Navien CH-180, Service Manual, Page: 118 / 155

© Navien Ameri c a I n c . 20 1 0 CH series servi c e Manua l
116
Version 1 .0
7. Maintenance
7.1. Draining the Combination Water Heater / Boiler
Describe precautions before maintenance, and show tools required when maintenance.
Procedure to drain the unit (figure below). You will need to prepare a bucket to
collect some of the water to be drained.
1. Turn off the power to the unit.
2. Close the gas valve
3. Close the water supply valve on the space heating return to the unit. If there is
no valve, turn off the water supply valve at the water meter.
4. Open the pump drain plug on the pump and allow the water to drain.
5. Open the pump drain plug at hot outlet side, open the drain valve inside the unit,
open the drain valve at the pump and remove the filter from the space heating
return side.
6. When the water is completely drained, return the pump drain plug and the inlet
filter and close the pump drain plug inside the unit.