LX40C

Overview

The Hobart LX40C is a fully automatic, front-loading dishwasher in the Hobart LX Series. It is identified in the installation and operation manual as model LX40C, manual number ML-104355. The C designation identifies it as a low-temperature chemical-sanitizing model. It washes and rinses with fresh water, and the manual specifies sodium hypochlorite solution (bleach) as its sanitizing agent.

The LX Series has electronic controls, a pumped drain, a fill hose and a drain hose. The manual lists two 20" x 20" racks as standard equipment. All LX Series dishwashers shut down automatically four hours after their last use. The LX40C’s control settings include programmable wash and chemical functions; see the specifications and operation sections for the listed recommended settings.

Key Features

• Low-temperature chemical sanitizing: The LX40C uses 5.25% or 8.40% sodium hypochlorite solution as its sanitizing agent.
• Fresh-water rinse: The LX30C and LX40C model description specifies a fresh-water rinse.
• Automatic operation: The LX Series is described as fully automatic and front-loading.
• Pumped drain: A pumped drain is included in the LX Series standard equipment listed in the manual.
• Electronic controls: Electronic controls are listed as standard equipment.
• Automatic shutdown: The machine shuts down four hours after last use.

Specifications

• Manufacturer: Hobart Corporation.
• Model: LX40C.
• Manual model number: ML-104355.
• Product type: Fully automatic, front-loading commercial dishwasher.
• Motor: 3/4 horsepower electric motor, stated for the LX Series.
• Standard racks: Two racks, each 20" x 20", stated for the LX Series.
• Controls and drainage: Electronic controls and pumped drain.
• Hoses: Fill hose and drain hose are listed as standard LX Series equipment.
• Sanitizing type: Low-temperature chemical sanitizing.
• Sanitizer: 5.25% or 8.40% sodium hypochlorite solution (bleach).
• Rinse: Fresh-water rinse.
• Water use: 1.2 gallons per rack for LX30 and LX40 models. The manual lists 2.2 gallons per rack for the extended rinse cycle, available on LX40 models in the heavy wash cycle only.
• Incoming water temperature: 140 °F minimum for LX40C.
• Flowing water pressure: 15–25 psig for LX40C. The manual requires a pressure-reducing valve if pressure exceeds 25 psig and warns that pressure below 15 psig may cause improper operation.
• Recommended water hardness: 4–6 grains per gallon.
• Chlorides: Must not exceed 50 parts per million.
• Automatic idle shutdown: Four hours after last use; the LX40C programming chart also lists four hours as the recommended idle-shutdown setting.
• Programmable LX40C settings: The manual’s LX40H/LX40C chart gives a C-model wash setpoint range of 130–150 °F, with 130 °F recommended. The LX40C sanitizer duty cycle is adjustable from OFF to 1–10, with 40% recommended. Detergent on time is adjustable from OFF to 30 seconds, with 7 seconds recommended. Rinse-agent duty cycle is adjustable from OFF to 1–10, with 70% recommended.
• Other LX40C programming values: Cycle selection can be locked or unlocked, with unlocked recommended; default cycle can be Light, Normal or Heavy, with Light recommended. The delime counter preset can be OFF or 500–3000 cycles, with 1500 cycles listed as the factory setting and the manual noting that the setting is determined by water condition.
• Priming and heavy-cycle settings: Detergent, rinse-agent and sanitizer prime times are adjustable from 25–75 seconds, with 35 seconds recommended for each when the applicable pump is on. Heavy wash time is adjustable from 100–200 seconds, with 156 seconds recommended. Heavy rinse options are Normal at 10 seconds or Extended at 20 seconds.

Installation & Requirements

Before installation, check the dishwasher for shipping damage and verify that the electrical supply agrees with the machine data plate. Plumbing connections must comply with applicable sanitary, safety and plumbing codes. Electrical and grounding connections must comply with the applicable portions of the National Electrical Code and/or other local electrical codes. The supplied material does not state the LX40C’s electrical rating, so use the machine data plate for that information.

Water supply

The LX40C requires incoming water at a minimum of 140 °F and flowing pressure of 15–25 psig. A pressure-reducing valve must be installed if flowing pressure exceeds 25 psig; the manual cautions that the regulator must have a relief bypass. Pressure below 15 psig may result in improper machine operation. The manual also calls for a manual shutoff valve upstream of the fill hose and recommends a line strainer between that valve and the machine connection. A water hammer arrestor meeting ASSE-1010 or equivalent should be installed in the common water supply line; the manual notes that it is supplied by others.

Make the water connection with copper piping at least 1/2 inch outside diameter; 3/4 inch is recommended. The manual specifies a 3/4-inch male garden-hose-thread connection at the machine. Water lines must be thoroughly flushed before connection to remove debris such as pipe chips, joint compound or solder particles, which may lodge in plumbing components. The manufacturer does not accept responsibility for fouling caused by foreign matter left in the lines.

Water quality affects warewashing performance and equipment life. Hobart recommends hardness of 4–6 grains per gallon and chlorides no higher than 50 parts per million. The manual advises treating water above 6 grains per gallon with a conditioner such as a softener or in-line treatment. Water below 4 grains per gallon also requires treatment to reduce potential corrosion. Sediment, silica, chlorides or other dissolved solids may call for particulate filtration or reverse osmosis. Consult the local water supplier about local water characteristics; the manual advises contacting a Hobart Service Office for specific treatment recommendations.

Drain and location

A drain hose is supplied with a 3/4-inch pipe connection adapter. It should be securely plumbed into the sink drain without kinking the hose. The drain must have a minimum flow capacity of 10 gallons per minute. Steam may escape from the door during normal operation. The manual says wood, laminates and veneers are unsuitable for surfaces exposed to dishwasher steam and detergents, and recommends stainless steel or other moisture-resistant shields for adjacent surfaces and the top.

The machine must be level to operate properly. The manual directs installers to level it front-to-back and side-to-side using a carpenter’s level placed diagonally on the rack tracks and to adjust the feet before making connections. After leveling, cover exposed adjustable-foot threads with the supplied black rubber tubing.

Operation

Before first use, clean the machine as directed in the manual. Confirm that the coarse and fine strainers are in place and free of debris, and check that the wash arms and, for the LX40C, rinse arms can turn freely. Follow the control instructions for the LX40H and LX40C in the machine manual. The manual’s LX40C programming chart lists a 130 °F recommended wash setpoint and a 40% recommended sanitizer duty cycle. It also lists a 7-second detergent on time and 70% rinse-agent duty cycle as recommended settings.

For the sanitizer supply, remove the sanitizer bottle cap and put the white delivery tube into the container, with the standpipe pushed to the bottom. Check that the tube is not kinked or obstructed and frequently check the clear portion of the chemical feed standpipe to confirm that sanitizer remains available. On the LX40C, use the prime cycle described under Operator Programming in the manual to initially charge the sanitizer delivery system. The LX40C programming chart lists 35 seconds as the recommended sanitizer prime time when the pump is on.

Important chemical warning: Never premix a wetting agent with sanitizing solution; the manual warns that hazardous gas may form. Chemical-sanitizing models should not be used to wash pewter, aluminum or silver, because sodium hypochlorite attacks these items. Follow the chemical manufacturer’s concentration instructions; do not exceed its recommended levels for detergent, sanitizer, rinse aid or lime-scale remover.

Cleaning & Maintenance

Clean the machine at least once each working day. At the end of the day, the manual directs operators to thoroughly clean, rinse and dry it, leaving the door open. Use only products formulated to be safe on stainless steel. Do not use steel wool, residential dishwasher detergent or abrasive or harsh cleaners on the control keypad and display. Do not allow food soil to collect on the tank bottom or foreign objects—especially metallic contaminants—to enter the machine.

1. Press OFF. The machine drains. When the display is no longer lit, open the door and remove debris from the bottom of the tank.
2. For the LX40C, remove the lower rinse arm by unscrewing the knurled knob, then pull the lower wash arm off its shaft. Remove the upper rinse and wash arms in the same manner. Remove the coarse and fine strainers and thoroughly clean these parts in a sink.
3. Wipe the machine interior, water-level probes and the probe under the fine strainer with a damp cloth. Wipe the exterior and the lip at the bottom of the inside of the door. Remove remaining debris with a mild stainless-steel cleanser and a soft cloth or brush. Do not use steel wool.
4. Replace the coarse and fine strainers. Push the lower wash arm onto its shaft, place the lower rinse arm on the shaft and tighten the knurled knob. Spin the arms to confirm they turn freely, then repeat for the upper wash and rinse arms.
5. Clean the control keypad and display with a soft damp cloth or sponge and mild cleanser. Leave the door ajar overnight so the interior can air out and dry.

Do not over-soften the water: the manual recommends hardness no lower than 4 grains per gallon. Follow the chemical professional’s prescribed deliming schedule. Deliming solution, rinse agents or other acids must not contact bleach or rinse solution containing bleach in chemical-sanitizing machines, because mixing may create hazardous gas. Do not leave deliming agent in the machine longer than its manufacturer recommends. The pump motor has permanently sealed bearings and requires no lubrication. Failure to follow use, care and maintenance instructions may void the Hobart warewasher warranty.

Troubleshooting

• No operation and no display: Check whether the machine is off, whether a fuse is blown or a circuit breaker is off, and, on corded models, whether the cord is plugged in.
• No operation with a display: If the display indicates that the door is open, open and close the door. If the problem persists, the manual directs the operator to contact a local Hobart Service Office.
• Dishes are not clean: Check for clogged strainers restricting water to the pump, obstructed wash arms or arms that will not turn, and rinse arms that will not turn. A clogged detergent dispenser is another possible cause. The manual also advises scraping dishes before loading.
• Low temperature readings: Check that the incoming water meets the recommended temperature. Rapid cycle use, a heavy ware load that cools the wash water, or a low heater setpoint may contribute to low readings. Do not overload racks. The manual’s instructions for heater adjustment differ by model; refer to its LX40C controls and programming instructions.
• Machine will not fill or will not fill high enough: Check for a clogged hose strainer and confirm that site water pressure meets the minimum. Make sure the water-level probes are clean and that the main water supply valves are working. The manual also lists an open drain valve as a possible cause.
• LX40 display reports a drain or fill problem: The manual lists “DR1 PRBLM,” “FILL1 PRBLM,” “FILL2 PRBLM” and “FILL3 PRBLM” among LX40 diagnostic messages. For a suspected drain-valve obstruction, it describes turning the machine OFF to drain, turning it ON and repeating twice, then waiting for READY and pressing WASH. It then directs the operator to compare the water level before and after a 30-second interval with the door closed. Repeat the OFF–ON procedure if the level changes; contact a local Hobart Service Office if the issue persists.

Applications

The LX40C is suited to commercial dishroom work where a front-loading machine with a fresh-water rinse and chemical sanitizing is required. Its specified sanitizer is sodium hypochlorite solution, so ware must be compatible with bleach: the manual specifically warns against washing pewter, aluminum and silver in chemical-sanitizing machines. The included rack size and rack-use water figures are stated in the specifications above; the manual does not provide a production rate or a dishes-per-hour figure.