Noritz NC250-SV-ASME Guide De L'utilisateur page 23

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The water is cold when only a
single fixture is open.
Fluctuations in hot water
temperatures.
Setting temperature cannot rise.
The amount of hot water at a
certain fixture is not constant.
The amount of hot water in the tub
is less/more than the set amount.
The flow meter alarm does not
sound even when filled to the set
amount.
Amount of hot water available
has decreased over time.
• The unit will not heat the water if the flow rate is less than
2L/min. (0.5 GPM).
Open the fixture more or open other fixtures so that a greater
flow passes through the unit, and the unit should begin
heating again.
• Set water temperature at 48°C (118°F) to 50°C (122°F).
This will allow you to use a higher flow of hot water thus
meeting the minimum flow requirement of 2L/min.(0.5 GPM).
• Clean the water filter of any debris (
• Is the maximum temperature setting appropriate? (
Amount of Hot Water
• When hot water is demanded at other fixtures, the amount
available may be reduced. The maximum flow available
from this unit is 35.2L/min. (9.3 GPM) at a 25°C (45°F)
temperature rise.
• Pressure fluctuations and other plumbing conditions can
cause the temperature and pressure at a fixture to be
unstable, but it should stabilize after a short time.
• There are some types of hot water taps that discharges large
volumes of hot water at first but stabilize after time.
• To keep the temperature stable, the heater limits the
amount of water that can flow through it to a small amount
initially, but the amount increases over time.
• When hot water is used for other fixtures while filling the
bath tub, the tub will not fill as much.
• If there is water in the tub already, or when filling is stopped
and restarted, the tub will fill more.
• The flow meter alarm is set to sound when hot water
is continuously discharged for the set volume of water.
If mixing valves are used, or if cold water is mixed with hot
water at the fixture, the tub will fill more than the setting
of the flow meter alarm.
• Is the water filter clogged? (
• If the supply water is hard and has not been treated, scale
can build-up in the water heater and decrease the
maximum amount of hot water available. Scale can be
removed from the water heater by flushing the unit
periodically. To prevent scale from forming in the water
heater, a water softener or scale inhibitor is recommended.
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