User Guide

40 RH180 Manual
Hybrid Tank-Tankless Flush Procedure
Use the following procedure to ush the heat exchanger of lime or scale build up. Damage caused by lime build-
up is not covered by the unit’s warranty. Aer ushing, reset any error codes by turning o the power to the
unit and turning the power back on.
H2
H3
H1
5 gallon pail of virgin,
food grade, white
vinegar (or virgin,
food grade, citric
DRAIN
PUMP
1
2
COLD
WATER-
SUPPLY
VALVE
HOT WA-
TER
VALVE
IN-LINE FIL-
TER
10.Turn o pump.
11.Rinse the cleaning soluon from the water
heater as follows:
a. Disconnect hose (H1) from the engine.
b. Connect a cold water supply ng and hose
to the IN-LINE FILTER ng at the base of
the engine (3/4” NPT).
c. Move drain hose (H3) from the pail to a
drain.
d. Open cold water supply and allow water to
ow through the engine for 5 minutes.
e. Remove, clean and replace the in-line lter.
f. Remove Hose (H3) and the cold water sup-
ply hose from the base of the engine.
g. Re-Install the (3/4” NPT) ex ngs and
to the assembly.
h. CLOSE THE DRAIN VALVE
i. Open the cold water supply valve unl wa-
ter ows from the hot water xture
j. Close the cold water supply valve.
k. Connect power to the water heater and
turn the temperature down to set point 1.
12.Open the cold water supply valve unl water
ows from the hot water xture (See Step
2).
13.Close the hot water xture and inspect
the appliance and plumbing for leaks.
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2
Do not connue unl all water has drained from the tank.
NOTICE
1.Disconnect electrical power to the water heater.
2.CLOSE the cold water supply valve. Leave the hot water valve and a hot water xture OPEN to remove pressure
from the system.
3.Connect one end of a hose to the drain valve on the tank and direct the other end to a drain. OPEN the drain valve.
4.Remove the (3/4” NPT) ex ngs and from the assembly. (Note: The tankless unit will sll contain
approximately 1/2 gallon of water. Prepare a bucket to catch this water.)
5.Connect pump outlet hose (H1) to the (3/4” NPT) in-line lter ng at the base of the engine.
6.Connect drain hose (H3) to the (3/4” NPT) supply ng at the base of the engine.
7.Pour approximately 4 gallons of virgin, food grade, white vinegar or citric acid into a pail.
8.Place the drain hose (H3) and the hose (H2) to the pump inlet into the cleaning soluon.
9.Operate the pump and allow the cleaning soluon to circulate through the water heater for at least 45 minutes.
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