Non-Condensing Models - AO Smith Water Heaters

Troubleshooting GuideDESCALING THE UNITHard water is a severe problem for the copper coils inside heat exchangers. Heat exchangerfailure due to scale buildup from hard water conditions is NOT covered by warranty. It is highlysuggested that a scale inhibitor be installed before the cold water inlet after this procedure isdone.1) TOOLS ‐ Gather the following materials together:a. Pump: The pump should provide a minimum of1GPM through the heaterb. Cleaning Solution: Food grade citric acid, foodgrade phosphorus acid.c. Water hosesd. Bucket2) SETUP ‐ Disconnect power to the unit3) WATERLINES – Assumes isolation valves with drainports are installeda. Isolate the unit by closing the incoming/outgoingwater isolation valves C and D.b. Connect hoses/pump to the drain ports of theisolation valves: Outlet of the pump to valve B,and another hose from Valve A to the bucket.4) PUMP –a. Fill the bucket with 5 gallons of diluted solution.Dilution ratio depends on the cleaning solutionused.b. Place the pump into the bucket if it is submersible,or use an inlet hose into the bucket if it is notsubmersible.Figure 355) DESCALEa. Open valves A and B.b. Circulate descaling solution through the unit for 45 minutes.6) CLEANSE THE SYSTEM – Flush the chemicals out of the heat exchanger with fresh water.a. Close valve A and B.b. Open valve D and run fresh water through the PRV for 15 minutes.c. Clean the filter after flushing the unit with fresh water.d. Once the unit is flushed and cleansed, close A and B, open C and D, and reconnect power to theunit.321923‐00032| Page