If a steam boiler runs out of water, severe damage may be done to the system. Because automatic water feeders add makeup water to the system as required, they act as a kind of safety device, avoiding the risk associated with manual water feeders.
If you have a manual water feeder, check the water level at least once a week to determine the boiler's water usage rate. It is unnecessary to obtain this information for automatic water feeders.
Add water through the manual water feeder valve when the level in the boiler's sight glass has dropped below the indicator line. Use the indicators on the sight glass to ensure enough water has been added.