One of the biggest hits at this year’s Milwaukee Tool New Product Symposium—from the plumbing department—was the new, self-priming M18 Transfer Pump. The Hub shot a Facebook Live video from the event and received more than 8,000 views within the first couple of hours of seeing a demo for the first time.
Our ProStaffers were chomping at the bit to get their hands on one, so we sent it out to Bob ‘Hot Rod’ Rohr; Andy Mickelson, owner, Mickelson Plumbing & Heating; and the Hub’s Eric Aune, owner, Aune Plumbing LLC, for testing and review.
According to Rohr, the pump is well built and has nice fit and finish. “If weight—7.9 lbs.— equals quality, and the tool is properly used and maintained, this should be a coveted, long-lasting tool,” says Rohr. Aune and Mickelson agree, “The pump is lightweight compared to typical transfer pumps used on the job—cast iron usually,” says Aune.
“The weight is a big plus, as we are frequently packing our equipment though a house. This unit easily fits in a 5-gallon bucket with hoses for transportation,” says Mickelson.
The pump has a nice balance when carrying and using with one hand. Yet, says Aune, while the carry handle protects on/off switch, the handle makes it somewhat difficult to access the button. Rohr’s solution? If you hold the tool with your right hand, index finger towards the battery, “I found you can use the tip of your thumb to activate the switch. This frees up your left hand, and allows one-handed operation.”
The battery is protected under a hinged, tight fitting cover. Warranty is a generous—5 years. Performance on 5.0 battery, washer hoses, draining 50-gal H2O heater, for instance: 12 minutes—that’s fast, would be faster with larger hoses. Runtime on 9ah battery increases by almost 2x. “When paired with the 9.0 battery I see this being a very versatile tool, providing an exceptional run time for a cordless tool,” says Mickelson.
And, no additional cord to plug in is added value and makes jobs easier/faster.
Rohr says that he did not see any pump curve information included in the box. The spec sheet indicates 18’ maximum lift and up to 75’ head, or about 35 psi. (144 gallons per battery charge, about 20 minutes.)
The pump does run much louder when it is pumped dry, indicating it is time to power it down. Milwaukee indicates not over 10 seconds of dry run. The pump should shut down after 1 minute of dry run, via the battery technology.
Rohr considers the pump a flexible impeller style of pump, a design around since 1800s. Some refer to this style as a positive displacement-style pump also. Mickelson continues that even with mild system back pressure the pump does not spin backwards when turned off, acting as check valve almost. And Aune says that the impeller is replaceable. If left to run dry, it will need replaced at some point.
What about glycol? The instructions mentions clear water use only—note the 140°F maximum fluid temperature—so check with Milwaukee regarding glycols or GEO fluids. It is rated only for water but Aune Plumbing has pumped straight undiluted glycol and rinsed pump without problem. Mickelson pumped thick cold glycol with the pump and had great results thus far. “Perhaps if the pump is flushed with clear water after use this will be acceptable. Milwaukee mentions flushing with clear water should ‘anything but clear water be accidently pumped.’ For plumbing and HVAC use it needs to be able to handle the typical, clean heat transfer fluid, in my opinion,” says Rohr.
If you want full performance from this pump, I’d suggest a 5/8 or 3/4” hoses, says Rohr. I did need to use a pliers to get a new hose to seal tightly, the threads seem a bit tight, time may wear these in so hand tightening is all that is required. Aune did notice some issues with the connections. “The hose fittings are odd in that some of my hoses will not tighten properly without wrench and effort,” says Aune.
Since the original posting of this review Milwaukee has taken our concerns about the hose fittings to the product engineering team for a solution. Effective immediately all new transfer pumps have been fitted with hose adapters that work with a wider variety of hose connections.
On the Job
Hot Rod perched it on top of a 6-foot ladder and pumped from an open 5-gallon bucket. The pump primed instantly, first time out of the box. My first test was with a common washing machine-type hose, about 3/8 actual hose inside diameter. The operation manual does suggest a ¾” ID hose.
It took just under two minutes to empty the bucket, with the restrictive, off-the-shelf wash machine hoses. Pumping straight out of the pump, no hose on the discharge.
He then switched to a hose with a full 5/8” ID and the bucket emptied in 37 seconds! So at 6-ft. lift, wide-open discharge I measured just under 8 gallons per minute flow rate.
His first job was to re-prime a siphon hose that fills a stock watering tank. The inlet end hose plugs with debris from the pond source from time to time. Rohr pumped clean water from a 5-gallon bucket into the siphon line to get the system flowing gain. This is one of the many tasks Rohr sees this cordless pump being used for around the shop.
Mickelson has flushed two tankless water heaters with this pump and he loves the self-prime feature. “The rubber impeller seems to be holding up nicely with the acid solution we use to clean the heaters. It also has shown no ill effects of pumping glycol or acid solutions.”
The techs at Mickelson Plumbing and Heating were able to pressurize a heating system with 33% propylene glycol to roughly 22 PSI with the pump. During this process we had pumped 30 gallons of fluid into the heating system, and purged the air out of the system with the pump for an additional 25 minutes, and the 9.0 battery still had 2 bars left on it!
• Rohr: This should be a homerun for Milwaukee Tool. With the versatile M-18 battery pack, this useful pump should find it way on many service trucks.
• Aune: Easily the handiest pump for cleaning/flushing tankless water heaters I’ve ever used. Slam-dunk design and performance for the money. It’s not inexpensive but fits perfectly within the M18 platform, which is very popular in the plumbing/HVAC trades
• Mickelson — This model, less the battery is less money than the current transfer pumps that we use. Will be buying more cordless versions very shortly.
Finally, for the HVAC contractor, Rohr suggests this as a transfer pump for filling or topping off hydronic, geothermal or solar systems. Plumbers may find it ideal for empting water heaters, assuming the drain cock is not plugged. If so add a PEX dip tube from the top of the tank to prevent pulling sediment from the bottom drain valve.
$179.00 for bare tool
$279.00 for kit
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