How to Read a DIFFUL Solar Pump Model Number: The 2DPC/3DPC-3DSC/4DSC-6DSC/8DSC Ladder Explained

The short answer: every DIFFUL solar pump model number is its own spec sheet, read left to right as body diameter, series, flow, head, voltage, power. A name like 4DSC9.5-90-110-1500 compresses five real decisions into twenty characters — it fits a 4-inch well casing, it is a DC solar submersible with stainless-steel impellers, it moves up to 9.5 m3/h, lifts up to 90 m, runs a 110 V DC system, and draws 1,500 W. Learn to read that string and you can shortlist a pump from a WhatsApp message without opening a datasheet — and, more importantly, you can see the catalogue’s logic: not 1,045 unrelated products, but a ladder with a rung for every water depth, flow demand and budget, from a 200 W garden set to an 18.5 kW irrigation machine. This guide walks that ladder rung by rung, with every model and number verified against the live catalogue.

One number, one choice: the anatomy of a model name

Take 4DSC9.5-90-110-1500 apart field by field:

Two suffixes you will meet: -A/D means the controller accepts an AC grid or generator input in addition to solar, and (HV) marks a wide-voltage model (our 3DSC4.8-95-110-750-HV, for instance, accepts 80-430 V). The catalogue currently lists 1,045 models: 537 with the A/D suffix and 210 wide-voltage HV variants — the A/D path is not an exception, it is half the catalogue, and by the time we reach the 6DSC farm machines it is the only path.

Three reading rules the field order forces on you, all of them real physics rather than marketing:

• Flow and head fight each other. The two numbers in the middle of the name are the two ends of one curve, not two simultaneous promises. 4DSC9.5-90 means the pump can do 9.5 m3/h, and it can do 90 m — it does both at the same time only at one duty point in between. Where that point sits is what the pump curve is for, and our how-to-read-a-pump-curve guide walks it line by line.
• The diameter field is a geometry gate. A 3D... pump goes into a 4-inch casing. A 4D... pump does not — not because of the printed number but because the cable, safety rope and any casing joints need clearance. Measure the casing before you fall in love with a model.
• The power field sizes your panels, not your expectations. Our spec sheets state the panel array rule directly: at least 1.3 times the pump power. A 1,500 W pump wants roughly a 2 kW array; an 18,500 W machine wants 24 kW or more.

The first fork: plastic impeller (DPC) or stainless steel (DSC)

The letter pair after the diameter digit is the single most consequential choice in the name, because it decides how the pump ages in your water.

DPC — plastic impeller. The entry rungs: 2DPC (3 models, 24-48 V, 200-400 W) and 3DPC (23 DC models, 200 W to 1,500 W). Plastic stages are lighter, cheaper and quiet; in water with no sand they last as long as anything else in the system. The 3DPC range also climbs impressively — 3DPC3.8-180-110-1500 lifts to 180 m — so “plastic” does not mean “toy”.

DSC — stainless-steel impeller. The workhorse rungs: 3DSC (13 DC models, up to 6 m3/h and 135 m) and 4DSC (28 DC models, from 4DSC3.5-50-48-400 at 400 W to 4DSC4.8-203-110-1500 lifting to 203 m). Stainless shrugs off the abrasive load that sand puts on impeller vanes — the wear that slowly thins plastic stages until both flow and head sag year after year.

The honest decision rule is one sentence: match the impeller to the water, not to the budget. A developed borehole in stable rock pumping clear water into a rooftop tank is a DPC job, and paying for stainless buys nothing there. A newly drilled well, an alluvial aquifer with fine sand, or any borehole that pumps sandy water after flood season is DSC territory, because one motor rewind or one re-drill costs more than the whole stainless premium. We keep a full comparison with wear photographs in the plastic-vs-stainless-steel impeller guide.

The ladder itself: every rung from 200 W to 22 kW

Here is the catalogue as its engineers actually built it — one representative model per rung, all verified in the live product table:

Read down the example column and the design philosophy shows itself. Below 1,500 W you choose freely between plastic and stainless, DC-only and A/D. From the 6DSC upward the catalogue turns industrial: 26 six-inch models spanning 5.5 kW to 22 kW (6DSC130-130-380/520-22000-A/D tops the range at 130 m3/h x 130 m), every one of them A/D, because a machine this size is bought by people who cannot afford a cloudy week — and exactly one 8-inch model, the 11 kW 8DSC150-37-380/520-11000-A/D, which moves a river — 150 m3/h is 2,500 litres every minute — through a modest 37 m of head, for the big-canal and estate duties where flow, not height, is the whole job.

That asymmetry is the catalogue telling you something true about water itself: small power buys height cheaply; large flow is only available at low height, and it costs real power. Physics sets that trade, not the price list — which is why the first number to fix in your head is never watts, it is total dynamic head.

The 3-inch / 4-inch boundary, in practice

The diameter digit is a hard geometric gate, and it splits at a duty point you can memorize:

• Stay 3-inch when the duty fits inside roughly 6 m3/h and 135 m. The 3-inch frame’s ceiling models are 3DSC6-115-110-1500 (6 m3/h x 115 m) and 3DSC5-135-110-1500 (5 m3/h x 135 m). A 3-inch body slots into a standard 4-inch (100 mm) casing with room for cable and rope — in much of Africa and South Asia, that is the casing already in the ground, and the 3-inch series is what keeps that asset usable.
• Go 4-inch the moment either number exceeds the ceiling. Need 9.5 m3/h at 90 m? That is 4DSC9.5-90-110-1500 — no 3-inch model comes close, because the impeller stack simply cannot be wider. Need 203 m of lift? 4DSC4.8-203-110-1500 again has no 3-inch sibling. The 4-inch series holds 28 DC models plus a deep A/D/HV bench, and it needs a casing of about 5 inches (127 mm) or larger once the cable and safety rope are counted.

The expensive mistake is ordering a 4-inch pump for an existing 4-inch casing because the datasheet number matched. The pump arrives, the cable bundle takes the clearance to zero, and the machine stops at the depth where the casing narrows at a joint. Confirm inside diameter, not nominal size — the geometric details live in our borehole-diameter matching guide.

Beyond 1,500 W: why the big pumps all say A/D

Somewhere around 1,500 W the catalogue changes its mind about DC-only, and the reason is arithmetic, not salesmanship. Panels are sized at 1.3 times pump power, so the jump from a 1,500 W pump to the smallest 6DSC (5,500 W) means going from a 2 kW array to 7.2 kW — and a 7.2 kW array is a real construction project with mounting steel, an electrician and a roof or field to match. The buyer at that scale is an irrigator whose season has structure: planting weeks that must be watered, monsoon months that will be cloudy, a harvest date that does not move.

For that buyer, the A/D suffix is the whole product. It means the same controller that tracks the panels also accepts grid or generator AC — our 4/6DSC36-38-300-2200-A/D class runs 80-420 V DC from the array and switches to 300 V AC when the sky goes dark. You buy solar economics for the 90 percent of days that are clear and insurance for the 10 percent that decide your harvest. That is also why the entire 6DSC/8DSC range — all 27 models from 5.5 kW to 22 kW — is A/D-only: at that power, solar-only is a bet almost nobody should take, and the catalogue declines to sell it to you.

If your duty sits at the boundary — a 1,500-2,200 W pump where the worst month matters — the compromise exists one rung down: plenty of 4DSC A/D models (86 of them in the 4DSC AC/DC family) carry the same dual-source trick at small-farm scale. The controller logic behind both is explained in the solar pump controller guide.

Voltage and the panel rule: reading the last two fields together

The last two fields of the name answer two different questions that buyers constantly conflate. Voltage (110 V, 24 V, AC380/DC520) is how the array is wired. Power (1,500 W, 5,500 W) is how much water-moving work the machine does. The bridge between them is the panel rule our spec sheets print on every model: array wattage ≥ 1.3 x pump power.

The 1.3 multiplier is not a margin for marketing; it is the standing loss account of a real installation — panel temperature derating on a 40 °C afternoon, dust, cable loss, controller efficiency, and the fact that no array spends the whole day at its label output. Take a 3DPC5-45-48-500: 500 W pump, so 650 W of panels is the printed floor, and a sane builder installs 800-1,000 W so the pump starts earlier in the morning and keeps lifting through the afternoon trough. Take the 8DSC150-37-380/520-11000-A/D: 11,000 W pump, 14.3 kW floor, and in practice a 16-18 kW array — at which point the array is the biggest line item in the budget, which is exactly when the A/D fallback starts to look cheap.

One practical note that saves whole afternoons: keep panels on the voltage the name states. A 24 V pump fed by a 48 V-wired array, or a HV model pushed beyond its window, does not fail loudly — the controller simply derates or refuses to start, and the symptom looks like a pump problem. It is a wiring problem, and it is free to prevent.

What the ladder does to your budget

The model number is also a cost map, and its shape is worth seeing before you shop. Three gradients run through the catalogue at once:

• Along a series, price tracks power. Within 4DSC, the 400 W 4DSC3.5-50-48-400 and the 1,500 W 4DSC4.8-203-110-1500 differ by roughly 4x in motor, and the panel rule multiplies the difference again by 1.3 — total system cost tracks the last field of the name almost linearly.
• DPC → DSC is a modest premium, once. The stainless step costs more than plastic at the checkout and less than one motor rewind over ten sandy years. Where the water has any grit, this is the cheapest insurance on the ladder.
• DC-only → A/D buys a second source of electricity. The controller is more complex and the entry point of the big machines is higher — but compare it honestly against the alternative for a monsoon climate: owning and fueling a standby generator. The diesel arithmetic, with real numbers over ten years, is in our solar-vs-diesel cost comparison, and the full install-budget breakdown in solar pump installation cost.

The quiet summary: the name’s last field predicts your bill; the middle fields predict your satisfaction. Spend your comparison time on flow x head and impeller material, not on watts.

The verification habit: demand the curve, not the name

Here is the habit that separates a working installation from a disappointed one: the model number shortlists the pump; the curve picks it. Every name in this article carries a measured H-Q curve — flow on one axis, head on the other, and your system’s real duty point somewhere on the line between them. A 4DSC9.5-90-110-1500 is the right answer only if your total dynamic head sits near 90 m and your daily volume near 9.5 m3/h x several hours; at 45 m of real head the same machine delivers far more than its nameplate flow, and at 110 m it delivers far less than you hoped.

So the workflow I give every customer: read the name (you now can), find the model’s curve, mark your pumping water level plus friction on it, and check that the crossing point gives the daily volume you need. Ten minutes, no software — and it is the difference between the two 1,500 W machines in the FAQ above, one of which would flood your tank while the other starves it. If your duty needs extreme height, our high-head deep-well guide covers the 150-250 m band specifically.

And if you would rather not decode any of this alone: send me your water depth and daily need, and I will read the ladder for you. That is the entire reason the model names are printed honestly — so that a pump can be chosen on a message thread, verified on a curve, and still be lifting water in ten years.

Not sure which rung of the ladder is yours? Send me your well depth, water level and daily water target — I’ll match you to the exact model and its curve. Plug your numbers into the sizing tool, or reach me directly on WhatsApp.