Piston pump issue

[MatGyver]

Hey all, thanks in advance for any and all advice!
Here at my cottage in Ontario, we pull from a sand point with a piston pump into a tank which ends up just over half water to air and then up an approximately 15' vertical rise to the cottage system.
This system has worked for 30+ years with only minor find and fix issues.

The last few days I have had a new issue. In the am when I wake up there is nothing but air in the line...when I go to investigate and re prime which would be obvious, the prime is still holding right to the pump, but then nothing but air after that. Tank and system are empty?!‍♂️
I can't figure out where all that water is going...no obvious leaks, there is an acceptable amount of water on the floor(condensation, leather lube, etc).
I am able to disconnect the flex hose to the tank and back fill with water, reattach and plug in and BOOM, fixed!

I'm at a loss on this, so any ideas would be great!

 

[Reach4]

The softener backwashed overnight, and consumed all of the water from the tank? The piston pump sucked the sand point dry trying to refill the tank? Air could come from a vacuum leak or from the water at the sand point dropping and sucking some air at the sand point.

The float switch that controls the piston pump is intermittent, and did not start the pump, even tho the tank was empty?

Here at my cottage in Ontario, we pull from a sand point with a piston pump into a tank which ends up just over half water to air
Are you saying that the piston pump pumps a lot of air into the tank along with the water?

EDIT: I had mis-interpreted the post. I was thinking "a tank" was an atmospheric tank rather than the pressure tank.

 

[Sponsor]

 

[Valveman]

Yeah I don't understand why the pressure switch did not turn the pump back on after it leaked down? However, if it is draining down the pump suction, that is probably where the leak is.

 

[MatGyver]

No softener.

 

[MatGyver]

Also the pump was still running...just building air pressure in the system

 

[Valveman]

Also the pump was still running...just building air pressure in the system

Suction leak. Where was it getting the air?

 

[MatGyver]

Suction leak. Where was it getting the air?

These are the questions...full water from the point to pump...but air after...and I have no idea where that water is going?

 

[Reach4]

Try slathering the accessible joints with shaving foam. Include the connection to the pump. Make the pump run, and look for the foam being sucked in.

 

[MatGyver]

Here's my setup

 

[Valveman]

You have a high spot in the suction line before the pump. That is a good place for air to accumulate and cause a lose of prime. Also those hose clamps on the suction are a good place for an air leak. But again, the pressure switch should be turning the pump on at low pressure long before there is no pressure?

 

[MatGyver]

That is just a bad angle, it's almost dead level from point to pump. Also doesn't explain where the water is going from the entire system.

 

[Valveman]

Could be the check valve leaking back. But still doesn't explain why the pressure switch does not start the pump?

 

[MatGyver]

Could be the check valve leaking back. But still doesn't explain why the pressure switch does not start the pump?

Pump kicks on, but only pushes air. The point side is still full of water, tank side is all air!

 

[Valveman]

Maybe you have a seal out in the piston pump. Don't know much about them. But what about the pressure switch? Does it kick the pump on when the pressure gets to like 30?

 

[Fitter30]

Sure the sand point is still under water or a hole in the pipe? With tank full of air not some water has to be only sucking air.

 

[MatGyver]

Sure the sand point is still under water or a hole in the pipe? With tank full of air not some water has to be only sucking air.

Lots of water...it's still full at the point side of the pump. There has to be a seal in the pump that is stuck or something. My a rebuild. Working perfectly when it is though...just had a nice long shower!?

 

[Reach4]

Air must enter from somewhere. Maybe apply shaving foam to more seams.

 

[Fitter30]

When ever replacing a pumped seal i use either liquid soap or cooking grease like crisco on the rotating surface of the seal so when the pump first starts its not starting dry and washes right out. Rubber around the ceramic pushes in the casting easier and over the shaft.

 

[Bannerman]

I am suspicious of the section of reinforced vinyl tubing within the suction line between the check valve and the pump. It is apparent the tubing is collapsing at least partially when the pump is operating.

Vinyl over time tends to loose elasticity so with repeated flexing, the tubing can become more brittle and cracks may form which could be allowing air to be drawn in.

Alternately, the collapsing could cause the tubing to repeatedly rub over the edge of each barbed fitting, thereby potentially wearing a hole into the tubing.

Suggest replacing the section of tubing in the suction line with a section of pipe that will better stand-up to repeated negative pressure conditions.

 

[MatGyver]

I am suspicious of the section of reinforced vinyl tubing in the suction line between the check valve and the pump. It is apparent the tubing is collapsing at least partially when the pump is operating. Vinyl over time tends to loose flexibility so with repeated flexing, the tubing can become more brittle and cracks may form which could be allowing air to be drawn in. Alternately, the repeated collapsing could be causing the tubing to scrape

What do you recommend? I have always been told there should be flexible hose to and from the piston due to the vibration?!