HVAC and refrigeration equipment spans two very different sealing problems under one industry heading. On one side, chilled and condenser water circulation pumps run continuous, relatively conventional duty across commercial buildings and district cooling plants. On the other, industrial refrigeration — ammonia (NH3) and CO2 systems used in cold storage, food processing, and process cooling — involves refrigerants that are chemically aggressive to standard seal elastomers and, in ammonia’s case, present a genuine safety hazard if a seal leaks. A single “HVAC duty” seal specification doesn’t serve both ends of that range well.
At Leak-Pack Engineering, we design and manufacture mechanical seals for HVAC and refrigeration equipment — chilled and condenser water pumps, ammonia and CO2 refrigeration system pumps and open-drive compressors, glycol circulation systems, and cooling tower pumps — engineered around the specific refrigerant, temperature, and duty cycle of each application. Our engineering team works from your system’s actual refrigerant and operating parameters, consistent with ASHRAE refrigeration guidance, to recommend the right seal design and materials.
In refrigeration service specifically, seal selection depends heavily on what refrigerant the seal will actually contact. Ammonia is highly effective as a refrigerant but attacks many standard elastomers and certain non-ferrous metals, meaning a seal specified without ammonia compatibility in mind will degrade quickly — and because ammonia is toxic at relatively low concentrations, a seal leak on an NH3 system is a safety incident, not just a maintenance one. CO2 systems operate at much higher pressures than conventional refrigerants, particularly in transcritical operation, which shifts the seal specification toward pressure capability as much as chemical compatibility.
Low operating temperature adds a second dimension that’s easy to underweight. Standard elastomers can stiffen, lose sealing force, or crack at the temperatures common in cold storage and low-temperature process cooling, well before their rated chemical compatibility would otherwise be a concern. A seal validated for a refrigerant at room temperature isn’t automatically validated for the same refrigerant at -30°C, and treating the two as interchangeable is a common source of underperforming cold-chain seals.
The refrigerant landscape itself is also shifting under regulatory pressure. The Kigali Amendment to the Montreal Protocol is driving a global phase-down of high-GWP HFC refrigerants in favor of alternatives including ammonia, CO2, and newer low-GWP synthetic refrigerants — which means seal material compatibility that was a settled question for a given system a decade ago may need revisiting as facilities transition refrigerants. We build that forward-looking compatibility check into every refrigeration seal specification rather than assuming today’s refrigerant will be tomorrow’s.
HVAC and refrigeration facilities run equipment from commercial building services through industrial cold chain and process cooling, each with a distinct refrigerant and temperature profile. We supply seals across this full range:
As with other demanding industrial applications, these rarely present in isolation — an ammonia compressor seal typically has to resist the specific refrigerant chemistry, perform at low temperature, and do so with a much lower tolerance for leakage than a comparable water-service seal. We size the specification to all three together.
Below is a general guide to the materials we typically recommend by HVAC and refrigeration application. Final material selection is always confirmed against your specific refrigerant, operating pressure, and minimum operating temperature.
| Application | Seal Face Combination | Secondary Seal / Elastomer | Wetted Metallurgy |
|---|---|---|---|
| Chilled & condenser water pumps | Silicon Carbide vs. Carbon | EPDM | 316 Stainless Steel |
| Ammonia (NH3) refrigeration compressors | Silicon Carbide vs. Silicon Carbide | FFKM / PTFE (elastomer-free) | 316 SS / Duplex |
| CO2 transcritical systems (high pressure) | Silicon Carbide vs. Silicon Carbide | FFKM (Kalrez-type) | 316 SS / Duplex |
| Glycol / cold storage circulation | Silicon Carbide vs. Carbon | EPDM (low-temp grade) | 316 Stainless Steel |
| Cooling tower & condenser water (scaling) | Tungsten Carbide vs. Silicon Carbide | EPDM / FKM | 316 SS / Duplex |
Yes. We specify elastomer-free metal bellow designs for ammonia refrigeration systems, avoiding the standard O-ring secondary seals that ammonia is known to degrade over sustained exposure.
Yes. We specify seal arrangements rated for the higher pressures typical of CO2 transcritical operation, often paired with seal support systems for additional containment.
Yes. We select secondary seal materials specifically rated for your system’s actual minimum operating temperature, since standard elastomers can stiffen and lose sealing force at cold storage and process cooling temperatures well within their nominal chemical compatibility range.
In many cases, yes. Refrigerant compatibility is specific to the chemistry involved, and a seal validated for one refrigerant isn’t automatically valid for another — we recommend a compatibility review whenever a system transitions refrigerants, including moves driven by the ongoing HFC phase-down.
Yes. Our multi-spring seal designs are specified to resist the scaling and biological fouling common in open recirculating condenser water systems.
Yes. Our cartridge and metal bellow seal designs are engineered for retrofit onto most existing HVAC and refrigeration equipment, including as upgrades from seals underperforming under actual refrigerant or temperature conditions.
Lead times depend on seal size, material, and arrangement complexity. Given the product loss risk from a temperature excursion, we prioritize fast turnaround on cold storage and refrigeration replacement seals — share your seal drawing or system details with our team for a firm timeline.
Every HVAC or refrigeration system runs a different combination of refrigerant, pressure, and operating temperature, which is why we don’t work off a fixed catalogue selection for this industry — every seal we quote starts with your actual system parameters, including any refrigerant transition your facility may be planning. We’re happy to work alongside your facilities and process engineering teams to review seal specifications across an entire pump and compressor fleet, not just a single problem application.
Send us your pump or compressor specifications — refrigerant type, operating pressure, and minimum operating temperature — and our engineering team will recommend the right seal solution for your application. Explore our full range of mechanical seals by industry or send an enquiry directly.
download catalogue