Projects are revised
Changed signal requirements, actuator arrangements and control designs can leave purchased relays outside the final installation scope.
Surplus industrial pneumatic instrumentation
Sell surplus pneumatic relays.
Move idle control inventory forward.
Unused air relays. Duplicate instrumentation spares. Volume boosters for a system that has been replaced. We work with companies looking to sell excess industrial pneumatic relays.
Discuss your surplus pneumatic relays →Start with complete model codes, quantities and clear nameplate photos.
How surplus develops
The control strategy changes.
The spare relays often remain.
Pneumatic relays perform defined functions with air signals, such as increasing flow capacity, changing signal relationships or selecting between inputs. When instrumentation platforms or process requirements change, the stock held to support them can become excess inventory.
Systems are upgraded
Replaced control equipment, redesigned valve packages and retired processes can release pneumatic relays and associated maintenance spares.
Stocking is consolidated
Duplicate purchases, preferred product changes and shared instrumentation programs can reveal more inventory than your operation requires.
Confirm with maintenance and instrumentation personnel which units remain necessary for active systems, planned work or internal redeployment before releasing stock.
Identify the actual function
Pneumatic relay inventory worth discussing.
We welcome inquiries about individual air relays, volume boosters and identifiable assemblies. These functions are model-specific; complete codes and documentation establish what you have.
Volume boosters
Signal-controlled units providing greater output flow capacity. Include the documented signal-to-output relationship and any bypass or adjustment options.
Ratio relays
Units with a specified or adjustable relationship between signal and output pressure. Record the exact model and documented ratio range.
Biasing relays
Relays applying a defined positive or negative pressure offset. Identify the actual function and available adjustment information.
Reversing relays
Units with a documented inverse relationship between input and output. Preserve range, setup and calibration records where available.
Selector & computing relays
High- or low-signal selectors and relays performing documented signal combinations. Include the function, port labeling and technical sheets.
Special-function relays & accessories
Identified snap-acting, lock-up or other relay designs, plus mounts and related components. Describe special functions only when documented for the exact unit.
Recognizable products. Exact identification.
Start with the manufacturer.
Keep the complete relay code.
Fairchild and ControlAir offer identifiable pneumatic relay and volume booster families. Have these products or other documented industrial air relays? Include them in your inquiry.
Fairchild / Rotork · ControlAir
Other manufacturers and legacy units are welcome. Brand names identify equipment only; Pneumatic Relays Depot does not claim manufacturer authorization, endorsement or affiliation.
A similar housing can perform a different function.
Model options can distinguish signal ranges, output behavior, materials, port arrangements and flow capacity. Identification is more useful than an assumed function.
- Copy all prefixes, suffixes and option codes.
- Photograph labels and port markings.
- Record supply, signal and output details separately.
- Preserve adjustment and calibration records.
- State which specifications remain unknown.
Condition and completeness matter
Separate unused spares from removed relays.
Sealed stock, opened unused units and equipment removed from service should be described separately. Share known use, storage conditions and maintenance or test records.
Disclose leaks, unstable output, sticking, damaged threads, corrosion, missing adjustment parts and modifications. A clean exterior does not establish signal accuracy or functional condition.
Keep mounting parts, gauges and documentation associated with the correct unit. Identify what is included in each assembly.
Keep specifications in context
Flow amplification and pressure amplification are different.
A volume booster may increase available flow while maintaining a specified pressure relationship. It should not be assumed to multiply pressure unless that function is documented for the model.
Record supply limits, signal ranges and output behavior separately. Share manufacturer data rather than inferring performance from port size or body dimensions.
Preserve the original control context.
Existing diagrams and setup records can help identify a relay’s role. Include them when available and state when calibration or settings are unknown.
Do not infer safety functions from a relay name alone. Application suitability, testing and removal should be evaluated by qualified personnel against the specific device and system requirements.
From excess inventory to an inquiry
Start with the stock you already have.
An existing list, partial export or readable photos can establish the starting point. Be clear about what has been counted, identified or tested.
Confirm genuine surplus
Check active systems and instrumentation spares. Select excess quantities and relays no longer required for current or planned installations.
Group and identify
Sort by complete model code, count quantities and note condition. Keep records and accessories with the right units.
Discuss selling the lot
Share the details, location and timing. Inventory fit, commercial terms and packing or transport requirements are confirmed for the specific stock.
A realistic view of resale potential
Value depends on the specific inventory.
Potential resale value depends on identification, function, configuration, quantities, condition, completeness and demand. A recognized brand or high original purchase price does not guarantee an offer.
Preserve the details that distinguish the lot.
Retain labels, packaging, manuals and available calibration records. Avoid grouping similar-looking units as identical without checking full model codes.
A clear surplus review helps purchasing and maintenance distinguish required instrumentation from stock tied to retired processes.
Common questions
Selling surplus industrial pneumatic relays
Can I inquire about used air relays?
Yes. Describe prior service, why they were removed and any known faults. Include photos and available records. Used or untested condition needs to be considered during review.
Can I include volume boosters?
Yes. Identify the exact model, documented signal-to-output relationship and supplied options. Do not assume every booster has the same pressure ratio or flow capacity.
What if I do not know the relay function?
Start with readable model labels, port markings and overall photos. Share existing documentation and state which details are unknown rather than guessing.
Can I submit a mixed lot of legacy instrumentation?
Group by exact model where practical and provide quantities and overview photos. Identify incomplete or uncounted items clearly. A partial list is a useful starting point.
Are calibration records required to begin?
No. Share any records available and state when calibration status is unknown. Do not represent a unit as calibrated or ready for service without supporting evidence.
Is there a minimum quantity or guaranteed purchase?
Share the inventory you have. Whether a transaction makes sense depends on the units, quantities, condition and logistics. Any offer or commercial arrangement is confirmed after review.
Put idle pneumatic instrumentation on the agenda
Have pneumatic relays your company no longer needs?
Unused project stock, duplicate spares or a larger control equipment lot — start with the details you have.