Here are some product reviews. For a product to make it onto this list, it has to have some feature that distinguishes it from either a basic commodity, or must be a new product that allows the job to be completed faster, speeds up maintenance, or some other virtue.
Webstone Expansion Tank Service Valve
This valve connects into the bottom of the air separator, and creates a multi-prong joint where the expansion tank, water makeup feed, and drain valve can each be isolated or opened as needed for servicing.
Flexcon Hydronic Expansion Tank
This is a typical expansion tank used in most residential hydronic heating systems that have a closed loop.
Caleffi Dirt Separator
This product uses a low-velocity zone and a high-temperature plastic screen to allow particles to drop out of the water stream and down into the dirt separator's reservoir. As part of the system's regular maintenance, the bottom valve is opened and the dirt blown down and out of the system.
Pro:
not having to buy replacement filters
Con:
In an existing dirty system, if you do not blow down the dirt often enough, the system pressure may not be sufficient to unblock the valve because of accumulated sludge. In this case, the contractor must push something into the reservoir through the valve in the bottom to unblock it. Generally requires weekly visits until the system debris is back to maintenance levels.