Hey there, it’s Jake from your go-to pneumatic & electric diaphragm pump supplier, and let’s be real—most of you guys (whether you’re a maintenance tech at a manufacturing plant, a field engineer fixing process systems, or a shop owner stocking spares) have probably stuck a pump in a corner of the warehouse, kicked it when it wouldn’t work later, and gone, “Ugh, why’d that break so fast? It was brand new!” Pneumatic & Electric Diaphragm Pump
Yeah, I’ve heard that a hundred times. And half the time? It’s not that the pump was faulty out the box—it’s that you didn’t store it right when it wasn’t in use. I see this all the time: folks yank a pump off a job, leave it sitting in a damp garage, forget to blow out the fluid lines, and a few months later, it’s seized up, rusted, or the diaphragms are all weird and cracked. That’s such a waste of good equipment, and I’m here to save you from that headache.
Whether your pump’s sitting idle for a week because you swapped it out for a new run, or it’s gonna stay in storage for months (say, a backup unit for a plant shutdown), there’s a right way to prep it. And no, you don’t need a fancy climate-controlled lab—just a little know-how from someone who’s been selling these things for 7 years, troubleshooting in your plants, and learning the hard way when I messed up storing a demo pump last year. Let’s break it down, no fancy jargon, just what actually works.
First up—let’s split this into two big groups, because pneumatic and electric diaphragm pumps are totally different beasts. I get a lot of questions where people mix them up, and that’s half the problem. Pneumatic ones run on compressed air, right? They’ve got air motors, no electronics really, but they use a ton of small moving parts that can get gunked up. Electric ones? They have motors, wiring, maybe even circuit boards—way more sensitive to moisture and dust, so storage hits different here.
Let’s start with the quick-storage scenario first—like, the pump’s only gonna be idle for a few days to a couple weeks. Maybe you pulled it to clean a line, or a spare just sitting till your current one craps out. This is simple, but easy to skip.
First step for ANY pump (pneumatic or electric) when you take it offline: drain all the fluid. I don’t care if it was pumping water, chemicals, oil, whatever—leftover fluid is enemy number one. If it’s a corrosive chemical? That’ll eat through the inner housings or diaphragms in a matter of weeks, even if you can’t see it. If it’s water? That’s gonna rust every metal part inside. I once had a customer bring in a pneumatic pump that’d sat for 3 weeks pumping mild detergent—they just drained the “obvious” liquid, left a tiny puddle in the bottom, and when they tried it, the check valves were so gunked up with dried detergent it wouldn’t prime.
For draining: take the pump to a proper disposal spot if the fluid’s hazardous, or just flush it with the same fluid it ran with (or a compatible, non-toxic stuff like isopropyl alcohol for water-based fluids) until it runs clear. Then blow out all the lines with compressed air—low pressure, like 20-30 PSI, not the full shop air that’ll tear seals. For small internal passages, if it’s a pump you use often, I’ll even toss a little dry air through it for 10 seconds to make sure every drop is gone.
Next, disconnect all the connections. For pneumatic pumps: unplug the air line, cap the air inlet and outlet ports right away. Dust, moisture, even bugs can get in there and mess up the air motor. For electric pumps: disconnect the power cord, tape up the exposed terminals with electrical tape so moisture can’t seep in, and cover the motor shaft if it’s sticking out (some electric pumps have a drive shaft that’s exposed—don’t leave that uncovered, it’ll get rusty). Also, wipe the whole pump down with a clean rag—get rid of any oil, grime, or fluid on the outside; that stuff can attract dirt and hold moisture against the metal.
For short-term storage (days to a month), that’s pretty much it. Stick it on a clean shelf, not on the concrete floor (concrete sweats moisture, trust me), cover it with a plastic sheet or a cardboard box to keep dust off, and you’re good.
Now the big one: long-term storage. That’s when the pump’s gonna sit 2+ months, maybe even a year, unused. This is where I see 80% of the mistakes happen. I’m talking backup units for when your main pump goes down, or units you bought for a future project that’s delayed. Don’t just toss it in the back of the warehouse and forget about it—do these steps, and that pump’ll run like new when you pull it out.
Again, split pneumatic vs electric here, because they handle long storage totally different. Let’s do pneumatic first.
For pneumatic diaphragm pumps: after you drain and flush (like short-term), here’s the extra step. Most of these have diaphragms, right? If you leave them dry or exposed to certain chemicals, they’ll crack or get brittle. I recommend putting a light, food-grade (or pump-grade, no weird stuff) silicone lubricant on the diaphragms and all the rubber seals. Not too much, just a thin coat—think like the amount you put on a car door hinge. Why? Because it keeps the rubber flexible, prevents it from drying out and cracking. Also, before you cap all ports, blow a tiny bit of compressed air (again, low pressure) through the pump to keep the inner cavity slightly pressurized—wait, no, not super pressurized, just enough to keep outside moisture from getting in. Then cap every single port with the plastic caps that came with the pump, or if you lost them, use clean rubber stoppers. Don’t leave any ports open—even a tiny gap lets humidity in, and humidity over months will rust the internal valve parts.
Also, for pneumatic pumps with air filter regulators? Empty the water from the regulator, make sure it’s dry, and cap that too. Those regulators hold a lot of moisture if you leave them closed, that’s a hidden issue.
Now electric diaphragm pumps—these are way more finicky for long storage. The motor is the main enemy here. Moisture can get into the windings, cause corrosion, even short out the circuit board if your pump has variable speed or anything electronic. First, same initial steps: drain all fluid, flush, blow out, disconnect power, tape terminals. Then, here’s what you need to do for the motor: if it’s a submersible electric pump? Wait, no, even non-submersible—take off the motor end cap if it’s easy (don’t force it, check your manual if you’re unsure) and use a small fan to blow dry, room-temperature air through the motor windings for 15 minutes. If you don’t wanna take the end cap off, you can also put a small desiccant pack (the ones you get with new shoes or electronics work, no need for fancy industrial ones) inside the motor housing, taped securely so it doesn’t move around. That’ll absorb any moisture that’s in there.
Also, for electric pumps with exposed shafts? Like I mentioned earlier, oil the shaft lightly with the same silicone lubricant, then cover it with a plastic cap. And don’t forget the control parts—if your electric pump has a switch or a circuit box, make sure that’s sealed off. Maybe wrap it in plastic wrap before putting the whole pump in storage, so no dust gets in there.
Now, where you store the pump matters just as much as what you do to prep it. I see people leave pumps in the corner of the warehouse where it’s damp next to a loading dock, or on the concrete floor. That’s a no-go. The ideal storage spot is a dry, cool place—temperature between 50-75°F (10-24°C), low humidity (under 60% if you can get it). If you don’t have a climate-controlled spot, don’t panic—just avoid the super obvious bad places. Don’t put it on concrete (concrete releases moisture overnight, especially in colder months). Put it on a wooden pallet, a metal shelf, even a stack of clean wooden crates. Keep it away from windows where direct sunlight can hit it—sunlight breaks down rubber and plastic parts over time, even if they’re not in use. And keep it off the floor, away from where forklifts or cleaning staff might bump into it—damaging a pump in storage is just another waste of money.
Wait, one thing I get asked all the time: “Can I just leave the diaphragm pump connected to a hose or line?” NO. Even for short storage, that’s a bad idea. Hoses can crack, lines can build up moisture, and if the hose’s full of fluid, it’ll seep back into the pump and cause issues. Always disconnect all hoses, drain them too, and store them separately (coiled loosely, not tight, so they don’t kink).
Another pro tip from someone who’s been there: label your stored pumps. Write down the date you put it in storage, what fluid it was last pumping, and whether it’s pneumatic or electric. I’ve had customers come to me saying “I have a pump in storage, what is it?” and they have 5 units with no labels. Saves you so much time when you need to pull a backup for a job.
Wait, what about if you’re storing brand new pumps that never even been used? A lot of my customers order extra spares and store them for a future project. That’s similar, but a few tweaks. For new pumps, don’t take off any of the factory packaging unless you have to—most of them come with protective plastic on ports and seals, which is meant for storage. If you do open it up, still do the short or long-term prep steps, depending on how long it’s gonna sit. And keep the original box if you can—it’s made to protect the pump during storage, way better than a random garbage bag.
Let’s talk about common mistakes I see all the time, to make sure you don’t do ‘em. First mistake: skipping draining the fluid. I can’t stress this enough. A customer last year pulled a pump that was pumping caustic soda, just wiped the outside, and stuck it in a corner. 6 months later, the entire inner manifold was corroded through, like someone had eaten a hole in it. Total waste of a $1,200 pump. Second mistake: using too much lubricant on the rubber parts. Too much silicone will attract dust, which gets into the pump when you take the caps off. Third mistake: storing in a hot, damp garage or basement. I’ve had a customer store a backup pump in their heated garage over the winter, but the garage is next to a pool area—humidity was 70% all winter, and the motor seized up. Fourth mistake: leaving ports open. Even a tiny gap lets moisture in, and over time, that’ll rust the internal valve components, which are super hard to fix without replacing the whole pump.
Now, what about when you pull a stored pump out to use it? Don’t just hook it up and go. Give it a quick check: wipe it down, make sure all ports are still capped (don’t forget to take the caps off, that’s a common “oops” moment), check the diaphragms for cracks, spin the pneumatic air motor a little by hand to make sure it’s not seized, or spin the electric motor’s shaft (if it’s not wired) to make sure it turns smoothly. If it’s been a long time since storage, maybe flush it with a little clean fluid before hooking up to your main line to make sure no debris is inside.
Look, I get it—you’re busy. You’ve got 100 other things to do, so spending 15 extra minutes prepping a pump for storage feels like a waste. But here’s the thing: a good diaphragm pump is a workhorse, if you take care of it. I’ve seen pumps last 10+ years when they’re stored right, but I’ve also seen ones die in 6 months just because they were left sitting wrong. It’s not magic, it’s just small steps that add up.
If you’re in the market for new pneumatic or electric diaphragm pumps, or you need a replacement part, or you’re just not sure how to store yours properly—hit me up. I’ve got 7 years in the game, I’ve worked with every type of pump, every industry from food and beverage to mining, and I can help you get the most out of your equipment. No pressure, no sales pitch that’s too pushy—just a guy who knows pumps, and wants you to not waste your money like so many others do.
Happy pumping, and don’t forget to treat your stored pumps like the valuable tools they are.
Pneumatic Diaphragm Pump References:
- Pneumatic Diaphragm Pump Storage Guidelines, National Fluid Power Association, 2021
- Electric Diaphragm Pump Maintenance Handbook, Pump Manufacturers Association, 2022
- Industrial Equipment Storage Best Practices, Occupational Safety and Health Administration (OSHA), 2020
DEPAMU (Hangzhou) Pumps Technology Co., Ltd.
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