Although my primary RV is a travel trailer I also have a old pop up camper I use occasionally. It has a hand pump on the kitchen sink. There is simply a water tote below the sink with a 3/8 flexible line that you put into the tote. You pump up and down on the valve handle mounted behind the sink to pump up water and there is a pipe that shoots the water into the sink basin. It works good for what it is intended for. The problem is that after pumping the water that is still in the line will try and slowly siphon (fall) back down into the tote. You can even watch the pump handle move position as it does this. This causes a suction noise back through the pumps outlet above the sink. This is right next to my head as I'm trying to sleep at night. (it's really a annoying noise) There is no real way to cork off the end of the outlet. What I need is something to put in the line below the sink that will keep the water from trying to fall back down into the tote and therefore no more siphon at the valve. Sorry that I did not explain this well. Does anyone have a solution to stop the hand pump from siphoning back down into the tote below it ?

Sharkbite check valve will work fine. Very low open pressure an high resistance to return. Works with most 1/2" lines including lots of flexible lines. Bring a small piece of the tubing with you so you can make sure it works with your tubing.

Amazon, Home Depot both have 3/8 check valves which will do the job for you.

I don't think you want a check valve, because you do want it to drain back out. Otherwise you'll have a mess on your hands. Our old popup used to make a mess when we'd flip the sink over and fold down the canvas top. We used to put something under the sink before we flipped it over, but it wasn't a great solution.For yours, could you find a black rubber stopper the same size as the faucet opening and plug it up before you go to bed?

I added a check valve... But so long as the faucet outlet is far enough above anything it can suck up it's just a labor issue.Oh and it's not "Siphoning" back it's leaking back via the check vlave in the pump.

wa8yxm wrote:I added a check valve... But so long as the faucet outlet is far enough above anything it can suck up it's just a labor issue.Oh and it's not "Siphoning" back it's leaking back via the check vlave in the pump.If I remember correctly (been 45yrs ago) when my Dad had a slide in TC it used the same type of manual pump.With that type of pump, you must make sure you return the handle back to the prime/store position which if I remember correctly the handle was in the up position.Pulled the handle down would pump water out then you had to return the handle to the up position.. Failure to return handle to up position would result in the same issue the OP has, lost prime. Then you would have to go through repriming the pump..Can't find any instructions on these pumps to look at and verify correct position for storing so OP might wish to try storing in the opposite position they are currently using to see if it stops losing prime.Otherwise might be a bad built in check valve and replacing faucet or adding a check valve may fix it.

anti siphon device ? | Good Sam Community

QCMan
Nomad III
Oct 11, 2022
Sharkbite check valve will work fine. Very low open pressure an high resistance to return. Works with most 1/2" lines including lots of flexible lines. Bring a small piece of the tubing with you so you can make sure it works with your tubing.
ssthrd
Explorer
Oct 11, 2022
Amazon, Home Depot both have 3/8 check valves which will do the job for you.
dedmiston
Moderator
Oct 11, 2022
I don't think you want a check valve, because you do want it to drain back out. Otherwise you'll have a mess on your hands. Our old popup used to make a mess when we'd flip the sink over and fold down the canvas top. We used to put something under the sink before we flipped it over, but it wasn't a great solution.

For yours, could you find a black rubber stopper the same size as the faucet opening and plug it up before you go to bed?
wa8yxm
Explorer III
Oct 11, 2022
I added a check valve... But so long as the faucet outlet is far enough above anything it can suck up it's just a labor issue.
Oh and it's not "Siphoning" back it's leaking back via the check vlave in the pump.
Gdetrailer
Explorer III
Oct 12, 2022
wa8yxm wrote:
I added a check valve... But so long as the faucet outlet is far enough above anything it can suck up it's just a labor issue.
Oh and it's not "Siphoning" back it's leaking back via the check vlave in the pump.

If I remember correctly (been 45yrs ago) when my Dad had a slide in TC it used the same type of manual pump.

With that type of pump, you must make sure you return the handle back to the prime/store position which if I remember correctly the handle was in the up position.

Pulled the handle down would pump water out then you had to return the handle to the up position.. Failure to return handle to up position would result in the same issue the OP has, lost prime. Then you would have to go through repriming the pump..

Can't find any instructions on these pumps to look at and verify correct position for storing so OP might wish to try storing in the opposite position they are currently using to see if it stops losing prime.

Otherwise might be a bad built in check valve and replacing faucet or adding a check valve may fix it.
JRscooby
Explorer II
Oct 12, 2022
I have the same system in my pop-up. Leave it set for 5 minutes the pump/line drains back to tank. If it took long enough to make noise after I went to bed I would install a valve to let air in so would drain faster.
Yes, I know my pump should hold prime much longer, but we only use it for teeth and face before bed. The great thing is to winterize all I do is open tank drain.
Matt_Colie
Explorer II
Oct 12, 2022
Charlie,
This is a common issue on many small boats as well. I have cured it for several owners just by disassembling and cleaning the part of the pump. Most pumps could be disassembled easily, but some are service proof.
Matt
Gdetrailer
Explorer III
Oct 12, 2022
Matt_Colie wrote:
Charlie,
This is a common issue on many small boats as well. I have cured it for several owners just by disassembling and cleaning the part of the pump. Most pumps could be disassembled easily, but some are service proof.
Matt

They must have really cheapened them, we would prime the pump before leaving for a 3 week adventure every summer and the pump would hold the prime unless someone failed to return the handle back to proper position..

The one we had, was not self priming, had to hold a cup of water to the faucet and pump like mad to establish prime.. Was a real pain if you didn't have some water handy to get it to pump water again :S
LouLawrence
Explorer
Oct 12, 2022
I suppose this is an inappropriate or unnecessary suggestion, but couldn't you just replace the manual setup with a simple 12v pump and new faucet?
Caveman_Charlie
Explorer II
Oct 15, 2022
Thanks for all the responses. It give me things to try out.