Rinnai Infinity 20 External Operation And Installation Manual page 38

Flushing the heat exchanger procedure:
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 chemical product used to flush heat exchanger
into water (acid 8-10% of water content).
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 circulation through the
water heater for at least 1 hour at a rate of 15 liters
per minute.
9. Turn off the pump.
10. Rinse the chemical/water from the water heater as
follows:

a. Remove the free end of the drain hose (H3) from
the pail. Place in sink or outside to drain.

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 shutoff valve (V4). When unit has finished
draining remove the inline filter at the cold water
inlet and clean out any residue. Place filter back
into unit and open valve (V4).

e Close service valve, (V1), and open shutoff valve,
(V3).
11. Disconnect all hose.
12. Restore electrical power to the water heater.
38
KEY
Pressure Regulator
3/4" Ball Valve
Circulating Pump
3/4" Union
Check Valve
Drain Valve
S
Pressure Relief Valve
Solenoid Valve
water heater
V1
H3
V3
H2
Circulating pump
Rinnai
V2
V4
H1