Practice Tips #99: The Evolution of the Master Valve

We’ve discussed master valves and their function in several previous issues of Practice Tips. Master valves provide on/off control for air or water to your delivery system. Most masters also incorporate some sort of filter assembly. Maintaining these filters is vital to keeping these valves working well and keeping your air and water flowing.

At their hearts, all master valves are fundamentally the same; they provide a means of turning the air or water on and off using air pressure to do so. They are used with a regulator that controls the air or water pressure. Sometimes the regulator is remote and attached to the master via a hose, sometimes the regulator is attached directly to the master (as shown below).

old-style master valve

Old-style master on/off valve with regulator screwed into it.

Sometimes, the master incorporates a regulator within the design. Our master/regulator combination valve is an example of a master and regulator together in a single valve.

#05-54 Master Regulator Combo Valve for Air

This valve features a master on/off control and a regulator all in one valve. It was designed specifically to replace a master valve with a separate regulator attached to it (the two valves were typically screwed together as shown above).

Let’s look at the versatile #05-54 valve a little more closely.

First, there is a filter assembly. Unlike previous incarnations of valve, the filter is placed directly after the inlet connection to your source air or water, so all air or water is filtered before it goes into the valve. This placement of the filter helps keep debris out of your lines and keeps everything flowing properly.

Master On/Off Filter Assembly and Air/Water Inlet

Be sure to check the filter regularly, so it stays clear. We recommend quarterly inspection at a minimum, but your needs may vary. For example, if you have hard water, you may want to check your water filter every month.

Access the filter by unscrewing the air/water inlet

Next, we have the actual master valve. An air signal is delivered to this valve to activate the air or water (whichever the valve is being used for), allowing it to flow through to the rest of the valve. Problems in this portion of the valve will generally prevent or severely restrict air or water flow.

Master on/off section of a combo valve

A unique feature of this valve is the large nut on the bottom of the master portion of the valve. Removing this nut will expose the interior of the valve, making it easy to push out the valve stem for cleaning and servicing.

Location of nut to access master on/off valve stem

Last of all, we have the regulator. It is in this portion of the valve that the air or water pressure is set. The large gauge on top of the valve will indicate the set valve pressure. NOTE: because the gauge is mounted at the regulator portion of the valve, it’s normal for the gauge to read zero (“0”) if the air or water is turned off (as the master portion comes before the regulator). The gauge will read the active pressure once the valve is turned “on.” There is a small set screw on the front of the valve that allows you to adjust the pressure, although the valves are factory preset, so you shouldn’t normally need to adjust them.

Regulator portion of combo valve

Normal pressure settings for your valves are 80 psi for air and 40 psi for water. For more on the importance of these settings and how to adjust them, see some of our previous issues of Practice Tips (#3, #23, #69, & #73). All of the connections on the regulator portion of the valve are regulated outlets. These ports provide regulated air or water to your delivery unit. There are 6 ports available for connections. We provide you with various size barbs & plugs, so you can use all of the ports or only one of them and connect either ¼” o.d. or 1/8” o.d. tubing to any individual port (as you require).

Outlets on air master on/off combo valve

Air master on/off valve regulated air outlets

As you can see, the #05-54 master regulator combo valve serves a vital function and works very well to replace other bulkier valves or combinations of multiple valves.