Doseuro SDP Solenoid Pump: Reading the Specs for Drinking Water and Cooling Towers

Chlorinating a small water supply or feeding scale inhibitor to a cooling tower often takes just a few liters of chemical per hour. A motor-driven pump is overkill there, and that's the gap the Doseuro SDP solenoid pump is meant to fill. The question we hear most from buyers holding the data sheet is simple: why does one Doseuro SDP model list several flow and pressure figures? Let's start with that table.

What Kind of Pump Is the Doseuro SDP?

Most of the Doseuro metering pump range is motor driven, with worm gear boxes, plungers and diaphragms. The Doseuro SDP is the solenoid exception. The literature pitches it as a simple, reliable option for low flow, with a built-in microprocessor so that a handful of models can cover both constant and proportional dosing.

Common features across the series:

Corrosion-proof reinforced polypropylene housing, foot mounted;
Solid PTFE diaphragm;
IP65 protection;
Standard supply 230V 50/60Hz, with 24V DC, 12V DC, 24V AC and 110V on request.

Each Doseuro SDP ships with an injection valve, a foot strainer, and 1.5 m each of suction and delivery tubing, so a small job can go in straight out of the box.

Doseuro SDP Specs: One Hydraulic Code, One Curve

Liquid ends are identified by a three-digit hydraulic code: 115, 220, 507, 810, 154 and 203. Each code lists several flow and pressure pairs because the same pump delivers more as back pressure drops. Take code 115: about 1 L/h against 15 bar, rising to roughly 5 L/h at around 2 bar.

A few anchor points worth remembering:

Code 220 has the highest pressure, 20 bar at 2 L/h;
Code 154 still gives about 15 L/h at 4 bar;
Code 203 has the most flow, about 20 L/h at 3 bar and roughly 22 L/h at low pressure.

Every Doseuro SDP runs at 120 strokes per minute, with 2 m water column suction lift, 4/6 mm tubing connections, 37 W or 58 W power draw, and a weight of 3.5 to 4.1 kg.

The classic mistake is treating maximum flow and maximum pressure as one operating point. People see 20 bar and 22 L/h and assume one pump does both. They come from different codes.

So take the real pressure at the injection point and find the matching flow on the curve. Here's an example. A cooling tower loop injection point sits around 4 bar and needs about 12 L/h. Code 203 is rated at 3 bar, and the sheet gives no point at 4 bar, so we wouldn't promise it. Code 154 gives about 15 L/h at 4 bar, a little over two tenths more than needed, which is a sensible margin. Done that way, the code picks itself.

Choosing a Control Version

The same liquid end can be paired with different electronics, and the letters at the front of the model name tell you which.

Mostly manual duty

SMC is the analog version, with a potentiometer adjustable from 10% to 100% and a double scale. The US sheet also lists SML, which adds a level control port. SMM is digital, with a three-digit display, manual setting from 0 to 100% and a level probe input. For cooling tower top-ups or pools where the feed rate barely changes, either is plenty.

Following water flow or an instrument

SWM takes pulses from a flowmeter and offers pulse multiplication 1×n, division 1:n, and multiplication with memory 1×n–M. SSC accepts a 0–20 mA signal with a user-configured range. SSW has a 12×2 LCD and takes both pulse and current signals.

For drinking water disinfection proportional to inflow, a common setup is a water meter sending pulses to an SWM.

SMF with built-in instruments

SMF builds pH, ORP and chlorine measurement into the Doseuro SDP itself: 0–14 pH, −1000 to +1400 mV, and chlorine ranges of 0–2, 20 or 200 ppm, with 0–100 ℃ temperature compensation and a 4–20 mA output. Small pools and hydroponics, where nobody wants a separate controller, are a good fit. Note that level probes and electrodes are not included with any version.

Materials and Installation Traps

Wetted parts come in PP, PVC, PTFE and PVDF, and some sheets also list 316 stainless. In the standard combinations, code 02 is a PP head with FPM lip valves, while 29, 24 and 31 are PVDF heads with ceramic balls and differ in their seal kits. For hypochlorite or dilute acids, check head and seals against concentration and temperature. Valves and seals wear, so order a spare set with the pump.

Suction lift is only 2 m water column, so don't sit the tank too low. Hypochlorite gasses off, so a flooded suction with the pump below the liquid level works best. Cooling tower injection points are often at low pressure, where chemical can siphon through. A back pressure valve on the discharge steadies things a lot.

Is a Doseuro SDP the Right Choice?

The strength of the Doseuro SDP is a short model list with a lot packed in: manual, proportional and instrument-controlled versions in one series, with drinking water, cooling towers, pools, hydroponics, aquaculture and car washes all named in the literature. The limit is just as clear. Flow runs from a few liters to around twenty liters per hour and falls as pressure rises. Beyond that, you move to a motor-driven Doseuro metering pump.

Conclusion

Read the Doseuro SDP table by hydraulic code first, then use the real injection pressure to find the flow on that code's curve. Don't mix up the top pressure and the top flow. Pick SMC or SMM for steady feed, SWM to follow a water meter, SSC or SSW for a current signal, and SMF if you'd rather skip a separate controller. Watch the 2 m suction lift and fit a back pressure valve at low-pressure injection points, and the pump should run steadily.

FAQ

Can a Doseuro SDP take a 4–20 mA signal?

SSC and SSW accept current signals. The literature says the range is user-configured within 0–20 mA, and the common 4–20 mA falls inside it, but confirm the setup with your supplier when ordering. The manual SMC and SMM can't.

Which pump head should I use for sodium hypochlorite?

The literature lists material options but no chemical chart. A PVDF head with suitable seals is common, but check it against concentration and temperature. If you're unsure, send us the chemical details.

Can one pump feed two injection points?

We don't recommend it. Two points at different pressures means the chemical favors the lower one. A solenoid pump has little flow to split anyway, so give each point its own pump.

Is lower flow in winter normal?

Yes. Colder chemical gets thicker, suction resistance rises and output drops. Insulate outdoor tanks and lines, and recalibrate with a calibration cylinder when the season changes.

Is there a NEWDOSE alternative for a dozen or so liters per hour?

Yes. The NEWDOSE DFD, DP and DM series cover a similar flow band with manual, pulse and current control, so you can compare them against your duty.

To match a Doseuro SDP code and control version to your dosing point, or compare it with a NEWDOSE option, contact us.