacement of the thermostat.

The USN-72 dishwasher uses  a 3/4" steam solenoid valve on each tank

steam supply line. The 3/4" steam valves are identical in appearance to the

3/4" water valves, (See 5.3.4).  The steam booster uses a 1" steam solenoid

valve on the inlet of the booster steam supply line, (See picture at right).

  The 3/4" valves are controlled by a tank heat thermostat, (See 5.3.8), which

connects 120VAC to the valve coil during a call for heat.  If the valve fails to

operate, first check that 120VAC is supplied to the valve coil.  If voltage is not

present, then refer to the electrical schematic and troubleshoot the circuit.  If

voltage is present then the valve may require a rebuild kit or replacement coil.

Turn off power at the dishwasher power switch and main disconnect. Turn off

main incoming steam supply and bleed off any steam pressure in the line.  Check the coil for continuity

with a VOM set at the highest resistance range. If the coil checks good then disassemble the valve by

unscrewing the threaded bonnet with a strap or spanner wrench.  Remove and inspect the valve piston and

diaphragm.  Inspect the valve seat for mineral deposits and pitting.  (Replace the complete valve assembly

if pitting is severe).  Reassemble the valve in reverse order.  Turn on steam and power supplies and check

for leaks.