We have a Spirovent Air-Separator on the hydronic heating system, between the boiler and the circulator. How to determine if it is working properly to remove dissolved air bubbles and has not been clogged by minerals in the water?

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2 Answers 2


The maintenance and operation documentation, for what I think is your model, provides the following steps if service is required.

WARNING! System fluid under pressure can be very hazardous. Before removing the vent head for inspection, reduce system pressure to zero, or isolate the Spirovent from the system. Allow the system to cool to below 100°F. Failure to follow these instructions may cause serious bodily injury or property damage.

  1. Using two strap wrenches, hold the body in place in the piping while removing the vent head, taking care not to damage the O-ring. Pipe wrenches may be used, but they can leave marks in the brass.
  2. To clean the vent head, use a mild detergent and water or vinegar and water solution. For extremely dirty conditions, soak the head in mineral spirits for several hours and then clean thoroughly. The vent head is available as a replacement part if necessary. Use part number PJR000HA. Assembly includes the O-ring.
  3. While the vent head is removed, remove the coalescing medium from the body and rinse thoroughly with mild detergent and water or vinegar and water to remove any system contaminants.
  4. Examine O-ring before installing on the Spirovent and replace if necessary. Use part number PJR000RG.
  5. Reassemble the Spirovent.
  6. Return system to operating condition.

It's a bit of work, but I think it will be the most complete way to ensure the vent is in good condition.


My spirovent stopped working so I tried back pressure. Held a bicycle pump against the vent until it sealed and then tried to compress the pump. Initially nothing, just pressure build up, then suddenly it compressed and I could hear air going into the system. Works just fine again. Valve must just have been stuck.

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