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Iwaki Aquarium Water Pump Information

Reef Aquarium

Iwaki Walchem magnetic drive pumps will run longer, quieter and cooler than any traditional mag drive. Extraordinarily high efficiencies make WMD & MD the clear choice in almost every process, recirculation or transfer application. Choose standard alumina ceramic bearing material and polypropylene impeller or optional SiC (silicon carbide) and ETFE (fluoropolymer) for your most aggressive or highest purity requirement.

Unique internal Cooling Circuit- creates a positive, forced cooling path, lubricating bearing surfaces and actively purging gases & heat. Unique double bearing system allows cooling circuit liquid to continually "wash" front and rear radial bearings, extending bearing life.

Precision Tolerances- Pumps can be supplied with alumina ceramic or SiC spindles, bored, turned and highly polished. This precision machined spindle forms the center of the driven magnet. Substantially reduced hydraulic noise is a major feature of all WMD/MD impellers. Great pains are taken in the molding/finishing process to eliminate tangential misalignment.

Bearings/Thrust surfaces- High lubricity fluoropolymer bearings minimize mechanical losses typical of conventional mag drive pumps. High purity SiC radial bearings handle the most aggressive ultrapure chemistries. PTFE front thrust surface aids hydraulic balance and minimizes flashing. Large rear thrust surface guards against axial forces caused by cavitation or gas entrapment.

Drive magnet- Dynamically balanced barium ferrite drive magnets provide best magnet torque. Die cast magnet carrier creates a flywheel effect, which adds to the magnet safety factor.

Motor matching- Offering more standard motor/pump configurations than other manufacturers offer for tailored pump applications. Premium, high efficiency motors are used throughout the line. Totally enclosed, permanent split capacitor motors are compact, cool and economical. Tolerance to voltage variation without overheating and 50/60 Hz operation allow the product to be used in a worldwide market.

Reef Aquarium
Reef Aquarium
Performance Curve
Note - IWAKI RLT are Pressure Rated pumps designed to pump into pressure canister filters or any situation that can create back pressure. IWAKI XT models are for standard circulation such as return from wet/dry. The pressure models are also suitable for standard return.

X- High Flow Impeller casing
Z- Pressure Rated Design
T- Threaded
R- Hollow Spindle Design, sizes 15 and up
L- UL listed and approved motor

Reef Aquarium
Frequently Asked Questions

Can I run these pumps dry?
No, No, No, Never. The (W)MD series relies upon a liquid medium to lubricate the internal bearings. Without fluid in the liquid end, the ceramic and plastic parts rub together while rotating 3000 times a minute. If you need run dry pumps, please check out the MDH series.

What is the difference between MD and WMD?
MD stands for Mag-Drive. WMD stands for Walchem Mag-Drive. In an effort to lower the cost of the MD pump which uses a Japanese motor, Walchem developed the WMD series. The Japanese motor and cast aluminum adapter bracket were replaced by a domestic (Fasco) motor and a polypropylene adapter bracket. A WMD will match the Hydraulics for the MD series but will typically be a little bit longer in length. The motor specifications and life expectancy are identical.

Are these pumps UL/CSA/CE approved?
Yes, no and sometimes. Always consult your Iwaki Walchem binder for precise information but there are some rules of thumb you can use. WMD products are always UL and CSA approved but not CE approved. All 115 V MD pumps are UL approved but not usually CSA approved. Most MD 220 V pumps are CE approved. At time, UL and CE are in conflict, case in point, the color of motor lead wires.

Do you offer a submersible pump?
No. None of our MD/WMD pumps can be submersed. For OEM applications (500+ pumps) please call us.

My pump seems to be running hot?
The WMD series runs hotter than the MD series. A rule of thumb is that the pump should be hot to the touch but you should be able to hold your hand on it for about 5 seconds. All MD/WMD pumps are thermally protected to shut off once the pump reaches a critical temperature. There is an automatic reset.

What are the materials in contact with the fluid?
For the MD/WMD series the liquid end is glass filled polypropylene including an encapsulated inner magnet. The spindle is alumina ceramic and the bearings are Rulon (a fluoroplastic/ Carbon mix). For our MD/WMD-F (Fluorplastic) series, the liquid end is ETFE with Silicon Carbide (SiC) spindle and bearings.

What type of motors do you use and can I buy them elsewhere?
For our MD-6 through (W)MD-30 series, the motor type is Totally Enclosed Non-Ventilated (TENV). For our (W)MD-40 and above, the motor is Totally Enclosed Fan Cooled (TEFC). All but one model are Permanent Split capacitor motors. We use the best bearing available in motors of this type, sealed-for-life roller bearings. We custom manufacture all of these motors and they are specific to our product only. You can not purchase them elsewhere.

What is the minimum flow of the pump?
For pumps with a flow rating up to 10 GPM we recommend ¼ GPM. Pumps with a flow over 10 GPM we recommend ½ GPM. Keep in mind that the lower the flow through the liquid end the more heat that will be transmitted into the fluid from the bearings.

Can I mount these pumps vertically?
We recommend horizontal mounting but vertical mounting can be utilized up to size 40. A heads up position is preferred. Always be sure that flooded suction conditions exist when mounting the pump vertically.

Can I use these pumps outdoors?
Yes. We recommend that they be enclosed in a vented cabinet since the motors are not washdown duty and should not be exposed to rain. Keep in mind that if the fluid freezes within the pump it can crack the plastic components easily.

Can I get these pumps in DC Voltages?
DC motors are available for most models, especially in the 40 and below series. Minimum order quantity of 250 units usually applies.

How long will my pump last?
This question is the equivalent of "How long will you live?" There are many factors that decide both of these questions including care, work performed and accidents. We do warranty our pumps for one year, parts and workmanship. Typically, a MD/WMD pump in flooded suction, ambient temperature service, running continuously will last three to four years. Many of our customers enjoy 5+ years of service. See that section of our web-site for examples.


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