Jabsco Diaphragm Pump Not Priming

If your diaphragm pump won't prime you may have a small bit of debris caught in the head. Check out this video on how to disassemble the pump head to inspect the check valve assembly.

Jabsco Diaphragm Pump Not Priming 6:07

Jeff: Thanks for watching jabscotech.com. I'm Jeff Lander.

Mike: And I'm Mike Irving.

Jeff: And today we're going to talk about a diaphragm pump not priming.

Mike: Now the big thing about these pumps is there's little check valves in there and if a little bit of debris gets behind that check valve, it's not going to allow the pump to prime because it just can't build up pressure in the head. We got one from the field; I haven't taken it apart yet. We’re going to walk you through how I do it. What do you say?

Jeff: Let's do it, Mike.

Mike: So, I got my handy dandy trusty 5/16-inch nut driver on my cordless drill makes life a little bit easier and you can either use a popsicle stick or a like a dental pick. I usually use the round side of it. Be careful of the pointy side because it's rubber components in there and you don't want to damage any of the components. So let me show you. This is how we take it apart.

One keynote don't take these all the way out and I'm going to show you why in a second. Just slide this right off. There's a diaphragm kit right there. Little check valve assembly. Inside there you can actually see one’s loose. There's a little pop-in or kind of like a seal. If you slide these bolts all the way out there’s a chance that you might lose one of those seals, so just back them out until they stop unthreading and make your life a little bit easier.

Now the check valve assembly there's five check valves, one big one in the middle and four on the underside. And I can almost tell you right now, I see where there's an issue. If you look real close, let me get a flashlight; can you see that right there, Jeff? See how that corner’s popped up on the inside? I see where the pump accidentally sucked up a little piece of wood – either wood or plastic. What I'm going to do is I'm going to pull that up a little bit. See right inside there? That piece of wood.

Jeff: There it is.

Mike: Even the slightest bit of debris will cause a pump not to prime, so just for giggles we'll take that flashlight, we’ll look in all the other valves. Flip it over and check out these valves here. It looks like we're good to go. It's worth noting that on top here there is an O-ring. Make sure that's seated properly in the recess and it's not damaged. We'll just go ahead and put that back in. And looks like we should be good to go on this one.

On the cover assembly, we'll make sure those pockets are down. The big valve goes towards the front of the head. Put it in. And this really isn't that difficult. I wouldn't be afraid of doing it. During reassembly there's a little arrow on the pump head; that's which way the water flows. At the factory we assemble them so that they're on the right-hand side if you're looking at the pump head. Don't tighten it all the way down at first. So, there you go. We found this itty-bitty little piece of wood in that’s going to make it so that the pump doesn't prime, and hopefully when we reattach this pump to the power supply, it will suck up water.

Mike: So, we're back. We talked about the Quad pumps – the square ones. The Triplex, the triangular ones, have a set of three intake diaphragms on them; they actually use Phillips head screws and you can actually back those all the way out. On these ones don't back them all the way. It'll make your life a little bit more difficult. Just go until they stop unthreading. The Triplex ones you can back them out all the way and take them right out. But checking the check valve assembly is actually quite similar. Just going through with a flashlight, maybe some blunt object to get underneath the valves, but if you're having a hard time priming, hopefully it's just a little bit of debris. If the pumps old or you accidentally pump some sort of like chlorine or anything like that, you might go ahead and swap out the check valve assembly. Check out the data sheet tab for the model number that's written on that pump and pick up the check valve assembly at your local marine store.

Jeff: Yeah, Mike, that was a pretty helpful video. So, thanks for that and thanks for tuning in to another episode of jabscotech.com. I'm Jeff Lander.

Mike: And I'm Mike Irving.

Jeff: Come back soon; we’ll have some more videos for you.