No water pressure.

[findingzzero]

I noticed a slight drop in water pressure about 2 mos ago, Today? No water. Goundfos system, CU 301. The pressure valve on the tank shows 80. I drained the tank to 0, then refilled, and the pressure went back to 80
and I have water for the moment. The air pressure in the tank is also 80. It goes up with the water pressure. I know enuff to be dangerous. I was thinking it was a tank issue. The pump is set at 70 and is not running continuously. I think she's gonna blow, Dano!!
Help before the plumber comes tomorrow..

 

[John Gayewski]

Sounds like a clogged pipe somewhere. Something needs cleaned.

 

[Sponsor]

 

[Reach4]

Clogged filter or closed valve would be my suspects.

 

[Valveman]

You are not suppose to ask questions, just order a new CU301 and maybe a pressure tank. That is what those things are designed for. Lol. I would get a 40/60 switch from the store and replace the Transducer, also removing the CU301 completely. You can tighten the large adjustment screw in the 40/60 switch about 7 full turns to the right and turn it into a 60/80 pressure switch. Then if the pump is still working fine, I would add a CSV1A before the pressure tank to do the constant pressure thing and keep the pump from cycling on and off.

Most likely the tank diaphragm is bad because the CU301 hasn't been working for some time. When that happens the controller just starts cycling the pump on and off like a regular pressure switch. The cycling wore out the diaphragm in the tank and will also damage the pump.

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[findingzzero]

Can I just replace the tank?

 

[Valveman]

Can I just replace the tank?

The tank is most likely bad, but it was destroyed because the CU301 has failed. See if any water comes out the Schrader valve on the tank and you will know it is bad.

You can replace the CU301 and transducer with a regular pressure switch. But you will then either need a big pressure tank or a CSV and another small tank.

 

[findingzzero]

I didn't notice any water coming out of the schrader.
It seems to be working now. Is that just temporary? What is that gauge measuring, water pressure? I got the same reading at the schrader valve.

 

[Bannerman]

I got the same reading at the schrader valve.

It seems you are checking the air pressure while the tank's water chamber continues to contain water. When there is water in the water chamber, the air and water pressures shouid be equal.

The tank's air pre-charge pressure, is to be tested with the pump's power supply shut off, and after the tank's water chamber is completely drained of water.

didn't notice any water coming out of the schrader.

The Schrader valve is typically located on the very top dome of the tank. For water to exit from the Schrader valve during a brief check, would normally require the air chamber to be completely filled with water. Since any air remaining within the air chamber will be located at the top above any water, you would need to release all of the air through the Schrader valve while the pump is running, to cause water within the air chamber, to be pushed out through the Schrader valve.

Once you shut off the pump and then drain as much water as possible out from the tank, usually gently rocking the tank side-to-side, will provide an effective method to determine if the tank actually contains 0 water, or whether there is some water trapped within the upper air chamber, above the diagram. Water within the air chamber indicates the diaphragm is damaged, thereby requiring replacement of the tank.

 

[Reach4]

I didn't notice any water coming out of the schrader.
It seems to be working now. Is that just temporary? What is that gauge measuring, water pressure? I got the same reading at the schrader valve.

With the Schrader valve on the bottom, lack of water coming out of the Schrader valve is meaningful. If the Schrader valve were on the top, then it would not be informative.

Make sure you set the air precharge for that system according to the manual. You don't use the same air precharge pressure that you would use for a conventional system.

Air precharge is always measured and set with the water pressure zero. If the water pressure is higher than the precharge, then the air and water pressures will be nearly the same. That can be useful to see if the gauges are in calibration with each other. There can be small differences (probably less than 1 PSI), with your bottom-mounted Schrader valve air pressure to read a little higher than the gauge above. The two factors leading to this is the difference in altitude, and the diaphragm not being perfectly limp.

 

[Valveman]

With the Schrader on the bottom, if the tank is bad water will come out as soon as you push in the valve core.

If the problem is intermittent, it may be tripping the overload in the motor.

 

[findingzzero]

Spoke to the well Co. Nice old guy. Younger than me. He told me about draining the tank b4 measuring the pressure. Emptied the tank. Set the pressure at 48. Filled the tank with water to about 70. This kind of pump is soft on/off on demand. Not sure why then it needs a small pressure tank. Let's see how this goes. Thanks all.

 

[Valveman]

Glad you got it working. But we know how it will go. About the third time you replace that $800 CU301 box you will figure out how pump systems should be controlled.

There are really only two ways to control a pump. One makes the installer happy. The other makes the customer happy.