If you’ve ever shopped for industrial pumps, you’ve probably run across OH2 type pumps somewhere in the mix. I’ve been supplying them for nearly a decade now, and one question I get asked more than any other is some version of: “Can an OH2 pump even work in a low-temperature environment?” It’s such a common query because low temps tend to mess with parts that other pump types barely notice, and nobody wants to sink money into gear that seizes up or breaks at the first sign of frost. Today I’m breaking that down with real-world context, not just textbook specs. OH2 Type Pump
First, let’s make sure we’re on the same page about what an OH2 pump actually is. API 610 is the standard that governs most centrifugal pumps used in oil, gas, chemical processing, and general industrial applications, and it categorizes pumps into types based on configuration. An OH2 is an overhung centrifugal pump—meaning its impeller, the part that moves fluid, hangs off one end of the shaft, and the drive motor is mounted separately, connected by a flexible coupling. That setup is popular because it’s simple to maintain, easy to access the impeller and seal, and lighter and cheaper than other overhung or between-bearing pump types. But that design simplicity also means it’s got some inherent weak spots when temps drop, especially if you’re using it outdoors or in unheated process rooms where things get frigid.
Let’s start with what “low-temperature environment” even means here, because that term gets thrown around a lot. For industrial use, a low temp can be anything below 32°F (0°C), the freezing point of water, all the way down to -50°F (-45°C) for extreme cold climates like northern Canada, Siberia, or high-altitude mining sites. A lot of people assume if a pump’s rated to operate at 32°F, it’s fine for -40°F, but that’s not how metallurgy and lubrication work. The biggest risk in low temps isn’t just the cold itself—it’s how it interacts with the pump’s components.
First, there’s the seal and lubrication system. Most standard OH2 pumps come with mechanical seals or gland packing that uses standard lubricants or seal flush fluids formulated for room temp. When temps drop below freezing, those fluids thicken, turn into a gummy or even semi-solid mess, and that makes the pump’s shaft spin harder than it should. That extra friction wears out seals prematurely, causes motor overload, and can even snap the coupling or bend the shaft if the cold is bad enough. I once had a customer in northern Minnesota call me in a panic in January 2019—they’d installed a stock OH2 pump for a water transfer line and it seized up solid at 12°F (-11°C) because the standard grease in the motor and the seal’s flush line had turned to a block of wax. We got a replacement unit rated for low temp out there in 48 hours, but that mistake cost them 3 days of downtime on a critical process line. That’s the kind of headache I see all the time when people grab a standard unit without checking the low temp specs.
Next, metallurgy expansion and contraction. Most stock OH2 pumps are made with cast iron for the casing and ductile iron for the impeller. Cast iron has good cold tolerance up to a point, but at temps below -20°F (-29°C), it becomes more brittle. If you’ve got a pump that’s being cycled between cold standby and operation, the repeated expansion and contraction of metal parts can cause tiny cracks in the casing over time. For non-critical applications like water transfer, that might just lead to small leaks, but for chemical processing or pumping volatile fluids, those cracks can turn into safety hazards. A lot of newer OH2 pumps for low temp use swap out cast iron for carbon steel or even alloy steels like 316 stainless, which retains its toughness at way lower temps. I always advise customers to ask about metallurgy when they’re looking at OH2 pumps for cold sites—don’t take the stock cast iron for granted.
That said, OH2 pumps aren’t just off-limits for low temp environments. I’ve supplied units to sites in Alaska, northern Quebec, and even a gold mine in northern Australia at 5,000 feet altitude where winter temps drop to -45°F (-43°C), and they’ve run flawlessly for years. The key is that you have to specify the right configuration, not assume one-size-fits-all. There are four main adjustments we make to OH2 pumps to make them work in low temps, and I work with every customer to walk through which ones they need for their exact application.
First is the lubrication and seal system upgrade. Instead of standard lithium-based grease, we use synthetic grease that’s formulated for low temp—synthetic lubricants stay fluid down to -60°F (-51°C) or lower, so the shaft spins freely even in the coldest conditions. For mechanical seals, we use seal flush fluids that are also synthetic, and we sometimes add trace heating tape to the seal housing and coupling area to prevent any freeze-up in lines that hold static fluid when the pump is idling. For standby pumps, we’ll even add a small circulation loop that keeps a tiny amount of fluid moving through the pump when it’s not in use, so there’s no chance of it freezing solid.
Second is the metallurgy swap. As I mentioned earlier, standard cast iron gets brittle at sub-zero temps. For low temp OH2 pumps, we use carbon steel casings and alloy steel impellers that are rated for down to -50°F (-45°C), and for sites with even colder temps, we can go to duplex stainless steel that works at -100°F (-73°C) and beyond. The cost difference between cast iron and alloy steel is about 15-20% for the pump itself, but the cost of downtime from a failed pump is way higher—any site operating in below-freezing temps can tell you that.
Third is insulation and heat tracing for the entire pump skid. A lot of customers overlook the fact that pump piping and the baseplate can get cold too. Even if the pump itself is rated for low temp, if the piping full of fluid freezes, it can put pressure on the pump casing and crack it. We work with our customers to add custom foam insulation around the pump, baseplate, and suction and discharge piping, plus heat tape on any lines that are prone to holding static fluid. For outdoor skids, we’ll even add a small weatherproof enclosure with its own heating element to keep the pump’s motor and control system from getting too cold.
Fourth is the control system adjustment. Standard pump controls might not account for slow startup in cold conditions. If the pump is started when its grease is still thick, the motor will draw way more amperage than it’s rated for, which can burn out the motor or trip the circuit breaker. We adjust the control panel to add a soft start feature that ramps up the motor’s speed over 30-60 seconds, giving the lubrication time to warm up and thin out before the pump is operating at full capacity. That small adjustment has saved more of my customers from premature motor failure than any other change we make.
Now, is there a scenario where an OH2 pump should not be used in a low-temperature environment? Sure. If you’re pumping a fluid that freezes solid at temps above -10°F (-23°C), like pure water that’s sitting in a line overnight, a standard OH2 pump isn’t going to work—you’d be better off with a submersible pump or a different centrifugal pump type that can handle thawed lines. But for most industrial applications, where you’re pumping a fluid that’s either already at operating temp and circulating continuously, or a fluid that doesn’t freeze at your site’s lowest temp, a properly configured OH2 pump works just as well in the cold as it does in mild climates.
I always tell customers to ask three key questions when evaluating an OH2 pump for low temp use: What’s the minimum temperature your site consistently hits? What fluid are you pumping, and does it freeze at that temp? Will the pump be running continuously, or sitting idle for long periods? The answers to those questions will tell us exactly what configuration we need, no guesswork required.
Take a recent customer of mine: a lumber mill in northern Maine. Their old pump was a standard OH2 that seized up twice a year, leading to 2-3 days of downtime each time, costing them about $15,000 per day in lost production. When they came to me, their site’s lowest temp is -18°F (-28°C), they’re pumping warm process water (so it never freezes while circulating), and the pump runs 24/7. We customized an OH2 pump with synthetic low-temp grease, carbon steel casing, heat tracing on the suction line, and a soft start control panel. Installed in 2022, that pump has run flawlessly for almost two years, no downtime related to cold weather. They just ordered a second one for their new processing line last month.
It’s important to distinguish between “can an OH2 pump be used” and “should an OH2 pump be used.” A lot of competitors will give you a one-word answer—no—if you don’t specify the right setup, but that’s because they’re selling off-the-shelf pumps, not customized solutions. As an OH2 pump supplier, I don’t push every customer to buy a customized unit if a stock one will work, and I don’t sell a stock unit for a job it’s not suited for. I’ve seen too many customers waste money on either overkill custom pumps that don’t need it, or cheap stock pumps that fail because they didn’t account for the cold.
If you’re working in a low-temperature environment and you’re looking for a centrifugal pump, don’t write off the OH2 type just because of horror stories from unconfigured units. The OH2 design’s simplicity and low maintenance make it one of the most reliable pump types for most industrial applications, and with the right upgrades, it performs consistently in cold climates just like it does anywhere else.
Whether you’re replacing an old pump in a cold location, specifying new equipment for a remote site, or just want to make sure your current setup is ready for winter, I’m here to help you get the right OH2 pump for your needs. Don’t guess at specs or assume one size fits all—reach out, tell me about your site’s lowest temps, the fluid you’re pumping, and how the pump will be used, and I’ll walk you through exactly what configuration will work best for you.
Mining Slurry Pump References
Hydraulic Institute. (2020). Pump Selection and Application Guidelines for Low Temperature Environments. API 610 12th Edition. American Petroleum Institute.
ASTM International. (2018). Standard Guide for Selecting Metallic Pump Components for Cryogenic and Low Temperature Service. ASTM A320/A320M-18.
Synthetic Lubricants Association. (2021). Performance Specifications for Lubricants in Industrial Pumps Operating at Sub-Zero Temperatures. SL-2021-003.
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