Installation, Maintenance & Troubleshooting Flashcards

When troubleshooting a residential RO system with very slow tank fill time, which component should be checked last?

Answer: The household water meter

The water meter does not affect RO fill rate; feed pressure, pre-filter restriction, and tank air pressure are the primary hydraulic variables controlling RO production rate.

A technician is installing a point-of-entry iron reduction system using greensand media. What chemical must continuously be added upstream to ensure proper media function?

Answer: Potassium permanganate (KMnO₄)

Greensand media requires a continuous dose of potassium permanganate upstream to maintain its oxidizing capacity for iron and manganese removal.

Which installation error most commonly causes a salt bridge to form in a brine tank?

Answer: Placing the brine tank in a high-humidity location

High humidity causes surface moisture on salt pellets, which then recrystallize and fuse together forming a hardened crust (bridge) that prevents salt from reaching the water.

A customer reports occasional brown water only when hot water is run. The treatment system includes a water softener. What is the most likely cause?

Answer: Sediment from the water heater anode rod or tank corrosion

Brown discoloration only in hot water typically originates from the water heater's corroding sacrificial anode rod or scale buildup in the tank, not from the treatment system.

During a service call, a technician finds that a softener regenerates but immediately shows hardness breakthrough in the first liter of service water. What is the most probable cause?

Answer: The slow rinse (brine rinse) cycle is too short, leaving residual brine in the resin

An insufficient slow rinse leaves brine (high sodium and chloride) in the top portion of the resin bed, which flushes out first during service and can be detected as TDS or hardness carryover.

What is the primary reason a water treatment system installed on a well should include a check valve between the pump and the pressure tank?

Answer: To stop backflow of water into the well when the pump shuts off

A check valve prevents pressurized water from flowing back down into the well casing when the pump stops, protecting both the pump and maintaining system pressure.

A CWS technician is commissioning a new acid neutralizer (calcite filter) on a low-pH well water supply. What must be verified after the first week of operation?

Answer: That the outlet pH is between 7.0 and 8.0 and the calcite media level has not dropped excessively

Calcite dissolves to raise pH, so the outlet pH must be tested to confirm effective neutralization, and the media level must be checked since high-flow or very low pH water consumes calcite rapidly.