Water hammer from my check valve
 

As the title says... I replaced my check valve with a swing type and now when I unplug the return pump I get water hammer at the valve wich makes it open and close repeatedly slowly letting water into the sump as it hammers.
Any suggestions?

To avoid hammering you want to avoid shutting off the water quickly. This could be as simple as putting a ball valve after your pump (never before!) and close it slowly before shutting off your pump. But you probably don't feel like this hassle...

You can also decrease the degree of hammering by limiting the straight pipe length before and after the valve. You can further disrupt the hammer effect by adding an elbow; this disrupts the propagation of pressure waves through water.

Yay Science!

Thanks for the advice Steve, I tried both of the solutions to no avail.
I did install a ball valve after the check valve (was going to anyway to adjust flow) and I also installed a 90 after the check valve but it did not affect it at all. The ball valve works but does not help for unexpected power outages or pump failure. Any other suggestions? Anyone? What type of check valves do others use?

Maybe a pic will help...Anything wrong with this setup?
http://i100.photobucket.com/albums/m...scaper/016.jpg

From what I've seen on these boards most people plumb without a check valve since they're prone to failure. They plan their sump configuration to handle the extra water from the overflow and piping when the pump is shut off or if there is a power failure. Again, this is what I've seen in other threads, not my experience since I'm currently running a sumpless system.

+1 Good advice.

OK I realized this a long time ago...kinda obvious, but I am not going to drain my tank, take it off the stand, pull the sump out, build another bigger sump.......

+1 ?? thanks for the help:rolleyes:

Ok, a couple things that might help here:

a) Check the orientation of your check valve. Depending on the type of check valve you have in there it it might have to be mounted horizontally (ie. swing-type check valve). I see a vertically mounted check valve, so look into that.

b) You can by non-water hammer check valves. Google it, buy it, put it in, Bob's your Uncle.

c)Failing all of that, mount the check valve horizontally and put an expansion chamber before the valve. Don't go and buy one, just make if from some PVC. Again, google has some good info on how to do this. It's an easy operation.

That's all I've got for useful tips. Soon I might have to join the "You should have just plumbed without..." group .... Just kidding!

Let us know how it goes and let's see if we can't fix this.

Thanks for the suggestions Steve!! The check valve is a swing type and says it can be used vertically but maybe that is the problem. I will try this horizontally as I am re-doing my plumbing for a new pump anyway.

Would anti-siphon holes drilled in the plumbing just below the water level line in your tank work to stop your system from completely draining into the sump in the event that your return pump stops running?

Thats all I've got to offer. I dont believe in band-aid solutions in any situation. Fix the underlying problem then you and your tank will always be much better off for it.

My apologies, I didn't see anywhere previous in the thread where you mentioned that it was not feasible to run without the check valve due to your current sump size.

No apologies necessary. My fault for lack of information.
You are totally right whatcaneyedo my mistakes in the start are a pain in the a$$ now and I will have to break it down and do it right, but it has to wait till after the holidays at least. For now...band aid.

OK you guys got me thinking, maybe I could go with no check valve if I can reduce the amount of water backflow into the sump by raising my return outlets...hmmm

Yes...that is what you need to be thinking about to eliminate the check valve.

Here is the type of Check Valve I use this
http://www.bulkreefsupply.com/store/...lve-tu-112.jpg

I have it mounted horizontally and it works perfect........I needed one cause Having anti syphon holes on a dart with a single outlet would spray water all over the place and when I placed them lower in the water then my sump would overflow so I had to go with a check valve.

Thanks for the info Kevin....as far as this problem goes it's on the back shelf now since I just cracked my sump!:mad:

As a quick fix.. you could change out the elbow above the checkvalve for a Tee, and put an arrestor above it. if you really want a quick fix you could even just drill and fill it in. Any building supply store generally has them, they're used for basement faucets, toilets, washing machines, stuff like that. They come brass or plastic, washing machine ones are generally plastic, and only run you about $20-$30 (yeah a lot for a chuck of plastic with an air cushion behind it). Also noticed the double elbows for what looks like power cord access, this could be the main problem of the water hammer, if you take that out while fixing your sump just throw a flexi pipe for the corner and you might dodge the problem completely. Anyways, good luck with the sump :D

I use this check valve as well and mine hammers right now. It did not on my other tank though. It must be a plumbing problem I made the return higher in the tank with a flex line so it only hammers for a bit now untill the water drops.

re
 

yeah, that sounds like it would work. if you drill a hole right below the waterline (the lowest point of water that can be drained without overflowing the sump) the hole will let in air cutting the siphon...

hey man you can always use a piece of foam to allow the air to get in and still have the water get defused alot.

exactly and try to dril a hole on a angle if you can. and drill it on the back of the pipe so if it does spray it will hit the tank and not go out front.......

Well after replacing the sump glass I decided to go with in sump return and I installed the check valve horizontally, it only hammers a couple times then stops.

Ah, there ya go! Not perfect but better that nothin'!