CO2 Incubator Regulator: How to Choose and Set One Up
Quick answer: a CO2 incubator needs a two-stage CO2 regulator with a CGA 320 inlet and a low delivery pressure range, set to the inlet pressure in your incubator manual. That setting is usually somewhere between about 4 and 29 psi. Our CO2 incubator regulator is built for this job. It is a Harris two-stage regulator with a needle valve and a 1/4″ hose barb, ready to connect to your incubator’s tubing. Call 888-641-2267 and we will match it to your incubator.
Why an incubator needs a CO2 regulator
Cell culture incubators hold CO2 at a set level, usually around 5%, to keep the pH of bicarbonate-buffered media stable. The incubator’s internal valve is built for low pressure only, which is why every CO2 regulator for incubator use is a low-pressure model. A full CO2 cylinder sits at roughly 700 to 800 psi at room temperature (NuAire’s manuals quote this range). The regulator drops that pressure to the few psi the incubator expects and holds it there.
Too much pressure can damage the incubator. Thermo Fisher warns that the Heracell VIOS valves may not close properly above 1 bar (14.5 psi). PHCbi warns that excessive pressure can make the gas lines inside the incubator come loose.
CGA 320: the CO2 cylinder connection
Carbon dioxide cylinders in North America use the CGA 320 valve outlet, so your regulator must have a CGA 320 inlet. CGA 320 seals with a flat washer, not a metal-to-metal seat. Fit a new washer at every cylinder change; a reused, flattened washer is a common source of slow leaks. Use a vapor-withdrawal cylinder. NuAire warns against CO2 cylinders with siphon (dip) tubes, which feed liquid CO2 that can damage the regulator. See our CGA charts for other gases.
What inlet pressure does your incubator need?
There is no single “incubator pressure”. Each manufacturer specifies its own range, so always follow the manual for your model. Here is what the current manuals say:
| Incubator (manufacturer document) | CO2 inlet pressure specified |
|---|---|
| Thermo Scientific Heracell VIOS 160i / 250i | 0.8 to 1.0 bar (11.6 to 14.5 psi); never above 1.0 bar |
| Eppendorf CellXpert C170i | Default 0.1 MPa (14.5 psi); range 0.05 to 0.15 MPa (7.2 to 21.8 psi); max 1.5 bar |
| PHCbi MCO-170AIC series | 0.03 to 0.1 MPa (4.4 to 14.5 psi), from a two-stage CO2 regulator |
| NuAire In-VitroCell series | Rated at 20 psig; do not exceed 25 psig |
| BINDER CB series | 2.0 bar (29 psi); must not exceed 2.5 bar (36 psi) |
The spread is wide: a BINDER setting is twice the Heracell maximum. Check your manual before opening the cylinder, and recheck the setting at every cylinder change.
Single-stage or two-stage for an incubator?
Use a two-stage regulator. Eppendorf, PHCbi and NuAire all specify one, and NuAire says plainly not to use a single-stage regulator because it “will not give a stable output at 20 psi”. A two-stage regulator reduces the pressure twice inside one body, so the low setting your incubator sees stays steady from a full cylinder to a nearly empty one. Harris describes its two-stage GP402 as maintaining “constant delivery pressure from full to near empty cylinder conditions.” For the full explanation, read Single-Stage vs Two-Stage Regulators.
Which delivery pressure range to choose
Pick a range whose top end comfortably covers your setting. Harris builds its two-stage GP402 and HP702 regulators in 0-15, 0-50, 0-125 and 0-250 psig delivery ranges.
- 0-15 psig fits incubators set at or below about 14.5 psi, such as the Heracell VIOS and PHCbi MCO-170AIC, but it is too low for a NuAire (20 psig) or BINDER (29 psi).
- 0-50 psig covers every manual listed above, which makes it the safe general choice for most labs.
Our CO2 incubator regulator has a 0-50 psig delivery range, which covers every incubator in the table above, and comes with a needle valve and 1/4 inch hose barb. If you need a different range, the Harris GP402 CGA 320 and HP702 CGA 320 are also available. Call 888-641-2267 to confirm the right range before you order.
Hooking up an incubator CO2 regulator: needle valve and hose barb
Our CO2 incubator regulator comes with an outlet needle valve and a 1/4″ hose barb (not pictured on the product page). A typical hookup goes like this:
- Secure the cylinder, then fit the regulator to the CGA 320 valve with a new washer and tighten it with a wrench.
- Back the adjusting knob out (counterclockwise) until it turns freely, then stand to the side and open the cylinder valve slowly.
- Turn the knob clockwise until the delivery gauge reads your incubator’s specified pressure.
- Push the incubator tubing onto the hose barb and secure it with a hose clamp. The barb takes 1/4″ ID plastic tubing; incubator inlet sizes vary by brand, so check yours.
- Open the needle valve to let gas flow to the incubator, then leak-test every joint.
The needle valve gives you a convenient shutoff at the regulator, so you can isolate the incubator without closing the cylinder.
Never run out: automatic changeover for two cylinders
A cylinder that runs dry overnight can ruin weeks of cultures. Our two-cylinder CO2 manifold connects a primary and a reserve cylinder. When the primary is empty, it switches to the reserve automatically, so CO2 keeps flowing to your incubator while you replace the empty tank. Its delivery pressure is adjustable from 0 to 50 psi, and a hose barb is supplied for the supply line.
CO2 safety tips
- Secure every cylinder to a wall, bench or cart so it cannot tip. Our bench clamp and wall bracket both include a strap.
- Leak-test every connection with soap solution or leak spray after connecting, and again after each cylinder change.
- Ventilate. CO2 is colorless and nearly odorless, and high concentrations can cause unconsciousness. BINDER and Eppendorf recommend good ventilation and a CO2 monitor or alarm.
- Frost on the outside of a CO2 regulator is moisture from the air. Harris notes that internal “freeze-up” is a problem at high flow rates, not at the small, intermittent flows an incubator draws.
CO2 incubator regulator FAQ
What pressure should I set my CO2 incubator regulator to?
Use the inlet pressure in your incubator’s manual. Current manuals range from about 4.4 to 14.5 psi (PHCbi MCO-170AIC), 11.6 to 14.5 psi (Thermo Heracell VIOS), 7.2 to 21.8 psi with a 14.5 psi default (Eppendorf CellXpert C170i), 20 psig (NuAire In-VitroCell) and 29 psi (BINDER CB).
What CGA fitting does a CO2 cylinder use?
CO2 cylinders use the CGA 320 valve outlet, which seals with a flat washer. Replace the washer at every cylinder change and leak-test the connection.
Do I need a two-stage regulator for a CO2 incubator?
Yes. Eppendorf, PHCbi and NuAire all call for a two-stage regulator. A two-stage regulator holds the low delivery pressure steady as the cylinder empties; NuAire warns that a single-stage regulator will not give a stable output at incubator pressures.
What delivery range should a CO2 incubator gas regulator have?
A 0-50 psig range covers the settings in all the major incubator manuals. A 0-15 psig range suits incubators that need 14.5 psi or less, but it is too low for models that run at 20 to 29 psi.
Can one CO2 cylinder supply more than one incubator?
Yes, as long as the pressure and flow are sufficient. Eppendorf notes that you must ensure adequate pressure and flow when more than one device shares a CO2 source. For continuous supply, a two-cylinder automatic changeover manifold switches to a reserve tank when the first runs out.
Can I order a CO2 incubator regulator from LabRegulator.com?
Yes. Call 888-641-2267 or contact us for a price and availability. Shipping within the US is a $35 flat rate by UPS Ground.
Get a quote
Tell us your incubator make and model and we will confirm the right regulator, delivery range and fittings. Call 888-641-2267 or use our contact form for a price. US orders ship UPS Ground for a $35 flat rate. Still comparing? Read our Regulator Buying Guide or the High-Purity Specialty Gas Regulator Guide.