A pressure regulator is a single component that handles only pressure: it reduces incoming pressure to a set value and holds it there. An FRL unit (filter–regulator–lubricator) combines a filter, regulator and lubricator in order — filter first, then regulate, then lubricate. It is not simply one or the other: an FRL unit already contains a regulator, and sources say a combination need not have all three stages — some equipment needs no lubrication and uses only a filter and regulator. The difference is “pressure only, or treating the air supply as a set,” and there are four places to look: function, components and order, lubrication, and regulation and selection. Here, regulators and FRL units mean compressed-air treatment components for pneumatic systems; hydraulic valves, vacuum regulators, electronic proportional regulators and air dryers are outside the scope. It is organized in four comparisons:
- ① Function: one manages pressure; the other treats the air supply as a set.
- ② Components and order: a single component versus three stages of filter, regulator and lubricator.
- ③ Lubrication: whether to add it — sources say not every set needs it.
- ④ Regulation and selection: regulator type and range, versus matching the whole set.
This article starts from the point where you already know pneumatic equipment needs stable compressed air; sources are summarized at the end. It is a selection summary, not piping design, and does not replace component makers’ specifications or equipment manuals; pressure, flow and lubrication conditions depend on your site and maker data. For regulator selection, see “How to choose a pressure regulator”; the site has no “how to choose” page for FRL units yet, so this article covers the difference between them. This describes the general case; individual cases still need their own assessment.
Figure 1. Four comparisons (illustration, not to scale): ① function — regulator: pressure only, reduced to a set value and held; FRL: three stages in one set. ② components and order — regulator: one component, regulation only; FRL: filter, regulator, then lubricator. ③ lubrication — regulator: none, add separately if needed; FRL: includes a lubricator, which can be omitted if the equipment doesn’t need it. ④ regulation and selection — regulator: relieving or non-relieving, range close to working pressure; FRL: port sizes across stages and whether the equipment needs oil.
Comparison ①: Function — one manages pressure, the other treats the air supply as a set
- First write down: whether the problem is unstable or excessive pressure, or water and contaminants in the air, or equipment needing oil.
- If you only need to reduce pressure to a set value and hold it, look at a regulator.
- If you need to handle contaminants and water, pressure and oil together, look at an FRL unit.
- They are not substitutes: an FRL unit contains a regulator.
What public sources say: a tutorial on a pneumatics retailer’s site (25 March 2021; signed, no affiliation stated; tutorial with product links and sign-up prompts — Source 1) says the filter is the first stage, cleaning air from the compressor and separating liquid contaminants such as water or oil; the air is then regulated to a fixed output pressure; and the lubricator adds a controlled amount of lubricating oil after cleaning and regulation. An industrial supplier’s web page (published 18 September 2024, metadata shows revised 12 August 2025; signed; supplier’s claims, with promotion — Source 2) says the filter removes moisture and contaminants, the regulator keeps pressure stable so downstream components are not overloaded, the lubricator adds controlled oil mist for components needing lubrication, and the unit puts all three functions in one assembly.
Comparison ②: Components and order — a single component versus three stages
- First write down: which stages are installed now and where.
- A regulator is one component with only the regulating stage.
- An FRL unit, in the sources’ order, is filter, regulator, lubricator; the lubricator sits close to the equipment using the air.
- A combination need not have all three stages; it can be filter and regulator only.
What public sources say: Source 2 says the common installation order is compressor, filter, regulator, lubricator, with the lubricator usually last, close to the components using it; a filter–regulator-only combination is used for self-lubricating equipment that needs only clean, controlled air. A pneumatic parts company’s catalog page (published 17 November 2014, updated 27 April 2026; signed; maker’s claims, with shop links and an inquiry button — Source 3) gives the order filter, regulator, then lubricator; the filter removes solid particles and liquid water but not water vapor, which needs a refrigerated or desiccant dryer; a shut-off valve usually goes before the unit and a soft-start valve after it. An automotive repair trade magazine article (18 November 2021; signed; written by a pneumatic equipment supplier, ending with promotion of its own guides and videos — Source 4) says the lubricator follows the filter as the last stage, near the point of use, and filter, regulator and lubricator are often combined in one unit near the tool. Source 1 says makers now mostly supply the three combined in one.
Comparison ③: Lubrication — whether to add it; sources say not every set needs it
- First write down: whether the equipment manual requires lubrication, and which oil.
- Sources say that if connected equipment needs no added oil, the lubricator can be omitted.
- Only for equipment needing lubrication choose an FRL unit with a lubricator.
- Sources say a lubricator running dry or delivering too much oil can both cause problems.
What public sources say: Source 1 says self-lubricating pneumatic tools need no separate lubricator. Source 2 says many modern pneumatic tools are self-lubricating and may not need a separate lubricator, using a filter plus regulator instead. Source 3 says the lubricator adds oil mist for actuators that need it, and is also recommended in humid, dusty environments, for actuators moving above 1 meter per second, and for valves switching above 3 hertz (more than 3 times per second); most pneumatic actuators run without added lubrication. Source 4 says commonly used air tools such as impact and ratchet wrenches usually need a lubricator, while tire inflators and spray equipment need little or none, and an unnecessary lubricator may reduce tool performance. An article in an industrial automation publication (28 May 2017, revised 23 April 2025; signed by a pneumatic product manager at a supplier, first published on the company blog — Source 5) says lubricators are now rarely used on new pneumatic machines, modern seals often need no added lubrication, some air tools, air motors and air clutches still need internal oil, and a lubricator running dry can make components stick or slow, while too much oil is exhausted as oil puddles or mist.
Comparison ④: Regulation and selection — regulator type and range versus matching the set
- First write down: the set pressure range, air consumption, and whether excess air should be vented when downstream pressure drops.
- For a regulator, look at the type — relieving (venting) or non-relieving — and choose a range close to the pressure you will use.
- For an FRL unit, look at the whole set: port sizes must match across stages, and check whether the equipment needs oil.
- The sources give no dividing line for “move from a single regulator to an FRL unit”; it depends on equipment and air supply.
What public sources say: a regulator maker’s web page (last modified 11 July 2024; unsigned; maker’s claims, with promotion — Source 6) says a regulator reduces inlet pressure to a set outlet pressure; a relieving regulator vents excess downstream pressure to atmosphere, so outlet pressure drops at once even with no flow, which is often more convenient in pneumatic systems; a non-relieving regulator does not vent, so downstream pressure does not drop immediately without flow, only falling to set point when air is used. Source 1 says relieving regulators lower pressure and automatically vent excess downstream pressure, while non-relieving ones need a separate exhaust valve. Source 3 says the regulator holds outlet pressure at the level the application needs, most regulators should be adjusted upward from low, and working pressure should fall within the range, as near the top as possible. Source 2 says every pneumatic system still needs at least a filter and a regulator; the three components can also be used individually; self-lubricating equipment uses a filter plus regulator; and the right choice depends on pressure, flow, air quality needs and whether the equipment needs oil.
Comparison table: the four points at a glance
| Item | Pressure regulator | FRL unit |
|---|---|---|
| Function | Reduces pressure to a set value and holds it | Filter, regulator and lubricator in one set |
| Components and order | Single component, regulation only | Filter, regulator, lubricator in order; can be filter and regulator only |
| Lubrication | No lubricator | Includes a lubricator; sources say it can be omitted when equipment doesn’t need it |
| Regulation and selection | Relieving or non-relieving; range close to working pressure | Port sizes across stages, and whether equipment needs oil |
These are the sources’ statements, not selection thresholds.
How to choose: when to look at a regulator, and when at an FRL unit
Based on public sources, the choice can be divided as follows (grouping the sources’ statements into four situations):
- Look at a regulator when: you only need to reduce pressure to a set value and hold it (Source 6); for self-lubricating equipment, a filter plus regulator can be enough (Source 2); check relieving or non-relieving, with range near working pressure (Sources 1, 3, 6).
- Look at an FRL unit when: you want filtering, regulation and lubrication in one set, treating the air supply in order (Sources 1, 2, 3, 4); or the equipment using the air needs lubrication (Sources 3, 4, 5).
- Points to watch: an FRL unit need not have all three stages — it can be filter and regulator only (Source 2); new pneumatic machines rarely use lubricators (Source 5), but Sources 3 and 4 also describe cases that still need them, so there is no single view (Sources 2, 3, 4, 5); filters do not remove water vapor (Source 3); of the 6 sources, 1 is a tutorial and the other 5 are makers or suppliers, with no neutral comparison and no standard text read; Source 2 says the three components can be used individually but doesn’t compare separate versus combined use.
- Near the boundary: the sources give no line for moving from a single regulator to an FRL unit; follow the equipment manual, air quality and site rules (Sources 2, 3, 5).
These are statements from public sources, not a conclusion for your site; which stages to install still depends on your equipment, air supply and operation.
How JIAHON can help:
- Regulator side: pressure regulators, precision regulators and pressure-reducing valves — please ask for each item’s port size, set pressure range, flow, accuracy and connections.
- FRL side (the site’s product name is FRL unit; lubricators and filter-regulators have separate pages): FRL units — please ask for port size, set pressure range, filter rating, drain type and whether a gauge is included; air lubricators — single lubricators, please ask for port size, bowl capacity and minimum flow; air filtration and pressure regulation series — filter and regulator components, please ask for port size, filter rating and set pressure range.
When you need to match a type, please prepare six items: supply pressure and flow; the set pressure range and port size you need; whether air is used by cylinders, air tools or valve manifolds; whether the equipment manual requires lubrication and which oil; site temperature, dust and humidity; and the model you use now and the problem you have. Please contact JIAHON.
Related reading
- “How to choose a pressure regulator”
Sources and limits
Sources: a pneumatics retailer’s tutorial (2021, Source 1); an industrial supplier’s page (2024, revised 2025, Source 2); a pneumatic parts company’s catalog page (2014, updated 2026, Source 3); an automotive repair trade magazine article written by a pneumatic equipment supplier (2021, Source 4); an industrial automation publication article by a supplier’s product manager (2017, revised 2025, Source 5); and a regulator maker’s page (revised 2024, Source 6).
Limits: five of six sources are makers or suppliers with promotional content; no neutral comparison or standard text was read. Figures such as 1 meter per second and 3 hertz are one source’s examples, not thresholds. This is not piping design; follow component specifications and equipment manuals.