Without a check valve your pump keeps repumping water already removed from the basin. When the motor shuts off, the water remaininig in the discharge pipe flows backward and down the vertical section of the discharge piping system. Without a check valve the water runs back through the pump into the pit. When the switch is activated that same water will be pumping out of the basin again. When a check valve is installed, the water flowing backwards after the motor shut off hits the check valve gate which prevents the water from flowing back through the pump. The water that has flown backwards will sit above the valve gate until the pump runs again. If the check vavle gate was not in place, the motor would keep pumping the same water over and over again and will burn out. When the water flows backward it has a lot of force. It is this force that causes a slamming thud sound. This slamming hammer sound can be reduced greatly by installing a quiet check valve.
The following information will help you understand the purpose of a check valve, the different styles, how the styles compare, how to install them and how the differences in construction make some of them quieter.
Select a specific topic for check valve for sump pumps if you wish to read about the topic immediately. Otherwise scroll down the page to see all topics.
One-way valves. All check values for sump pumps are one-way valves. The purpose of a check valve is to allow the water to flow through it up the discharge pipe, but prevent the water from flowing backwards below the check valve so the same water does not return to the sump pit over and over burning out the pump motor.
A gate or flapper. All check valves must have a gate or flapper that closes when the pump stops running. The gate or flapper allows water to pass up through it when the pump motor with the force created by the impeller pushes the water upwards through the discharge pipe.
The gate (flapper) closes when the water comes flowing backwards down the discharge pipe after the pump shuts off because there is no more pressure to push the water up. Gravity takes over and allows the water to run back down the pipe upon pump shut off.
Two end connectors. All check values have connectors at each end of the valve so they can be attached inline with the existing discharge piping.
Check valves are meant to be installed inline with the discharge piping system.
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True union couplings is a connection in which the check valve can be screwed and unscrewed easily for valve replacement. The union coupling has two ends. One end is screwed into the check valve body (this makes it easy to screw the check valve body out easily). The other end of the union coupling fits inside the PVC discharge piping system. The end that fits into the PVC pipe must be primed and cemented (the purple and clear liquids). An O-ring is seated inside the union that screws. This provides a very tight seal preventing leakage. The check-valve pictured on the right is known as a union x union coonection. The check-valve body is that of a quiet check valve.
Hose Clamp x Hose Clamp connector is a connection in which a rubber connector comes already slipped over both ends of the check-valve body.The other end of the rubber connector is sliped over the end of the discharge piping system. Clamps are screwed over the slip connections and tightened with a flat head screw driver to prevent water from dripping out. The slip x slip connector makes it easy to remove the check valve body for replacement. Over time it is possible the clamps will loosen and water will seep out. In that case, just take the screw driver and tighten the clamsps again. This type of connection requires no glusing.
Slip x Slip Connector type is one where both ends of the check valve slip over discharge piping system. The end that fits over the PVC pipe must be primed and cemented (the purple and clear liquids) to the discharge pipe. This eliminates the possibillity of water seeping through the connection; however the discharge pipe system must be cut when the check valve must be replaced. To install a new check valve may require an additional disharge piping piece and a connector or union to replace the length of PVC that was cut out.
FIPT x FIPT Connector type is not too commen. Both end of the check valve are threaded on the inside so can be connected to a threaded male PVC of the same size.
Cast Iron Cast iron is extremely durable. It will withstand the water pressure and not be affected by the chemicals found in the water. This type of check valve uses a flapper to stop the water when it flows backwards down the discharge pipe to the check valve.
Strong Plastic (PVC)Strong plastic can also withstand high water pressure and will not be affected by the chemicals found in the ground water. Both flappers and gates are used for this type of material.
Usage of clear plastic The usage of clear plastic for the walls of the check valve chamber make it easy for the homeowner to view its operation. A check-valve failure can be seen by watching how the gate opens and closes.
Usage of non opaque solid plastic or iron The usage of non opaque plastic and iron makes it impossible for the homeowner to view the chamber during operation. The homeowner will know the check-valve flapper or gate has failed when water runs down the discharge pipe after the pump has shut off and water is flowing backwards toward the check valve. The check valve will not hold the water above its gate or flapper.
A hydodynamic design inside the check valve chamber makes a difference. Such a design influences the degree of pressure loss and air entry. Likewise a tightly fit seal controls the amount of water and air pressure change. A design which controls the pressure change and allows the gate to close quickly reduces the likelihood of water hammer.
A flapper swing does not control the impact of the water pressure. It merely responds to the increase and decrese of pressure. Pit water gains pressure as the level of water rises in the pit, as the motor is running and as the pump impeller increases water flow velocity. The flapper opens when the pressure increases. When the pump motor shuts off, the water pressure and velocity greatly decrease and the force of gravity causes it to flow backwards and down the discharge pipe. The backward flow of the water pushes against the flapper and causes it to close.
A spring loaded gate uses a heavy-duty tension spring to take control over the effects of the pressure and velocity of water flow and keeps the pressure constant as much as possible. At a predemined degree of pressure, the tension spring allows the gate to open upward. Likewise the spring will close the gate when the water begins flowing backwards. The tension spring minimizes the change of the increasing and decreasing level of pressure to the extent that water hammer is not heard.
A flapper swing makes the most noise because the water pressure causes the flappers movement. The lose of water pressure and velocity when the pump shuts off causes the water to flow backward. As the water flows backward it hits the flapper, causes it to shut and causes a slamming or thudding sound.
A spring loaded gate is the quietest because the spring controls the movement of the gate. The tension of the spring keeps the pressure as constant as possible and responds in a controlled manner when the water pressure decreases as a result of the pump motor shutting off. The pressure change when the water flows back to the closed gate is less which causes very little sound.
Remove as much water from the sump pit as possible. Also remove small pebbles, sludge and debris as well. Small pebbles can get caught in the check valve chamber and cause it to fail.
Check the new check valve length with the old one. Obviously replacing the same check valve with a new one is easiest because the lengths will be the same.
Unplug the pump cord. Disconnect the lower end of the old check valve from the discharge pipe.
Release the water from the old check valve. Drain the water into a 5 gallon pail.
Remove the top part of the check valve from the discharge pipe.
Check if the bottom discharge pipe attached to the pump is too short or too long. If it is short, add another piece of PVC. If it is too long, measure where the pipe needs to be cut so the new check valve will fit in place.
Cut off the excess length of the bottom pipe where you measured with a hack saw.
If a slip x slip connections is used, steps 8 through 15 are not necessry. With a union connection, connect the nut of the union of the new check valve to the bottom pipe. Prime and glue it in place.
Do a dry run to see if remaining check valve piece fit between top and bottom of discharge pipe system.
Do a dry run to see if the check valve chamber fits in between the top and bottom of discharge pipe system.
Make sure the check valve chamber is placed in the right direction. Find the arrow on the check valve chamber. Make sure it points 'up' The gate should be placed so the water hits it from the top.
After doing a dry fitting, prime the piping and fittings.
Glue fittings one by one.
Hold fittings until they set.
Screw the check valve in place.
After hand tightening, use a wrench to tighten a little bit more so there a no leaks.
Plug the pump into an electrical outlet. Look for leaks. Check for unusual running water sounds or shootiing water when the pump shuts off. If none, your project is done.
Manufacturers recommend sump pump check valve placement be three feet (36 inches)above the sump pump. Many sump pump pits are around 24 inches (two feet) deep therefore the check valve would be placed 12 inches (one foot) above the sump pit cover or twelve inches above the basement floor.
Always check the Manufactures User Installation Guide for additional information regarding installation of the check valve height for your primary (main)sump pump.
A flapper swing designed check valve failure will show water dripping from the check valve downward into the pit when water is pumping through the discharge pipe.
By shaking a check valve you will be able to hear the failed flapper bouncing around. Here is a good example of what it sounds like.
The spring loaded check valve closes much quicker than the swing (flapper) style. The faster the valve closes the less noise because the velocity or pressure of the water coming back down the discharge pipe system toward the pit is less. The water pressure change and flow velocity affect the noise level.
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The Zoeller 30-0181 is a Number One Best Seller. Overall it has a rating of 4.7 out of 5. Of the 243 consumers reviews, 183 gave it a 5 star; 43 gave it a 4 star.
A summary of the reviews indicates the Flapper Swing style check valve works great, it is easy to install; it is well worth the cost.
One of the consumers, Victor Agresti, describes the mechanical workings of the check valve as the following. When the sump pump comes on, the valve flap swings completely out of the way, to allow maximum flow. When the pump stops, the flap closes to stop water from going toward the pump. He has also found another unique purpose for the check valve. A check valve prevents mice, insects, etc. that crawled in through your exit pipe, from making it all the way to your sump pump. When the water comes on, critters should be washed away.
The Zoeller 30-0181 has a full flow design. The flapper opens completely, unlike many cheaper valves. The connector for this is versatile. It is a 1 1/4 inch design with universal rubber couplings that connect it to either 1 1/4 inch or 1 1/2 inch PVC pipe. When it is installed you need to turn the rubber couplings one way or the other to accommodate the correct PVC pipe diameter for your application. The check valve does klunk with a loud snap but this doesn not bother me. The quality is good and it is a good choice for me.
The Zoeller 30-0181 check valve is easy to install. You only need a standard screwdriver for installation if you are replacing an old valve and maybe a hacksaw if you need to cut away some of the pvc pipe to allow for the proper fit.
There were arrows printed right on the valve to help me fit in the proper direction so it opens and closes in the correct direction. I am no plumber, but installing this was easy. I was surprised how easy it was.
The price on these is great, they are built very well. This was a great investment.
I bought the Zoeller check valve and have it installed for five plus years. It is working great so I am buying another one. One thing I have noticed is that with a rigid PVC piping the pump and discharge line move around a bit when the pump stops. My pump has plenty of room so the float will not get caught on the pit wall.
Every winter I have to remove the check valve because the discharge line freezes solid in the coldest Minnesota weather with our old, drafty house and its cold basement. Removing the check valve allows the discharge line to drain completely after each cycle.
In the spring I reattach the check valve and evertying is fine. The clamps and adapters included with this pump make the attachment and reattachment job a breeze. The connectors show no signs of wear from the regular changes. I have had it installed for 5 years now and it is still working fine.
This seems to be a much better engineered product than what I found on the shelf at my local hardware store. The cost is the same so I am glad I bought the Zoeller Check valve.
The check valve does exactly what it is supposed to do - keep water in the discharge hose from backing up into the sump pit. I am happy I bought it.
The Campbell Mfg. Spring Quiet Check Valve B-0823-15C is a Number One Best Seller. Overall it has a rating of 4.9 out of 5. Of the 304 consumers reviews, 285 gave it a 5 star; 10 gave it a 4 star.
A summary of the reviews indicates that consumers like the fact they can see the check valve work when the pump runs; the quiet check valve is easy to install; it works great; it is so quiet compared to the other kind; it is well worth the money.
One of the consumers,Roy, indicates he has tried check valve types over the years to eliminat the dreaded thud and none of them have worked very well. They were all designed the same way and obviously all had the same result....THUD. This check valve has a much better design. A design that I think should almost be mandatory!! It took just 15 minutes to install. You will need the plumbing cleaner & cement for the connectors.
I purchased the Campbell B-0823-15C Quiet check valve. I installed it for my primary pump. I liked it so well I bought one for my backup pump as well. It is really a great design bacause by having the threaded couplers it is easy to disconnect the pump or the check valve. What a big improvement over what I have before. I also like the fact that the chamber is transparent. I can see if there is any debris or sediment that needs to be cleaned out. My pumps and check valves are both quiet now. I check to see if the valve opens and closes because I cannot hear it running.
We had a clanging noise coming down our vertical pipe that is attached to the pump. I was not sure if we have a bad discharge pipe or what. Now that I have installed the Campbell Mfg 1.5 inch Quiet Check Valve B-0823-15C I know the sound came from our old check valve. The loud noise could be heard throughout the house. Now with this quiet check valve, I almost cannot even tell if the pump is running when I am next to it. What a brilliant design. I would recommend this to anyone.
The Campbell Quiet check valve really impressed me. When I picked the packaging box up the B-0823-15C was heavy. When I opened the box and saw it, I knew I had a quality product. This is extremely heavy duty. The clear plastic is quality. This product allows you to solvent weld (PVC glue) the check valve in place. When the unit needs to be replaced it will only take seconds to unscrew the o-ring unions on each side of the check valve and drop a new one in. This check valve is far superior to the rubber fernco type fitting on each end. I need to order another one because it is good to have such a good quality product on hand.
I am impressed. The Campbell Silent check valve is really quiet. I am amazed at how it works. The pressure in the chamber and the design of the spring gate prevent the flap from slamming shut. Before I bought this I had a cheap one that had flaps that could not hold the pressure weight of the water above it. The old valve flaps were flimsy and they broke downward through the hole, thus causing back flow when the back-up sump was operating.
The quiet check valve uses a very hard, sturdy plastic gate flap that does not look like water pressure can break it through the lower opening. I really like the look-through, transparent chamber because you can see whether the gate is functioning when you test it. I have been used to the slip x slip connectors so I replaced the plastic screw couplers with rubber connectors for about $2.50 each to connect the top end of the tube. So far the quiet valve has been through 5 years of heavy rainstorms and is working fine. So far so good.
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