Which self-priming pump do you need? That depends on your application, the medium, the required flow rate and the head. In this article, you walk through the key selection criteria step by step, see which Gorman-Rupp series suit which situation and learn which mistakes to avoid.
Step 1 — Determine your application and medium
Start with the question: what are you pumping and in what environment? The composition of the medium determines which pump type and material of construction you need.
Ask yourself these questions:
- What is the medium? (clean water, wastewater, sludge, process water, chemicals)
- Does it contain solids? If so: what is the maximum particle size and what solids handling capability is required?
- What is the temperature of the medium?
- Is the medium corrosive, abrasive or viscous?
- Are you dealing with a constant inflow, or interrupted (so called snoring operations)
For wastewater with solids (solid handling pumps), a pump with high solids handling capability and a clog-resistant design is essential. For clean water or process water, a standard configuration may suffice.
Step 2 — Calculate required flow rate and head
The duty point of the pump is determined by the required flow rate (in m³/h or l/s) and the total head (in metres). The head comprises the elevation difference between source and destination plus the friction losses in the piping.
Do not forget the suction conditions: what is the suction lift and what is the NPSHa (available)? A self-priming pump can operate up to a certain suction lift, but that limit depends on the pump type, the medium and the ambient conditions.
Need help determining your duty point? The G.R.A.S.P. Pump Selector at grpumpseurope.eu helps you get started quickly.
Step 3 — Choose the right pump type
Self-priming pumps come in different configurations. The choice depends on the severity of the application:
Wet self-priming: the pump retains a liquid reserve in the pump casing with which it can re-prime when interrupted. Suitable for applications with limited suction lift and regular use.
Prime assisted (dry self-priming): an external vacuum system evacuates air from the suction line. Suitable for demanding conditions, long suction lines or applications where the pump must prime frequently.This type of pump is also the optimized choice when dealing with an interrupted inflow (so called snoring operations)
Read more about the difference between dry and wet self-priming in the comparison article.
Overview of Gorman-Rupp series by application
| Series | Type | Typical application |
|---|---|---|
| Super T-Series® | Self-priming, solids handling | Wastewater, sewage, construction, industrial applications with solids |
| Super U-Series® | Self-priming, high efficiency | Municipal wastewater, WWTP, process water, clean and dirty water |
| Ultra V-Series® | Self-priming, heavy solids handling | Sewage with wipes/fibres, heavy wastewater applications |
| PA / PAH / PAV Series | Prime assisted | Construction dewatering, emergency pumping, HDD |
| S-Line (mobile diesel) | Pump set | Temporary dewatering, emergency pumps, HDD, sewage bypass |
| E-Line (mobile electric) | Pump set | See S-Line, used in noise-/emission-sensitive areas |
View the full overview of self-priming pumps on the product page.
Common mistakes in pump selection
1. Only looking at purchase price.
The TCO, including maintenance, energy and downtime, is a better measure. Read more in the article on costs and TCO.
2. Underestimating suction conditions.
Excessive suction lift or insufficient NPSHa leads to problems with priming or cavitation. Always check the suction conditions of your installation.
3. Not verifying solids handling capability.
Choose a pump with sufficient free passage for the solids in your medium. Undersizing leads to clogging and downtime.
4. Forgetting maintenance access.
A pump that is difficult to reach costs more in maintenance and downtime. Think about service access in advance.
When to involve a pump specialist?
For demanding or complex applications, such as varying flow rates, high suction lifts, corrosive media or integration into existing systems, it pays to involve a pump specialist early. Gorman-Rupp Europe offers selection support and system analysis to determine the right configuration.
Share your application details (flow rate, head, medium, solids, installation) and we will advise the right configuration.
Need help with pump selection? Request obligation-free advice from our pump specialists.
