Flushing the Heat Exchanger (Error Code: LC or 00)
An “LC” or “00” error code indicates the unit is beginning to lime up and must be flushed. Failure to flush the appliance will cause damage to the heat exchanger. Damage caused by lime
1. | Disconnect electrical power to the water heater. |
2. | Close the shutoff valves on both the hot water and cold |
| water lines (V3 and V4). |
3. | Connect pump outlet hose (H1) to the cold water line at |
| service valve V2. |
4. | Connect drain hose (H3) to service valve V1. |
5. | Pour approximately 4 gallons of virgin, food grade, white |
| vinegar or citric acid into pail. |
6. | Place the drain hose (H3) and the hose (H2) to the pump |
| inlet into the cleaning solution. |
7. | Open both service valves (V1 and V2) on the hot water and |
| cold water lines. |
8. | Operate the pump and allow the cleaning solution to |
| circulate through the water heater for at least 45 minutes. |
9. | Turn off the pump. |
10. | Rinse the cleaning solution from the water heater as follows: |
| a. Remove the free end of the drain hose (H3) from the pail. |
Water Heater
| b. Close service valve, (V2), and open shutoff valve, (V4). |
| Do not open shutoff valve, (V3). |
| c. Allow water to flow through the water heater for 5 minutes |
| d. Close service valve, (V1), and open shutoff valve, (V3). |
11. | Disconnect all hoses. |
12. | Remove the |
| any residue. Place filter back into unit. |
Filter
V1 V2
Gas Supply
13. Restore electrical power to the water heater. | H3 |
|
V3 
V4
5 gallon pail of virgin, food grade, white vinegar (or virgin,
food grade, citric acid).
| KEY |
3/4" Ball Valve | Pressure Regulator |
| |
3/4" Union | Circulating Pump |
Check Valve | Boiler Drain Valve |
Pressure Relief Valve | S Solenoid Valve |
Cold Water Line Hot Water Line
H2
H1
Circulating Pump
12 | 305, 505, 705 Indoor Manual |