Suction and discharge hose, strainers, fuel and water nozzles, swivels, breakaways and meters. Whether it moves fuel oil, water or waste, the side that pulls and the side that pushes are not the same product, and getting that wrong is why most pumps will not prime.
The Core Idea
One side pulls, the other pushes
Every transfer pump has two hoses on it and people routinely buy two of the same thing. They are not the same thing, and the reason comes down to which direction the pressure runs.
The discharge side is straightforward. The pump pushes, the hose contains the pressure, and any hose rated above what the pump produces will do the job. That is ordinary hose selection.
The suction side is the opposite problem. The pump is pulling, which means the pressure inside the hose is lower than the air outside it, and atmospheric pressure is trying to crush the hose flat. A suction rated hose has a helix wire wound through the wall specifically to hold the bore open against that. Without it, the tube folds shut the instant the pump starts and nothing moves.
A suction rated hose can generally be used on the discharge side. The reverse never works. If a pump has stopped priming and nobody has changed anything, the suction hose is the first place to look, followed by every joint on that side.
Suction Lift
How high can a pump actually pull?
Drag the pump up and down. The height between the liquid and the pump is the one number people underestimate, and it has a hard physical ceiling nobody can engineer around.
Well within range
Most transfer pumps handle this without complaint, provided the suction hose is properly rated and every joint on that side is airtight. At this height the hose and the fittings matter far more than the lift does.
Nothing gets near the theoretical ceiling. At sea level atmosphere can support roughly 34 feet of water and that is the absolute physical limit, but friction in the hose, the pump's own losses and any warmth in the liquid all eat into it. Most pumps manage somewhere around 20 to 25 feet in practice, and less on a long or undersized suction run. Check what your pump is rated for rather than assuming.
Two Sides
What each hose has to do
Suction side
Runs under vacuum, so the wall needs a helix wire holding the bore open. Every joint on this side has to be airtight, because the pump will happily pull air through a loose clamp instead of liquid through the hose. A strainer on the end keeps debris out of the impeller.
- Must have
- Helix wire, airtight joints
- Usual end
- Cam and groove, banded
- Common failure
- Collapse, or an air leak
Discharge side
Runs under pressure, so it needs a rating above what the pump produces and a cover that suits where it gets dragged. Length matters here too, since a long or undersized discharge run costs flow the pump has already worked to produce.
- Must have
- Pressure rating above the pump
- Usual end
- Cam and groove, threaded
- Common failure
- Abrasion from dragging
The Delivery End
Nozzles, meters and strainers
Dispensing nozzles
Automatic shutoff and manual nozzles sized to the flow and the fill point. A nozzle that sticks or fails to cut off is how a routine fill becomes fuel on the ground, so it is not the part to run past its life.
Water nozzles and guns
Delivery nozzles for site water, washdown and dewatering. Simpler than fuel equipment and just as worth matching to the flow rather than fitting whatever thread happens to be spare.
Meters and registers
Flow meters for delivery work where what leaves the truck has to be accounted for. Mechanical and digital, sized to the line and the flow rate rather than to the hose thread.
Strainers and foot valves
A strainer on the suction end stops debris reaching the impeller, and a foot valve holds the prime between runs so the pump does not start from dry every time.
Swivels
Let the hose rotate instead of twisting. Twist is what fatigues a delivery line at the fitting, so a swivel at the nozzle end is one of the cheapest ways to extend the life of the assembly.
Breakaways
Separate cleanly and seal both sides when somebody pulls away still connected. On any yard with vehicles and a dispenser, it happens eventually. See fleet fuel transfer hoses.
Who Buys Them
Fuel, water and everything between
Fuel oil delivery and tank transfer
Delivery trucks running residential and commercial routes, yards refuelling their own equipment, and tank to tank transfer. Hose, nozzle, swivel, breakaway and meter specified together so a replacement part does not quietly change what the assembly is rated for.
The compliance side of fuel work, including static continuity and inspection intervals, sits on fleet fuel transfer hoses.
Dewatering, washdown and waste
Contractors pumping out excavations, municipalities running sweeper and vac trucks, marinas and boatyards moving water around. Suction and discharge sets made up to the pump and the job rather than bought as a generic pair.
The wider hose ranges sit on industrial hoses, with the couplings on industrial fittings and adapters.
Before You Buy
Common questions
The suction side, every time. Check the hose is actually suction rated and has not collapsed, then check every joint on that side for an air leak, because the pump will pull air through a loose clamp far more easily than liquid up a hose. After that, check the lift height and whether the strainer is blocked.
Only if it is suction rated, in which case it works on both. Discharge hose on the suction side does not, because it has no helix to stop the bore collapsing under vacuum. Buying a suction rated pair costs a little more and removes the problem entirely.
Less than people expect. The physical ceiling at sea level is around 34 feet of water and nothing reaches it, because friction and the pump's own losses eat into the figure. Most pumps manage somewhere around 20 to 25 feet in practice, and less on a long or undersized suction run. Check what yours is rated for.
On anything pulling from an open source, yes. Debris reaching the impeller does damage that costs many times what a strainer does, and on a dewatering job the water is never as clean as it looks. A foot valve alongside it holds the prime between runs, which saves a lot of time on a stop-start job.
Yes, and it is the sensible way to buy them. Tell us the pump, what you are moving, the lift and the run lengths, and both hoses get built with the right construction and matching couplings so the set works together rather than being assembled from whatever was nearest.
Yes. Delivery and dewatering hose are consumables, and the failures cluster at the busiest time of year. We hold the specification on file, set stocking levels around what you go through and build spare sets ahead of the season rather than during it. Ask at either counter or through the contact page.
Get The Set
Tell us the pump and the lift
Those two, plus what you are moving and how far, decide both hoses and the couplings on them. Built as a matched set at either counter.