can Shurflo pump 4008 partially fail?

[ssheriff]

I put a new Shurflo 4008 in my Granby last year. It now takes about twice as long to fill a quart bottle (48s/quart) than it did when new (23s/quart). The inlet filter is clean, I can blow air back into the holding tank so that seems unobstructed, and the faucet and shower filters are clean. So, does anybody know if these pumps can partially fail or have another idea about what's wrong?

 

[CougarCouple]

Hello sheriff
When you say you can blow back to the holding tank are you blowing thru the pump? I think there should be a check valve so I don't think you should be able to blow thru the pump. Their customer service is pretty good.

https://www.pentair.com/en/contact-us/residential-filtration-solutions-customer-service.html

Here is a trouble shooting guide"

https://www.pentair.com/content/dam/extranet/brochures-and-catalogs/product-manuals/shurflo/SF_PumpTroubleShoot.pdf

Russ

 

[Beach]

Kinked line?

 

[Wandering Sagebrush]

I suspect you have a restriction rather than a pump issue. Possibly a slight kink in the line, but more than likely a clog that clears when you blow out the lines, then is pushed back by the pump. It’s not uncommon to have plastic shavings left in the water tank after installation.

Is there a splitter/tee where the cold water is routed to the water heater? That could impact both shower and faucet. Since your filters appear clear, the next place I would look is where the water line connects to the bottom of the faucet, then at the aerator.

 

[ssheriff]

Thanks all, still working on it. The tank to pump line is not obstructed. I disconnected the pump's outlet and the pump works fine, looks like 3 gal/min. There are no kinks in the lines which are pretty stiff pex (I think). I removed the flow-restrictors at the faucet and at the shower. Curiously, for either if I turn the valves off, let the pump go until it stops,and turn on any of the four valves the initial flow is great for a few seconds then it reduces to a trickle while the pump cycles on /off. I've tried compressed air from the shower outlet back through the system after disconnecting the pump's outlet, that didn't help and nothing "weird" came out. Maybe I can rig a connector from the compressor to the faucet and try that too. Getting at the splitter/tee before the shower & faucet valves looks like it will require disassembling the whole cabinet. Anyone know any shortcuts?

 

[Wandering Sagebrush]

I dont know any short cuts, but it sure sounds like the pump is picking up stuff and clogging up the lines. You might try a call to FWC for ideas about getting to things.

 

[LAWNMOWERMAN]

I assume you have an inline filter/strainer?I have worked on many Shureflow diaphram pumps and most problems were from crap in the check valve or the flapper valves.Sounds like it is building up pressure so that might rule out the ckeck valve.The pump assy is real easy to take apart.Take care when reassembling.Plastic pump housing can crack from over tightening

 

[camelracer]

I had a similar problem a while back and it was caused by the crap that comes off the water heater anode plugging the faucet screen. I now clean the screen and flush the water heater regularly.

 

[CougarCouple]

Hi ssheriff

How long did you let the pump run when disconnected from the plumbing system I suppose you could have something in the supply line to the faucet. If it is restricted would have to be before it splits to all the faucets, if they are all behaving the same. I had debris in my pump and it would keep cycling when the faucet was closed, but didn't notice a loss of pressure. Sounds to me like the pump is starving, pumping against a closed line doesn't require the same volume of fluids as an open faucet does. If the pump builds pressure sounds like the pump is functioning, but it can't pump what it can't get. Good luck you'll find it.

Russ

 

[ssheriff]

I think I solved this. I tested the plumbing lines with compressed air, all seemed fine. Disconnected from the plumbing, the pump easily put out 3 gal/min. Once I reconnected the pump I could only get a trickle out of the facet or shower; this wasn't making sense. To experiment I tightened the pump's pressure switch until the pump wouldn't stop running when connected (~3/4 turn), water flow was great. I then backed off the screw bit by bit, testing the flow as I went. When I got back to the original position I was getting good flow again, filling quarts as quickly as when the pump was new. My best guess is that over the winter period, when the system was dry, the switch either got stuck or perhaps a bit oxidized. In any case, cycling the pressure switch screw seems to have solved the problem.

 

[CougarCouple]

Congrats ssheriff on figuring it out. Now that shower will get you wet, instead of leaving you wanting more.

Russ

 

[New Man]

As the poet said, "Pump won't work 'cause the vandals took the handle." This may be of some use to others grappling with the hopeless SHURflo user manual troubleshooting page [translated from what?!], FWC's troubleshooting PDF [useful, but no cigar for my problem], and the Wild West of Youtube.

Filled my tank, turned on the pump, pump ran continuously, but no flow. After much head scratching, checking intake and output lines [all clear], and puzzling over the aforementioned, I finally came across this video:

BINGO! Basically, there is a spring-loaded "check valve" [mentioned in one of the earlier replies to this] inside the plastic manifold on top of the pump. It opens and closes to alternate intake and output in the cycle. It can get stuck. When stuck, the pump runs, but neither draws water nor pushes it. When I took the manifold off the top of my pump, mine was stuck. All I had to do was push on the valve, and it freed and returned to its normal spring-loaded in/out operation. It seems it can get stuck from: 1) debris jam, 2) calcification [mineralized water drying up in the pump over time, especially sitting dry all winter], or 3) just plain crankiness [my problem?].

FWC really out to add this to their "Water Pump & Water System" PDF--a lot cheaper than replacing a perfectly good pump.

Of course you've got to pull the dang thing out and put it back into the hole they built around it, but thanks Mom and Dad, for giving me skinny arms!

 

[Vic Harder]

As the poet said, "Pump won't work 'cause the vandals took the handle." This may be of some use to others grappling with the hopeless SHURflo user manual troubleshooting page [translated from what?!], FWC's troubleshooting PDF [useful, but no cigar for my problem], and the Wild West of Youtube.

Filled my tank, turned on the pump, pump ran continuously, but no flow. After much head scratching, checking intake and output lines [all clear], and puzzling over the aforementioned, I finally came across this video:

BINGO! Basically, there is a spring-loaded "check valve" [mentioned in one of the earlier replies to this] inside the plastic manifold on top of the pump. It opens and closes to alternate intake and output in the cycle. It can get stuck. When stuck, the pump runs, but neither draws water nor pushes it. When I took the manifold off the top of my pump, mine was stuck. All I had to do was push on the valve, and it freed and returned to its normal spring-loaded in/out operation. It seems it can get stuck from: 1) debris jam, 2) calcification [mineralized water drying up in the pump over time, especially sitting dry all winter], or 3) just plain crankiness [my problem?].

FWC really out to add this to their "Water Pump & Water System" PDF--a lot cheaper than replacing a perfectly good pump.

Of course you've got to pull the dang thing out and put it back into the hole they built around it, but thanks Mom and Dad, for giving me skinny arms!

Great first post! Welcome to the cult!