6.10 Basic Dishwasher Hook-ups

Commercial

Hot water hook-up only, except for some large units that may have large scrapper section.

• Building hot water supply is often 140 degrees F. Flow pressure should be not less than 15 to 20 PSI and static pressure should not be less than 40 PSI unless specified by the manufacturer.
• Units generally have a 1/2” or 3/4” line connection. Line strainers are provided with most machines, some are shipped in the inside of the units, and some are attached to the water line. They should be installed on the incoming line in the proper location and water must flow in the direction of the arrows and the clean out plug on the strainer must point down.
• Some larger machines come pre-plumbed to facilitate fast installations for replacement machines, common drains, water, and steam. Most have 2” gravity drains.

Trouble shooting:

Low water temperature causes problems with booster heater and may not allow plate scraps to dissolve properly. Low pressure is also bad as timed fill cycles do not allow enough water in during the cycle to wash properly, glasses may not rinse properly.

Excessive pressure is also bad as solenoids wear out and water hammer also causes problems. All lines should be flushed out after soldering to protect the solenoid valves.

Some machines have just the rinse water connection (180 degrees) and others have two connections, one 140 for the wash cycle and another 180 degrees from a booster heater.

Boosters are required when final rinse temperatures are not available for 180 degrees. The dishwasher could have either an electric booster or a steam booster or exchanger. Both usually have all extra equipment required such as, PR valves, gauges, pressure relief valve, line strainers, gauges and line-up instructions. Install booster tanks so that the removable end door is on the outside. Vacuum breakers (approved for hot water) are also included for anti-siphonage.

Hard water also causes problems solenoids, rinse jets, wash arms and rinse arms clog up with deposits, also electric heaters have problems and burn out. With the exception of the under-counter type of unit, all dishwashers operate on the principal of re-circulated water which cuts down on water consumption. The water is replenished by the rinse water only or a bleeder valve on large units.

Most machines have installation instructions, and all connections are tagged, like 140 degrees fill and 180 degree rinse, etc.