4-3
MAINTENANCE
TANKLESS WATER HEATER 199
The recommended pH of the domestic water is between 6.5 and 8.5. The internal
domestic water heat exchanger tubing and the flow sensor are subject to fouling
if exposed to hard water (over 7 grains of hardness) or has a TDS of 500mg/L or
higher.
See Table 12.
DESCRIPTION
MAX
MIN
Water Pressure
150 psi
40 psi
Programmable water temperature
149°F (65°C)
104°F (40°C)
Minimum Flow Rate to Activate DHW Sensor
N/A
0.5 GPM
Acceptable pH range
8.5 pH
6.5 pH
Total Dissolved Solids
500 mg/L
Total Hardness
200 mg/L 11.68 gr/gal
Aluminum
0.05 to 0.2 mg/L
Chlorides
250 mg/L
Copper
1.0 mg/L
Iron
0.3 mg/L
Manganese
0.05 mg/L
Zinc
5 mg/L
Table 12: Domestic Water Quality Guidelines
4.1.12 DHW Filter cleaning instructions
Clean the DHW water filter during annual maintenance as follows:
1.
Turn off the unit and disconnect power.
2.
Turn off the DHW hot and cold isolation valves.
3.
Place a bucket under the drain and drain the DHW water from the unit.
4.
Unscrew the water filter from the unit’s cold water inlet.
5.
Clean the water filter under running water. Use a soft brush if necessary.
6.
Reinstall the water filter in the unit’s cold water inlet.
7.
Open the DHW hot and cold isolation valves.
8.
Reconnect the power and return the unit to operation.
4.1.13 Fan removal instructions
1.
Turn off the power and the gas supply to the unit.
2.
Remove the front cover, and allow the unit to cool down.
3.
Disconnect the electrical plug attached to the fan.
4.
Loosen the union nut at the top of the gas valve. Carefully remove the orifice
and O-ring, and keep in a safe place for re-installation later. Ensure you
protect the gas valve outlet from dust and debris.
5.
Remove the 2 hex nuts connecting the fan to the burner housing, and
carefully remove the fan. You will find a gasket attached to the fan outlet as
well as an internal check valve. Keep these items in a safe place for re-
installation.
6.
If the removed fan is to be re-installed, ensure the fan and venturi are clean
and dust free. If the fan is being replaced, move the venturi over to the new
fan. Note that the fit is tight.
CAUTION
Before testing the relief valve,
make certain the discharge
pipe is properly connected to
the valve outlet, and arranged
to contain and safely dispose
of equipment discharge.