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(707) 539-4533 |  Sonoma Napa and Marin Counties

Too much air in your hot water heating system and network of pipes can cause a lot of problems for homeowners. The more noticeable problem is a hissing or gurgling noise; that, though, may be the least of your problems.

Why’s that? A hot water heating system that hasn’t been recently purged may cause a bottlenecking breakdown in the ability of the heating system to do its job. This could result in poorer circulation among the system’s warren of pipes and individual radiators.

Purging Air From a Hot Water Heating System 

Purging, or “bleeding,” air from a hot water system is essential for ensuring proper circulation and, in turn, a warm home. Most hot water systems are closed systems, which means that there’s always water circulating back and forth between the pipes and boiler.

Because of this closed system and the fact that most hot water heating systems don’t have an automatic purge system, you will need to purge or bleed your system every fall. Venting individual radiators and draining your boiler is essential for the proper functioning of your entire hot water heating system. Here’s how homeowners can get started:

  • Locate and begin with the radiator that’s the farthest from your hot water heating system’s boiler.
  • Locate the bleed valves in individual radiator units. The bleed valve is typically located at a top corner of the radiator unit itself.
  • Choose the right tool for the job. Radiator bleed valves can be opened one of two ways. The easiest valves are opened with screwdrivers with a straight-edge configuration. Some valves, contrastingly, require a square-figuration and the use of a radiator key.
  • After you’ve opened the valve, you’ll want to place some kind of holding receptacle (e.g., cup or bowl) under the spout. Trickles of water may come out of the spout even though your end goal is purging air from the system. This is perfectly normal and not something to panic over.
  • Keep turning your straight-edged screwdriver or radiator key in the valve until you only notice water seeping out of the valve.
  • Once you only have water running out of the valve, that’s an indication that the air has been purged from that individual radiator unit.
  • Now, that you’ve purged the air from one radiator unit, it’s time to move upstream and do the same thing for subsequent radiators closer to your hot water heating system’s boiler.
  • Once you’ve done all the individual radiator units, double back and check with the first radiator (then the second radiator, etc.) to ensure that only water is coming out of the valve.

If only water is coming out of your valve, then you’ve purged the air from your hot water heating system and should start enjoying heat this coming winter season – without any circulation problems or nasty gurgling noises in the pipes!

HVAC 101 Everything you need to know