Procedure For Flushing The Heat Exchanger - Noritz WHiC56 Service Manual

Procedure for Flushing the Heat Exchanger

Flushing the heat exchanger.
1
button is "ON".
2
Set the temperature more than 60 degrees.
3
Push button again, and water heater turns off.
4
Disconnect electrical power to the water heater.
5
Close the shutoff valves on both the hot
water and cold water lines (V3 and V4).
6
Connect pump outlet hose (H1) to the
cold water line at service valve (V2).
7
Connect drain hose (H3) to service valve (V1).
8
Pour chemical product used to flush heat exchanger
into water (acid 8-10% of water content).
9
Place the drain hose (H3) and the hose H2) to
the pump inlet into the cleaning solution.
10
Open both service valves (V1 and V2)
on the hot water and cold water lines.
11
Operate the pump and allow the vinegar
to circulate through the water heater for at
least 1 hour at a rate of 15 liters per minute.
12
Turn off the pump.
13
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).
14
Disconnect all hose.
15
Restore electrical power to the water heater.
Water
NOTE : Place a bucket under the water heater to
Drain Valve
drain water from the "Water Drain Valve".
Carefully unscrew the "Water Drain Valve"
to rinse flushing solution out of the water
heater for about 10 seconds, then close
the "Water Drain Valve".
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KEY
K EY
Pressure Regulator
3/4" Ball Valve
Circulating Pump
3/4" Union
Check Valve
Boiler Drain Valve
S
Pressure Relief Valve
Solenoid Valve
Water Heater
V1
H3
V3
Hot
Water
Line
H2
Circulating Pump
In-line
Filter
V2
V4
Gas
Cold Supply
Water
Line
H1