38 Value Series Manual
Water Heater
Pressure Relief Valve
3/4" Ball Valve
3/4" Union
Check Valve
S
Pressure Regulator
Circulating Pump
Solenoid Valve
Boiler Drain Valve
KEY
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V1
V3
V2
V4
H1
H2
H3
Circulating Pump
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Rinnai
An LC0~LC9 or “00” diagnosc code indicates the unit is beginning to lime up and must be ushed. Failure to
ush the appliance will cause damage to the heat exchanger. Damage caused by lime build-up is not covered by
the unit’s warranty. Rinnai strongly recommends installaon of isolaon valves to allow for ushing of the heat
exchanger.
1. Disconnect electrical power to the water heater.
2. Close the shuto 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 4 gallons (15.1 liters) of undiluted virgin, food
grade, white vinegar into pail.
6. Place the drain hose (H3) and the hose (H2) to the
pump inlet into the cleaning soluon.
7. Open both service valves (V1 and V2) on the hot
water and cold water lines.
8. Operate the pump and allow the vinegar to circulate
through the water heater for at least 1 hour at a rate
of 4 gallons per minute (15.1 liters per minute).
9. Turn o the pump.
10. Rinse the vinegar 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 shuto valve,
(V4). Do not open shuto valve, (V3).
c. Allow water to ow through the water heater for
5 minutes.
d. Close shuto valve (V4). When unit has nished
draining remove the in-line lter at the cold water
inlet and clean out any residue. Place lter back
into unit and open valve (V4).
e. Close service valve, (V1), and open shuto valve,
(V3).
Flushing the heat exchanger
11. Disconnect all hoses.
12. Restore electrical power to the
water heater.
Following ush procedure call
technical assistance (1-800-621-
9419) for PCB reset informaon.