Westinghouse WBRC 140W Series Installation Manual page 75

10. Repeat process on the DHW loop of the appliance.
Flushing the DHW Loop Heat Exchanger
Flushing the heat exchanger is a complicated procedure that should only be performed by a qualified service technician. It is
recommended to flush the heat exchanger annually if water hardness exceeds 12 grains per gallon (considered extremely hard water).
If water hardness falls below 12 grains per gallon it is recommended to flush the heat exchanger every two to three years.
NOTE: Improper maintenance WILL VOID appliance warranty.
1. Disconnect electrical power to the appliance.
2. Close the shutoff valves on both hot water outlet and cold water inlet lines (V1 and V2). See Figure 58-A.
3. Connect one hose (D1, Figure 58-B) to the valve (V3) and place the free end in a bucket. Connect one of the hoses (D3) to the
circulation pump outlet and the cold water inlet line to valve V4. Connect the other hose (D2) to the circulation pump inlet and place the
free end in the bucket.
4. Pour tankless cleaning solution into the bucket. Use an FDA approved cleaner for potable systems on the heat exchanger. Place the
drain hose (D1) and hose D2 to the pump inlet in the cleaning solution.
5. Open service valves (V3 and V4) on the hot water outlet and cold water inlet lines.
6. Turn on the circulation pump. Operate the pump and allow the cleaning solution to circulate through the appliance for at least 1 hour
at a rate of 4 gallons per minute.
7. Rinse the cleaning solution from the heat exchanger as follows:
a. Remove the free end of drain hose D1 from the bucket.
b. Close service valve V4 and open shutoff valve V2.
c. Do not open shutoff valve V1.
d. Allow water to flow through the appliance for 5 minutes.
e. Close shutoff valve V2.
8. Disconnect hoses from lines. Properly dispose of used cleaning solution.
Figure 58 – A – Valve, and B – Hose Connection Details
10. Remove the DHW inlet filter from the appliance and clean out any residues.
Cleaning the CH and DHW Inlet Filters (Draining the Appliance)
1. Place a bucket under the appliance to collect the residual water inside the appliance.
2. Press the Power button on the control panel to turn off the electrical power to the appliance. Then turn off the gas valve.
3. Valve off the appliance from the system. If the appliance cannot be isolated from the system, turn off the main water valve.
4. Open the hot water faucets in the system to aid in draining the system.
Water drained from the appliance could be scalding hot. Wait for the appliance to cool before removing the CH or DHW inlet filters.
Failure to do so could result in property damage, personal injury, or death.
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WHL-012 REV. 4.8.16