Water pump not picking up from tank on it's own

dfinn · 04-26-2015, 09:48 PM

Got a strange issue here that I could use a little help with. Not sure where to go with it.

My water pump won't pick up or prime from the tank on it's own. It's really odd. I've developed a trick to help it out and once it's going the water pressure is great but you turn the pump off and it loses it's prime and won't get it again on it's own. I pulled the inline filter off and cleaned it, it wasn't really dirty or clogged and it didn't make a difference when I put it back together.

here's a pic of the pump I have, it's a ShureFLO 200-210-39. I'm assuming this is what came stock from SMB

the trick that I've been doing to get the water pumping is to turn open the valve for the fresh water inlet coming in from the outside connection on the van, seen here:

and then unscrew the cap off of this water inlet hose (why is there an inlet hose inside the van, can't figure out why you'd ever want to use this?) and then blow into this. This forces the tank to pressurize which forces water to pump up and into the inline filter and eventually through the pump. Once it's gotten this far I close the water inlet valve pictured above and water pretty sure excellent. This process can be a bit of a pain and sometimes takes a few tries and a few minutes. It can be especially taxing after a few beers.

Any help or suggestions would be greatly appreciated as I'm really not sure what's causing this. It seems like my pump is good because pressure is great once it's gets going. Could there be a vacum leak or air leak somewhere causing the pump to just be sucking air when it's trying to get water?

**Gooseberry** · 04-26-2015, 10:19 PM

I would think it might be better if the pump was turned 180 and it did not have to pull the water up.

dfinn · 04-26-2015, 10:30 PM

Quote:

Originally Posted by Gooseberry

I would think it might be better if the pump was turned 180 and it did not have to pull the water up.

definitely makes sense although it would seem that with a 20 gallon tank there would be enough pressure from the water trying to push out of that pipe that it would feed itself up to the filter no problem. are most others mounted the opposite of mine? I'm under the impression that this is how it came from SMB but maybe not?

**Gooseberry** · 04-26-2015, 10:38 PM

Mine is closer to the bottom of the tank and more water above it. I thought that the filter had a one way valve? My pump has the filter on the bottom not the top.

dfinn · 04-26-2015, 10:45 PM

I don't think my filter has any one way valve, it seems really basic. It's just a metal screen inside there.

REF · 04-26-2015, 10:55 PM

Try removing that large fill tube and try plugging it at the valve with your hand, if that works, find a cap for it, esp since you don't use it, it may be that the pump is having to suck the air out of that thing before its able to prime itself.
I can't tell from the photo, is it drawing from the bottom of the tank, it looks like your water outlet is near the middle or top of the tank?

arctictraveller · 04-26-2015, 11:07 PM

I had the same problem. The rubber diaphrams inside the pump get hard and sometimes don't seal causing a loss of prime. Since the pump can't build a vacuum, water never gets to the pump cavity. When you pressurize the tank, you force water into the pump cavity which helps seal the valves and it starts moving water. You can get a rebuild kit, and it's easy to install. Another possibility is that the filter is cracked, allowing the pump to suck air. I broke mine trying to get it apart because it was really stuck together. West Marine sells replacement filters for under $5.00

86Scotty · 04-27-2015, 09:14 AM

I think REF and arctictraveller have your solution most likely. Mine became much harder to prime after I moved my tank to the rear (spare tire location) from below the seat right by the pump. Any extra water line slows things down, and of course seals, etc. do go bad. You could just replace the whole pump for less than $50 so you could try that if it's not simpler.

Just curious, you are trying to prime it with the sink off correct? I find that sometimes I have to turn the sink valve on/off/on/off to work some air out of the system. Ultimately it won't completely prime unless the sink valve is off (closed).

Viva · 04-27-2015, 09:27 AM

Quote:

Originally Posted by dfinn

(why is there an inlet hose inside the van, can't figure out why you'd ever want to use this?)

Side note, but to answer your question - at least as it applied to my 1997 SMB: On my rig the only outside fill was the "city water" connection, the one you hook a pressure hose to when you want water pressure and water coming from an outside source at a campground. Most RV's then have a separate "gravity fill" for when you just want to fill the water tank (and then disconnect and just use your internal tank/pump). On my SMB (and I think most others), Sportsmobile rigged up the city water fill connection to do double duty, presumably to avoid another hole in the side of the van. So, to fill the water tank from a hose, you connect said hose to the city water fill point, then turn that grey valve inside by the water tank, which "turns" the city water fill into a gravity fill and you can then fill your tank with a hose.

BUT, sometimes when traveling, you want to fill the water tank but don't have access to a hose. Or maybe the hose supply is not "good" water and so you want to fill from jugs I've also had it in small National Forest campgrounds that there is a water hose type supply, but it's not meant for RV's to use and so there is no way to get close to it. Then jugs work great as intermediaries. However, you can't really "push" jug water into that city water fill very easily.

Hence SMB provided the alternate inside fill. Mine was simply a threaded connection with a cap, and I made a short hose/funnel arrangement that I could attach when I wanted to fill via jugs. It looks like yours has a "permanent" hose attached (which looks fairly scuzzy, so I would want to replace the hose section - clear hose exposed to daylight gets that way, so you may want to use opaque hose, and/or make it removable so you store it dry/dark).

Anyway, it may be something you don't have a use for, but that's the purpose. When I first got my SMB there was just the threaded connection and a cap, and I didn't have the parts to connect to it, and I really wished I had as I made a long trip just not finding a hose bibb. Would have been nice to just be able to pour 5-10 gallons of jug water into the tank.

Viva

dfinn · 04-27-2015, 12:08 PM

Thanks Viva, that makes sense.

86Scotty, I have tried with the fawcett on and off, didn't seem to make a difference. I just ordered a new filter as mine does seem old and cracked. I'll try that as well as plugging the gravity inlet hose. If that doesn't work it will be time to look for a replacement pump. Any suggestions on a $50 pump? Most I've seen are closer to $100 but I'm also not sure what to get as a replacement.

Edit: shurflo was quick to respond. The 4008-101-e65 is a direct replacement. Got one through amazon for $70, hopefully the combo of new pump + new filter gets me all fixed up.