How do you bleed a hot water heating system?

Answer

to get your hot water system ready for winter, at the boiler,i blow out any dust and dirt from the bottom of the unit which has a door with 2 knobs on it. could be different on others. pull gently to remove it. you can see dirt that has fallen down on bottom. i vacuum up what i can with my shop vac, then i empty the shop vac and reverse the hoses to blow out any dust or dirt left behind. then i replace the door back on correctly and then turn up the thermostat to high for a good 1/2 hour to an hour to get water up to temperature.

somewhere on your hot water system, there should be a valve to loosen to allow air and water to escape when loosened.( not removed ) just loosened. when you loosen the valve you have to hold a container under to catch hot water that will come out. if air is in the tank you will here it hissing, and water and air will come out together. air is cleared when just water comes out without any noises or sputtering.

gently tighten valve back snug tightly. do not over tighten or you could break the fitting. just snug tight. follow this procedure on all your heating tanks starting at the farthest one away from your boiler working your way to the closest one to the boiler. that should take care of any air in your system.

turn your heat back down to proper temperature.

First answer by 4work. Last edit by 4work. Contributor trust: 80 [recommend contributor]. Question popularity: 101 [recommend question]