
Unique Flap Valve Pump for Handling Large Solids
The Crest Debem Fullflow 502 is a unique pump, designed to stand apart from traditional models. Unlike classic pumps with ball valves, the Fullflow 502 is equipped with flaps, allowing it to handle larger solids while minimizing the crushing typically associated with ball and cage systems.

While the Fullflow 502's ability to handle solids up to 45mm in diameter is not unique, its standout feature is its ability to accommodate solids up to 600mm in length.
Additionally, the pump incorporates an exclusive, patented circuit positioned below and perpendicular to the fluid chambers, rather than being aligned with the axis. This design ensures that solids move outside the pump casing, following a linear path at a lower level, reducing any potential obstruction.
The pump offers a maximum flow rate of approximately 530 litres per minute.

THE CREST PUMPS LIFETIME GUARANTEE
No matter how old your pump becomes, in the unlikely scenario that you have a problem, our engineers will be on hand to diagnose the issue and help you get up and running again.That’s why, with Crest Pumps you’ll never need to worry about unplanned downtime again.
Talk to us now to discuss your chemical pump requirements or book a free site audit to see how much time and money you could save!
The true cost of your pump
Upfront costs are just the beginning—did you know energy and maintenance make up most of a pump’s lifetime cost? A Life Cycle Cost (LCC) analysis breaks down these expenses, showing how small changes can lead to big savings in efficiency, running costs, and carbon footprint.

Technical Specification
FULLFLOW 502 |
|
Suction / delivery connections | G 2" 1/2 f o DN 65 |
Air Fitting | G 1/2 "f |
Max. Flow rate | 530 l/min |
Max supply air pressure | 4 bar |
Max. Head | 40 m |
Max negative suction head - dry running | 3.5 m |
Diameter max suspended solids | 45 mm |
Max length of solids | 600 mm |
Frequently Asked Questions
A diaphragm pump is a type of positive displacement pump which uses a flexible diaphragm as the only moving part to create pressure and move fluid. It is typically used in applications where a low flow rate, high pressure, or a pulsating flow is required.
A centrifugal pump is a type of rotodynamic pump that uses a rotating impeller to create pressure and move fluid. It is typically used in applications where a high flow rate ir required.
An air operated double diaphragm pump also known as an AODD pump is a type of positive displacement pump which operates using compressed air instead of an electric motor. It consists of two flexible diaphragms connected by a shaft, which move back and forth to create suction and discharge cycles.
As compressed air enters one chamber, it pushes the diaphragm outward, forcing fluid out of that side whilst simultaneously drawing fluid into the opposite chamber. A set of check valves ensures that liquid flows in only one direction. The air supply then shifts to the other chamber, repeating the cycle and maintaining a steady flow.
AODD pumps offer versatility, as they can handle a wide range of fluids, including abrasive, viscous and corrosive liquids. They are self-priming and can run dry without damage, making them ideal for unpredictable flow conditions. Additionally, they feature a simple design with minimal moving parts, leading to low maintenance and easy repair.
Yes, they can run dry without damage, making them ideal for applications with variable flow or intermittent fluid supply. Unlike centrifugal pumps, which can overheat and fail without liquid, AODD pumps use air pressure to move diaphragms, allowing them to operate safely even when dry. However, while they won’t suffer immediate damage, prolonged dry running can increase diaphragm wear, so regular maintenance checks are recommended.
Trusted By The Best































DON’T JUST TAKE OUR WORD FOR IT
Very good company with a wealth of expertise.