Noritz GQ-C2857WS US Owner's Manual page 19

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 equipment cools down before draining the water.
The appliance will remain hot after it is turned off.
High Temperature
To prevent damage from freezing, the water heater must be plugged into power at all times. If power is unplugged, drain the
water completely from the water heater. Then use an air compressor to remove all water from inside the unit's water piping.
It is recommended that Isolation Valves are installed on the water heater, otherwise the water connections will need to be
removed to drain the unit completely. Freeze damage due to not draining properly will not be covered under warranty.
Drain water into a bucket to prevent water damage.
1. Close the gas valve.
2. Turn off ther power button.
3. 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
Each drain plug mignt not be visible
if insulation is installed around the
piping.
Drain Plugs
19