Do I need a pressure tank?

[Stephenson]

Hi All,

Back at the lake and have a pump/pressure tank question.

My 3/4 HP StaRite SND-L pump (about two years old - the last one cracked after some idiot didn't properly drain it for the winter)(me) is about 12' above the lake level with another five feet under water to the suction point.

It feeds the dock hose bin, and two other bibs (75' away and 500' away, respectively. It is still connected to an unused irrigation system.

The horizontally mounted pressure tank has failed .... preamble to a short question: do I need a pressure tank at all in my circumstances?

Thanks.

 

[Valveman]

Yes. The bladder in the tank failed because the pump was already cycling on and off too much. So you either need a larger tank, or a Cycle Stop Valve and a new small tank.

 

[Sponsor]

 

[Stephenson]

Stand by ...more investigating turned up what I think was a cracked T below a post supporting one of the hose bibs ....was checking and when I moved the post about an inch it snapped ...since that material is pretty tough, I think it was already cracked ...

Am gonna eliminate this bin since we don't use it anyway ..,.let you know!

 

[Stephenson]

Update ...

Removed the T that supported the hose bib, replaced a piece of the 1 1/4" pipe ...no leaks.

Ran pump, again ....still bleeding down without water turned on anywhere.

Numbers:
- 22 seconds to drop from 50 to the 30 psi switch on without water line open anywhere, then 3 seconds to go from 30 to 50 psi cutoff
- 5 seconds to drop from 50 to 30 with the closest faucet turned on

Can this be caused by the pressure tank? It us a Flotec 7100-09 mounted horizontally ...see photo. Likely original to the dock ...maybe 15 years old.

 

[Valveman]

The tank has nothing to do with it. If the pressure is bleeding down when no faucets are open, water is going somewhere. I am guessing a bad foot valve.

 

[Stephenson]

Valveman, thanks!!

So, if thinking correctly, the pump pressurizes the line including against the pressure tank ...then, when it stops running, the pressure tank assists gravity in pushing the water back through the pump into the suction side of the system back through the open foot valve?

In my past examination swims, I've noted where it is ...about six feet below the waterline and about three feet above the bottom ...the line is attached to the dock near the waterline (I suppose so is accessible?) ...there is also a capped off T just below the waterline (which at time is above the water) ...I remove the cap to winterize and drain line.

I looks like some of these can be cleaned?

 

[Valveman]

Yeah you are thinking correctly. And every time the pump shuts off "gravity" and pressure slams the check/foot valve closed. When a pump is continually cycling on and off, the check valve gets slammed until it no longer shuts as it should. Probably going to need a new foot/check valve.

 

[Stephenson]

Went swimming ...

PVC check/foot valve ...not very dirty - cleaned before pictures but just light junk.

The filter end came off easy with little pressure ...maybe even loose, which based on valve design would not completely seat and tension the valve.

Further, the male threaded connector, which looks to be a universal "cut at the diameter you want" was very poorly cut - not square! Don't know if this would affect seal - lots of tape on the threads so maybe not so much?

Going to look for new assembky and valve.

 

[Valveman]

Get a metal valve. Plastic check valves can't handle as much slamming from cycling as metal spring loaded check valves.

 

[Stephenson]

Just back ...no metal in stock at local place ..,.here's side by side photo of old and new.

New one has a but diff design ..

Old one rattles a lot when it fully assembled...new one doesn't ...

 

[Stephenson]

Swimming, again

Installed and connected and secured.

Cranked up pump and primed ....still had drop I could see ...found a little leak at the winter drain T ...installer orig used cast iron nipple and had pvc cap on that. Rusty ...lots of pipe tape and think have sealed.

I carefully watched:
- takes a lot longer to drop from cutoff with valve open
- takes a minute or so to drop to 45 then several minutes to drop to 40
- it does drop, though ...storm swept through so I left it on ...will see later

I do have 500 ft of 1 1/4" line going uphill ...it connects somewehere to the old irrigation valves ...will have to look for water ....not much can be leaking though ...

 

[Reach4]

I do have 500 ft of 1 1/4" line going uphill ...it connects somewehere to the old irrigation valves ...will have to look for water ....not much can be leaking though ...

You probably have a valve between the pump and the pipe going uphill. Try closing that valve to see how that affects the pressure loss.

 

[Stephenson]

No shutoffs that I can find ...three bibs on the line including the one on the dock...furthest bib has good pressure.

 

[Stephenson]

OK ...just checked on it.

Now worse than earlier ....30-40 seconds from 50 down to 30 psi ....

I don't see any water, I don't hear any water running through the line where I removed the bib ...I don't get it ...

Thoughts?

 

[Valveman]

That small pressure tank only holds about 1 gallon of water. So if you are losing from 50 to 30 in 30-40 seconds, you have about 2 GPM leaking somewhere.

 

[Stephenson]

Hi again...

Thanks ...any tips for finding leak? Leave pump running for few hours and look and listen? Will this harm pump coming in and going off?

 

[Reach4]

No shutoffs that I can find ...three bibs on the line including the one on the dock...furthest bib has good pressure.

If you added such a valve, it could tell you which side of the new valve the leak is on.

 

[Stephenson]

Latest ...

Spent an hour walking an acre foot by foot looking for wet spot ...found one ...dug an increasingly large hole ...irrigation zone valve that sits on top of the 1 1/4 main line.

PITA to sit around the wiring ...

Found crack in the male thread that connects to the female 1 1-4"-1" T ...

 

[Stephenson]

Valveman ,

Ya kept me going the right way ...new fittings and a splice to make connecting the 1" pipe to the bathroom bed 90 work ....

Not sure if there is much strength diff between the gray material threaded 90 I took off and the schedule 40 pvc I put on ...only one the store had anyway.

Watching gauge ....pretty steady at 50 ...open dock hose and can run for about a minute before drops to 30 psi.

Have three other unused irrigation zones ...fingers crossed!!

Thank you, again.

 

[Stephenson]

Stable at about 15 minutes between pressure drop cycles ...what does this mean?