Use and Care Manual
67
Figure 44 – Valve and Hose Connection Details
Check the Burner
Clean the exterior of the burner.
Flushing the CH Closed 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 ush 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 ush 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 CH supply and CH
return lines (V1 and V2). See Figure 44.
3. Connect one hose (D1, Figure 44) 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 ow through the appliance for 5 minutes.
e. Close shutoff valve V2.
8. Disconnect hoses from lines. Properly dispose of used cleaning solution.
9. Remove the CH lter from the appliance and clean out any residues.
10. Repeat process on the DHW loop of the appliance.
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Read the temperature and pressure gauge to ensure the system is pressurized. Minimum is 10 psi. Maximum is 25 psi. Lift the relief valve top
lever slightly, allowing water to relieve through the valve and discharge piping.
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If water ows freely, release the lever and allow the valve to seat. Watch the end of the relief valve discharge pipe to ensure that the valve does
not weep after the line has had time to drain. If the valve weeps, lift the lever again to attempt to clean the valve seat. If the valve does not
properly seat and continues to weep, contact a qualied service technician to inspect the valve and system.
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If water does not flow from the valve when you completely lift the lever, the valve or discharge line may be blocked. Immediately shut the
appliance down per instructions on page 2 and call a qualied service technician to inspect the valve and system.
V1
V2
V4
V3
D1
D2
D3