Stemmed vs Stemless Check Valve

[ACWxRADR]

I just mentioned check valves in another post as I had been shopping for a new one for a new well system.

Looking at all the different options, I was curious as to what the purpose and advantages were between using a stemmed, versus a stem-less valve would be. Does anyone have some comments to share on this?

Thanks

RADAR

 

[Reach4]

Here is a picture of a stemmed and stemless check valve from http://www.simmonsmfg.com/index.php/our-products/check-valves/ :

 

[Sponsor]

 

[ACWxRADR]

I do understand what the valves are and how they are constructed, but what is the manufacturer trying to accomplish with the different design? Is it for added flow (less restriction) around the valve? A better, more positive seal? Resistance to sand and grit? i.e. what is their sales pitch of one over the other?

I notice that a stem-less version is slightly more expensive, but not a great amount.

RADAR

 

[Valveman]

The stem in a check valve has to be a pretty tight fit. So if you have any sand or sediment the stem can lock the valve in the open or closed position. Also find that check valves with stems has a tendency to spin when installed on the discharge of a pump where the water is spinning. The spinning will wear the stem out quickly. Stem-less check valves will also spin, but they don't have a stem to wear out.

Flomatic makes a good check valve. But I would bet it is just a copy of someone else's, just like everything else they do.

 

[ACWxRADR]

OK, I can see this.

I did see a valve design while I was looking around that showed the spring for the poppet with a "tail" leg that was designed to insert into a hole in the body casting to prevent the poppet from spinning.

Around here (at our so-called resort) where everyone has a shallow well system, I have never known of a check valve of either style to "break" or wear out from just normal use. It was always that they failed due to damage from some other means. The person didn't winterize their system or didn't do so soon enough and the valve froze and broke. Or the well screen failed and the sand they pulled in wore out the seat or caught in the stem or there was just so much sand that it wouldn't seal. Or else it was a new valve that was simply a product defect right from the store.

RADAR

 

[ACWxRADR]

Reach,

I noticed that the images you loaded were from Simmons Mfg. That is the brand that I was planning to purchase. I d not trust the Water Source brand from Menards. Had a negative experience with one and heard from a well driller that they were known for failures.

RADAR

 

[Reach4]

I do understand what the valves are and how they are constructed

I didn't know about these, so after finding out what stemless/stemmed check valves were, I thought that others might want to see.

 

[ACWxRADR]

Reach,

Thanks for posting the pix! They showed up better than what I was looking at on the Simmons site. Makes a great visual presentation for the discussion, too. You can see really well the differences in the internals.

RADAR

 

[ACWxRADR]

Going further down the pipe, I am also looking at what brand and style of a driven well point to purchase. I have three brand choices that I am interested in, Merrill, Simmons and Johnson.

I sure would like to get the Johnson 1-1/4", SS V-wire drive point. But, these are roughly $100 more than any other top-of-the-line brand well points (about $280). I am not sure it is worth that much $ to me. Last well point I bought cost me about $50. My uncle has had an off-the-shelf hardware store brand in his well since the early 70's and it is still going. Probably cost him $15-$25 at that time. Because of our location near Omaha, NE , I'd bet it probably was a Merrill Mfg. brand. They are located in Storm Lake, IA. I think I can buy Merrill drive points locally for about $80.

However, I really like the Johnson V-Wire design as opposed to the standard slot or hole style. I believe it would produce more water and be less demanding on the pump, but not sure if it isn't a major overkill.

RADAR

 

[Ballvalve]

Going further down the pipe, I am also looking at what brand and style of a driven well point to purchase. I have three brand choices that I am interested in, Merrill, Simmons and Johnson.

I sure would like to get the Johnson 1-1/4", SS V-wire drive point. But, these are roughly $100 more than any other top-of-the-line brand well points (about $280). I am not sure it is worth that much $ to me. Last well point I bought cost me about $50. My uncle has had an off-the-shelf hardware store brand in his well since the early 70's and it is still going. Probably cost him $15-$25 at that time. Because of our location near Omaha, NE , I'd bet it probably was a Merrill Mfg. brand. They are located in Storm Lake, IA. I think I can buy Merrill drive points locally for about $80.

However, I really like the Johnson V-Wire design as opposed to the standard slot or hole style. I believe it would produce more water and be less demanding on the pump, but not sure if it isn't a major overkill.

RADAR

Johnson V- wire design is used in all water intake situations where absolute reliability is needed and self cleaning is possible, such as hydro power intake schemes. Definitely worth the money. Holes in a screen are obsolete.

 

[Ballvalve]

I would never put anything in a well that may last 30 years that has a 'O' ring inside of it. Any modicum of common sense will tell you that it will be prone to failure - the weakest link in your system. Look at a good check valve on a Submersible pump - carbide disk , on a lapped seat. NO spring, just a rod retainer. Rotates and cleans/laps itself. Use ball cone or ball check valves. Most ball check valves are low pressure, but the ball cones are fast sealing and have the lowest head loss [turbulence], and the least amount of internal parts to break and bung up the system.

The reason why those windmill pump cylinders last so long is that they use the simplest of ball checks to seal on the seat.

http://www.supplyhouse.com/Apollo-Valves-6110501-1-Threaded-Bronze-Spring-Check-Valve

 

[Ballvalve]

This Dempster pump had one?

Many do. Maybe that's why that one got pulled?

 

[Valveman]

The only time a check valve does any work is when the pump shuts off. So if the pump cycles 100 or 300 times per day, the check valve has to work 100 or 300 times per day. With the old pressure tank only method, when the pump is on it is always producing maximum flow. So the check valve is wide open when the pump shuts off. When the pump shuts off the water reverses direction and the check valve slams shut from the wide open position. When the check valve slams shut, it causes water hammer that can create 5 to 10 times more pressure than the max pressure the pump can build. So with a pump that is working at 100 PSI from the bottom of the well, the check valve takes at least a 500 PSI hit every time the pump shuts off. And when cycling 100 times per day, the check valve takes a 500 PSI hit 36,500 times per year. When the pump is cycling 300 times per day, the check valve takes a 500 PSI hit 109,500 times per year. As with my favorite quote from the movie Shaw Shank Redemption, "time and pressure can destroy anything". 500 PSI is a lot of pressure. And 100,000 times a year is a lot of times. This is what makes most check valves fail.

If the pump only cycles 20 times per day, like when using a CSV, the check valve only has to work 20 times per day instead of 300 times per day. Also when using a CSV the pump is only producing 1 GPM at the time the pump shuts off, so the check valve is only open the thickness of a piece of paper. A CSV reduces the number of cycles tremendously. And the CSV causes the check valve to close from a barely open position, completely eliminating the "hit". The CSV creates a "soft stop" that eliminates slamming check valves and the water hammer that accompanies said slamming check valve. The CSV can also create a soft start, which eliminates check valves flying wide open on pump start. Without a soft start, the check valve poppet gets slammed against the stop point with every pump start, which can also cause check valve failures.

Check valves, as with every other component in a pump system normally fail from excessive cycling on and off, as well as hard starts and stops. Reduce or eliminate pump cycling and the check valve and all components in a pump system will last much longer.

 

[ACWxRADR]

Valveman,

That is an excellent write-up. It makes very good sense and I had the exact contemplations in my own mind.

I have several advantages with my system that reduce those physical stressors on the check valve.

In my personal application, the well supplies a resort cabin. Therefore the usage is much less than a residential home. I am not there everyday using the well. The well is a shallow well with a sand-point and a pressure tank, so when the pump shuts off, the water isn't subject to the extreme reverse flow as in a cased submersible well that is 100 feet or deeper. The water in my shallow well has some added resistance when it returns to the static ground water table which is typically 10 feet deep. It also has to bleed back out through the substrate (sand and gravel bed) as well as through the sand point screen, which adds a measure of passive resistance. The water isn't essentially free falling back down the pipe string 50 or 100 or more feet with no restrictions. That would be a lot of force just considering the weight of the water alone.

There are 65 to 70 cabins here with the same setup, so this is probably why I have never heard of a check valve failing under normal usage and pump operation.

Regardless of the advantages of my well system related to check valve life, the information and explanation of damage (or wear) is greatly appreciated. This is good information to know. Generally, most people wouldn't pay much attention to the work that a check valve has to do.

It also helps to explain the trouble I experienced with the check valve I installed on my sister's water system. Even though I am certain that the new valve was poorly manufactured, it makes sense that the forces present when the pump shut off hammered the poppet down into the seat and caused it to stick.

For an above ground pump, I can also foresee that this could be a highly potential problem if the sand point (well screen) was plugged or on its way to becoming occluded. A person should address the condition of the well screen right away rather than trying to start and stop the pump over and over again. The suction created by a restricted well screen below the check valve would really hammer on the poppet and seat when the above ground pump stopped running. There would be pressure applied to the top of the check valve from the pressure tank above and suction below from the plugged screen. When the pump shuts off and stops pulling water, the check valve closes, WHAM!

RADAR

 

[Valveman]

Valveman,
The well is a shallow well with a sand-point and a pressure tank, so when the pump shuts off, the water isn't subject to the extreme reverse flow as in a cased submersible well that is 100 feet or deeper.
RADAR

If you are using a 40/60 pressure switch, the check valve is getting slammed with 60 PSI, which is the same as a check valve set in a well that is 138' deep. A 30/50 pressure switch would cause the check valve to see 50 PSI, which is the same as 115' down the well. This is not as much pressure as a submersible, but is enough to cause check valve failures if the pump cycles repetitively.

Resorts don't use any water a lot of the time when the place is empty. But on holidays and weekends the pump can be very busy and cycle a lot.
Thanks
Cary

 

[ACWxRADR]

I will add a disclaimer... The 60 Hz HUM is much different than relay "chatter" . Relay chatter is due to a loss and reacquisition of power to the relay coil. This is a different problem altogether and indicates something that should be addressed. 60 Hz hum is just an annoying problem, not always indicative any problem or defect.

RADAR

 

[ACWxRADR]

I dunno. I am too new at this forum to know the format for loading videos or pix here.

Gordy

 

[ACWxRADR]

If you can alter the format to match the site or link them up elsewhere, let me know.

\Gordy

 

[ACWxRADR]

Thanks!

 

[ACWxRADR]

Oh, you can call me doc. Np

ROFLMAO!

That is GREAT! I love your plates!

Gordy