Noritz NR501-OD Service Manual page 77

Preventing Damage from Freezing-2
If the water heater will not be used for a long period of time,
drain the water.
Drain the water as follows:
CAUTION
To avoid burns, wait until the unit cools down before draining the water.
The appliance will remain hot after it is turned off.
High Temperature
Drain water into a bucket to prevent water damage.
1. Close the gas valve.
2. <Not using the remote controller>
Fully open one of the hot water fixtures.
<Using the remote controller>
Turn off the power button.
3. <Not using the remote controller>
Turn off the power supply after 2 minutes or more pass from operation of 2.
Do not touch with wet hands.
<Using the remote controller>
Turn off the power supply.
Do not touch with wet hands.
4. Close the water supply valve.
5. Fully open all hot water fixtures.
6. Turn the drain plug to the left to open, and then remove.
7. Check that the water is completely drained, close all the
drain plugs and the hot water fixtures after 10 minutes
or more pass from operation of 6.
Fixture
Fixture
77
(Ex. NRC711-DV)
Drain Plugs
Each drain plug might not be
visible if insulation is installed
around the piping.