To clean the water side of the boiler after installation one pound of trisodium phosphate for each ___ gallons of water

• A. 50
• B. 25
• C. 75
• D. 100

Answer: (A)

Cleaning the water side effectively relies on using a cleaning bath with trisodium phosphate in a precise amount based on how much water you’re treating. The standard practice is to add one pound of trisodium phosphate for each 50 gallons of water. This gives enough alkalinity to break down oils, flux residues, and other deposits without making the water overly caustic, which could cause foaming, high pH problems, or damage to gaskets and metal surfaces.

Because the dosage scales with volume, the amount you add should increase proportionally as the tank or boiler holds more water. For example, if you had 100 gallons, you’d use about 2 pounds; for 25 gallons, about half a pound. Sticking to this ratio helps ensure the cleaning effect is achieved consistently across different sizes of equipment.

Other numbers would misalign with the established cleaning guideline: too little may not remove residues effectively, while too much could create excessive alkalinity and related issues.