Pressure Tank issues

[Paul Martin]

I recently replaced my pressure switch and tank. The pressure switch is set at 40 to 60 for cut in and out. I put 38 psi in the new tank. My pump is in the well.
Here is my problem. My tank is not filling up the pump runs for a min or so it builds up the pressure to 60 then as soon as it shuts off it starts dropping. Within a min it’s down to 40 and cutting on again. Even when I shut the valve going to the house it does the same thing. I’m guessing I have a bad check valve. But shouldn’t the tank be filling up?
Please help thanks

 

[Boycedrilling]

Yes. You have a bad check valve or a leaky pipe.

I had a service call this morning that that was the problem. It was at an onion packing facility. 40 employees. Told them we’re were shutting the water off at 9 am. 45 minutes to pull it, replace the check valve and reinstall it.

Unfortunately for me, I did it for free, under warranty. I had installed a new motor and check valve this summer. The check valve had failed after three years and took out the thrust bearing in the motor. I’ll be taking both of these 2” flomatic check valves back to the distributor, after the second one failed in six months.

 

[Sponsor]

 

[Valveman]

Hey Boyce, you know my answer to almost any pump system problem LOL. A packing plant with 40 people and a 2" line sounds like a potential for a lot of cycling. Those plastic poppets in most check valves just can't take the slamming from all those cycles. Eliminating most of the cycling and causing a soft stop at a low flow rate, a CSV will usually make even cheap check valves last longer.

 

[Paul Martin]

Will a bad check valve cause my tank to not fill up?
The tank is brand new gonna check the pressure in it I know if it’s to high it will cause it to not fill up. I’m pretty sure it’s not though.

 

[LLigetfa]

Will a bad check valve cause my tank to not fill up?

No. The pump will run until it reaches the cutout pressure at which the tank has the volume of water it is designed to have. What does "fill up" mean to you? Pressure tanks are never filled up. There is always air in the tank.

That said, if the system is plumbed badly, there is a chance the pressure switch will reach the cutout and the pressure in the tank will be lower than the cutout.

 

[Paul Martin]

The house is only 11 years old I’ve had it for 8 of them this is the first problem I’ve had with it. The old tank was very heavy when it filled up but I think the bladder was bad so I’m guessing it had filled both sides. The reason I don’t think it’s filling is because as soon as the pump is done running I pick up on the tank and it’s not very heavy. It’s a 20 gallon tank so I would think it would have some weight to it when it’s reached pressure. Should I add an a check valve or replace the one that’s gone bad. I’m guessing it’s in the well.

 

[LLigetfa]

First off, make sure your air pressure gauge and the water pressure gauge are both reading the same. It is a common mistake to assume they are when they are not.

Of course a waterlogged tank will be quite heavy compared to one that is not.

Adding a check valve at the tank is usually a bad idea. It can cause contaminated surface water to be sucked into the well. Also, it can create water hammer which in turn will cause more problems.

You need to determine where the water is leaking back. Pulling the pump up a few feet if you have a pitless may be required to test the system. If you have a spare identical pitless simplifies testing as it can be used to split and cap the system in two. Installing a temporary check valve just before the pitless is another way to test or use as a temporary mitigation until you can pull the pump.

 

[Paul Martin]

I’m not sure what a pit less is but I know I only have the one well.
Is it hard to pull the pump?
Is there a way I can tell if I have a leak without digging up the pipes running from the tank to the well?

 

[Valveman]

Even when "full" a diaphragm tank should feel empty. A 20 gallon tank only holds 5 gallons (40#) of water, and that is right in the bottom. The tank should feel and sound empty. The connection to the pipe should give more resistance than the weight in the tank. If it is heavy and sounds full, it is a bad tank.

You said "when the pump is done running". That makes me think it is reaching 60 PSI, the tank is full, and the pump shuts off. Then if the pressure starts dropping immediately even though no one is using water, there is a leak somewhere. If you have a ball valve on the line going into the house shut off and the pressure stops leaking down, the leak is in the house. If the pressure still drops with the ball valve to the house closed, the leak is down the well or in the yard. It could be a leak in the pipe or a bad check valve on the pump. A leak in the underground pipe will sometimes cause dirt in the water. A leak in the drop pipe in the well will usually cause air to blow a glass out of your hand at the sink. A bad check valve at the pump is most likely the problem, since you haven't said anything about air in the lines.

Then as usual, the reason the check valve in the pump failed was from the pump cycling on and off too much. This slams the check valve shut with each pump stop, and throws it wide open against the stop on pump start. In other words, when you get the check valve replaced, a Cycle Stop Valve will keep this from happening again, while adding several other benefits.

 

[Paul Martin]

I will replace the check valve. Im hoping it’s not a leak in the piping.
Thank you for all of your help.