Built to Outlast.
Engineered to Outperform.
Built to Outlast.
Engineered to Outperform.
Most sewer jetters on the market use a conventional triplex pump. Harben doesn’t. Harben builds its jetters around a proprietary radial piston diaphragm pump for its reliability, durability, and lowest cost-of-ownership.
Generally, both kinds of pumps do the same thing when sewer jetting. If you’re comparing specifications, the numbers also look similar. The real difference is the cost-of-ownership of the sewer jetter over years, or even decades.
A triplex pump creates pressure using three plungers that move back and forth through seals and packing. As those plungers cycle, they pull water into the pump and force it out at high pressure. It’s a proven design that has been used for decades and remains common across many pressure-washing, industrial cleaning, and sewer jetting applications.
The challenge is that components wear constantly from working against one another, creating heat and friction. Packing, seals, and valves, and, in some cases, plungers wear out on a regular basis. None of this means a triplex pump is a bad design. It’s simply how the pump works. The water side and the mechanical side are closely connected.
Triplex pumps are really well-suited for applications where extremely high pressure is needed. That’s why you’ll often find them in industrial cleaning systems running pressures far beyond what most sewer contractors regularly need.
A radial piston diaphragm pump takes a completely different approach. Inside the pump, pistons move in a circular pattern around the crankshaft. Instead of those pistons contacting water directly, they flex diaphragms that transfer energy into the pumping chamber. The biggest difference is that the water side and the mechanical side of the pump are separated. The pistons never contact the water directly, and there are no ceramic plungers moving through packing and seals thousands of times per minute.
That separation reduces the wear points that drive routine maintenance in conventional triplex pumps. Instead of relying on packing and seals to contain pressure around moving plungers, a simple diaphragm acts as a barrier between the pumping mechanism and the water itself. It’s a completely different build.
A radial piston diaphragm pump is designed to provide strong pressure, high flow, long service life, and reliability for daily use by sewer contractors. When compared to the conventional triplex pump, the reduced wear components, run-dry capability, and long-term reliability are key advantages for both contractors and municipalities.
Every operator knows they shouldn’t run a pump dry. But every operator eventually has a day when it happens anyway. It doesn’t matter why it happens, but when it does, it’s a real problem for the pump.
Triplex pumps need water for cooling and lubrication around critical sealing surfaces. When flow stops, heat builds quickly. That simple mistake can quickly damage packing, worn seals, and create an unexpected repair bill. Owners know crews aren’t as diligent with machines as they would be, and the run-dry protection is just another way to protect the jetter from damage.
A radial piston diaphragm pump is designed to tolerate running dry. Most owners hope they never need that protection, but the day eventually will come when something doesn’t go according to plan. When it does, that extra margin of protection is a safeguard that owners appreciate.
Every pump has wear parts and will need maintenance and rebuilds. The difference is how often you’re replacing those parts and how much downtime comes with the process. A triplex pump has multiple parts that wear during normal operation. While it’s not always expensive, the downtime adds up whenever a sewer jetter is in the shop, not in the field.
A radial piston diaphragm pump has fewer wear components by design, so maintenance tends to be around diaphragms and valves rather than an ongoing cycle of packing and seal replacement. They last longer and the rebuild is simple, keeping the sewer jetter in the field longer.
The strongest advantage of a radial piston diaphragm pump isn’t necessarily that a repair is less expensive. It’s that repairs tend to happen less often, at longer frequency, making the machine far more reliable.
| Ownership Factor | Typical Triplex Pump | Harben Radial Piston Diaphragm Pump |
|---|---|---|
| Water Contacts | Plungers, seals, packing, valves | Diaphragms and valves |
| Major Wear Components | Packing, seals, plungers, valves | Diaphragms and valves |
| Run-Dry Capability | Limited | Excellent |
| Sensitivity to Operator Error | Higher | Lower |
| Vibration | Higher pulsation | Smoother operation |
| Maintenance Focus | Frequent wear-part replacement | Scheduled diaphragm service |
| Maintenance Events | More frequent | Less frequent |
| Warranty | Typically 1-2 years | 5 Years |
One of the easiest ways to understand the difference between these pumps is to look at the parts involved when maintenance time arrives. Manufacturers, including Harben, offer parts individually or as full kits to help owners keep parts in stock.
| Component | Typical Triplex Rebuild | Harben Pump Service |
|---|---|---|
| Packing | ✓ | — |
| High Pressure Seals | ✓ | — |
| Ceramic Plungers | Sometimes | — |
| Valve Assemblies | ✓ | ✓ |
| O-Rings | ✓ | ✓ |
| Diaphragms | — | ✓ |
The shop mechanics look at these systems side by side and usually understand the advantage pretty quickly. There are simply fewer parts to wear out in a radial piston diaphragm pump. That doesn’t mean a Harben pump never requires maintenance; it just means the maintenance schedule tends to be simpler and less frequent.
Everyone wants a precise number when they ask about service intervals. But like most things in this industry, the answer is: It depends. Water quality, operating pressure, maintenance habits, crew behavior, and type of work all affect pump life. What matters more is durability and how often the pump itself requires major attention.
A major rebuild on a triplex pump and a radial piston diaphragm pump costs about the same, once you factor in parts and labor. The real question isn’t what a rebuild costs. The question is how often you’re doing one.
Many triplex pumps require major service somewhere in the 100- to 200-hour range, depending on operating conditions and maintenance practices. Harben’s radial piston diaphragm pumps are designed for much longer service intervals, with major diaphragm service often measured closer to 1,000 operating hours.
In the 1,000 hours put on a machine, a triplex owner has to plan for multiple rebuilds. A Harben owner is more likely only doing inspections, preventative maintenance, fluid changes, and keeping the machine working before the machine needs major work. It’s about maintenance frequency more than maintenance cost.
Harben is the only manufacturer to offer the radial piston diaphragm pump, and it’s backed with a 5-year warranty. It’s the longest pump warranty in the sewer jetting industry and speaks to the pump’s design and durability.
If the pump needs constant rebuilding, offering a warranty like that wouldn’t make much sense. The 5-year warranty is there because Harben believes in the engineering behind the machine. It’s the same reason you’ll still find older Harben pumps working in the field decades after they were built.
Triplex pumps are good pumps. They’ve been around for decades, and there are applications where they’re absolutely the right choice. If your business or public works revolve around extreme pressure, a triplex pump makes sense.
Most sewer contractors aren’t doing that type of work. They’re trying to keep crews moving and trucks producing revenue. For those owners, the questions are more about which pump will spend the most time in the field? Which are being fixed or maintained more often? What will be the total cost of ownership in 10 years? For a plumbing business or a municipality, the radial piston pump is often the best investment.