Flushing The Heat Exchanger - Rinnai RSC199i Installation And Operation Manual

6.3 Flushing the Heat
Exchanger
This water heater includes a service indicated/
reminder (Service Soon, SS). When selected in
the parameter settings, an SS code will display
on the controller indicating that it is time to flush
and service the water heater. Failure to flush
the appliance will cause damage to the heat
exchanger. Damage caused by lime build-up
is not covered by the water heater's warranty.
Rinnai strongly recommends installation of
isolation valves to allow for flushing of the heat
exchanger.
1. Turn off power at the controller.
2. Disconnect electrical power to the water
heater.
3. Close the shutoff valves on both the hot
water and cold water lines (V3 and V4).
4. Connect pump outlet hose (H1) to the cold
water line at service valve (V2).
5. Connect drain hose (H3) to the hot water
line at service valve (V1).
6. Pour four gallons of undiluted virgin, food
grade, white vinegar into pail.
7. Place the drain hose (H3) and the hose (H2)
to the pump inlet into the cleaning solution.
8. Open both service valves (V1 and V2) on
the hot water and cold water lines.
9. Operate the pump and allow the vinegar to
circulate through the water heater for at least
1 hour at a rate of four gallons per minute
(15.1 liters per minute).
10. Turn off the pump.
11. 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 out-
side to drain.
B. Close service valve (V2) and open shutoff
valve (V4). Do not open shutoff valve
(V3).
Rinnai Tankless Water Heater Installation and Operation Manual
C. Allow water to flow through the water
heater for five minutes.
D. Close shutoff valve (V4). When unit has
finished draining remove the in-line 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).
12. Disconnect all hose.
13. Restore electrical power to the water heater.
NOTE
Scale build-up will affect the performance of the
water heater. Water should be treated. Rinnai
offers Southeastern Filtration's "ScaleCutter
Water Conditioning System" that offers superior
lime scale prevention and corrosion control by
feeding a blend of control compounds into the
cold water supply.
Figure 94
85