Barksdale Pressure Switch Manual

Working with Barksdale Pressure Switches

Most people pick up a Barksdale pressure switch because something downstream failed and they need to replace the component that was supposed to catch it. That is the normal order of events. The manual helps, but not always where you would expect it to help most.

Downloading the Barksdale Pressure Switch Manual

The most reliable source is the Barksdale website itself. Go to their support section, search by part number, and download the latest revision. Sometimes the manual you find online is a few revisions behind what shipped with your unit, especially if you picked up a refurbished switch from a distributor. Always check the date on the document. If it predates 2018, it is probably missing updates on the newer Series 2000 and 2010 models that changed the setpoint adjustment mechanism.

Reading the manual correctly

The first thing most people miss is that Barksdale manuals do not give you a single universal procedure. The wiring diagram for a Series 62 pressure switch looks completely different from the 2000 series, and the setpoint adjustment section changes between models too. I learned this the hard way. A few years ago I was on a job replacing a pressure switch on an industrial compressor. I followed the wiring procedure from what I thought was the right manual, powered up the panel, and watched the control board throw a fault within ten seconds. The switch was wired correctly for its own model, but I had been looking at a manual for a different actuator type from the same product family. It took me about forty minutes to realize my mistake. The workaround was simple but annoying: pull the nameplate off the switch, read the full part number including the suffix, and search again using that exact string. Suffixes like 0-150 PSI, R1, or 0-10 BAR are not cosmetic. They change the internal contact arrangement.

The manual does cover this, but it buries it. The part number decode table is usually on page two or three, and it is easy to skim past when you are in a hurry. Do not skim it.

Setpoint adjustment reality

The adjustment procedure in the manual assumes you have a deadhead test setup, which most people do not keep on hand. What actually works in the field is simpler. Connect the switch in line with your process, pressurize slowly, and watch the pressure gauge while listening for the click. Mark the trip point on a piece of tape and stick it to the gauge housing so you can compare closing pressure on the next cycle. This takes about fifteen minutes for a full open-close-open cycle and gives you real-world data instead of theoretical numbers.

The manual lists tolerance as plus or minus a percentage of span, but that tolerance applies to factory conditions with clean dry air at a stable temperature. If your process media is oily or wet, or if the switch cycles frequently, the actual repeatability degrades. I have seen switches drift by nearly double the published tolerance after six months of heavy cycling in a humid environment. There is no workaround for that except more frequent recalibration or selecting a switch with a higher duty rating.

Wiring pitfalls

One counter-intuitive thing about Barksdale switches is how the contacts are rated. The manual shows the contact ratings clearly, but the ratings drop significantly when you are switching inductive loads versus resistive loads. A switch rated for 10 amperes on a resistive load might only handle 3 amperes on an inductive load like a contactor coil. Beginners often wire a pilot circuit directly through the switch contacts without checking the load type, and the contacts weld shut within weeks. The manual mentions this in a small table near the end. Read that table before you terminate the wires.

Another thing the manual does not stress enough is the importance of the thread sealant. Barksdale switches use NPT threads, and over-tightening with pipe dope on the process threads can crack the sensing element housing. I have cracked two of these while trying to make a leaky connection seal. The fix is to use thread seal tape instead of dope, apply it carefully, and torque to about two finger-tight turns past hand-tight. That is the range where the seal holds without risking the housing.

When the manual is not enough

The manual assumes a standard installation. It does not cover vibration isolation, which matters if the switch is mounted on a reciprocating pump or a high-vibration compressor. Vibration causes false triggering that looks like a faulty switch but is actually just the mechanism rattling open and closed. I dealt with this on a mobile hydraulic unit where the manual suggested a simple direct mount. The switch kept tripping erratically. The solution was adding a remote capillary sensing line instead, which the manual does mention but treats as an afterthought. The remote line option is listed in the accessories section with part numbers, and it is the correct fix for any application with vibration above 0.5 G RMS at the mounting point.

There is also a limit to how low you can go with differential adjustment on certain models. The manual shows the adjustment range on the specification chart, but the usable range is often narrower than the published span suggests. On the Series 2000, the minimum adjustable differential is about 10 percent of the full scale range. Trying to set a differential smaller than that will not work, and the manual does not warn you explicitly about this. You find out when you turn the adjustment screw and the setpoint barely moves.

Quick reference for common models

Series 2000 and 2010 use the same basic adjustment method but the 2010 has a digital readout option that the 2000 lacks. The manual for the 2010 is longer because of the programming section. Series 62 is an older design with a different contact block that is still common in replacement work. The XAL and XBP lines are mostly for refrigeration and HVAC applications, and their manuals reference oil resistance ratings that do not apply to the general industrial switches. Mixing those up causes problems because the seal materials are different.

If your manual is missing a section or the revision number does not match your part, Barksdale customer support will send the correct document within a business day. Their part number lookup is more reliable than searching by model name alone. Type the full catalog number from the nameplate and you will get the exact revision. This saves time compared to guessing from pictures on forum threads, which are often wrong about the wiring configuration.