Delay from when pressure switch clicks and pump turns on

[ballvalve]

He cannot have a delay unless air is getting into the system, it seems. So where is the air going? Its not bleeding out from a air release valve.

[LLigetfa]

Not true. The water column can fall in the pipe leaving a near vacuum in its stead. When the pump starts, it refills the pipe, hence the delay.

This is similar to a mercury barometer except that the water column weighs less so that the column needs to be more than 30 feet tall.

[valveman]

I’m with BV on this one. A vacuum in the pipe from a bad check valve would be like putting your thumb over a straw full of water. The water is under a vacuum but the water does not fall out the bottom. As a matter of fact the vacuum in a pipe fills up so fast when the pump starts, that water hits a second check valve and causes water hammer instantly. No delay.

I am thinking a bad check valve and a hole in the pipe at the top of the well. The bad check valve lets the pipe drain out when the pump is off because the hole up top lets air in. When the pump starts, the air goes out the hole while the pipe is refilling. This causes the delay in flow to the tank. Not a normal problem but, stranger things have happened.

[LLigetfa]

The water is under a vacuum but the water does not fall out the bottom.

I didn't suggest that it would fall out the bottom. I do know my laws of physics. With a bad checkvalve in the pump or a hole in the pipe near the pump, the water in the pipe will stay about 30 feet above the static water table. If the OP has a deep enough well and the static water table is low there can be a lot of pipe under vacuum. Simple laws of physics says it cannot fill instantly.

That's not to say that you cannot be right about both a hole and a bad checkvalve.

[valveman]

since it's 10 yr old along with the check valves.

I am sorry I haven’t mentioned this earlier, but you need to remove any check valves above ground. Without using water in the house, you will see that the pressure starts dropping the instant the pump shuts off. That will prove that water is going back down the hole, either because of a bad check valve or a hole in the pipe.

If this is happening, it needs to be fixed. Your pump is starting on up-thrust. Water running back down the well is stirring up the well. If your pump restarts before the water is through running backwards, it will break the pump or motor shaft. Not to mention the water hammer and the actual waiting for water problem you are having. But maybe the most important reason is that the place where the water is getting out maybe a break or unscrewing pipe coupling, which could mean you could soon be fishing for whatever falls in the well.

You can adjust the pressure switch and air charge in the tank to maintain supply to the house until the pump gets water to the top of the well. We do this a lot with soft start pumps. But with a regular pump, it is just a short term Band Aid that will leave you completely out of water at the most inopportune time.

[valveman]

If the OP has a deep enough well and the static water table is low there can be a lot of pipe under vacuum.

All the drop pipe will be under vacuum, from the upper check valve almost to the pump. But if there is no hole in the upper pipes to let air in, there will be no void or empty space in the pipe to refill. If the vacuum is strong enough, I guess you might pull a few air bubbles out of the water. This could make a small air space at the top, but it couldn’t be more than a cup or so. When even a 10 GPM pump comes on, it will pump a cup in a split second, the void will be refilled, and water will be flowing out the top of the well almost instantly.

Pumping 30 seconds at 10 GPM before water flows from the top of the well means there is a 5 gallon void. 5 gallons would probably fill the entire line of drop pipe. So I think the water is draining to the static level. I just don’t know where the air is getting out.

[LLigetfa]

All the drop pipe will be under vacuum, from the upper check valve almost to the pump. But if there is no hole in the upper pipes to let air in, there will be no void or empty space in the pipe to refill. If the vacuum is strong enough, I guess you might pull a few air bubbles out of the water.

Ummm... NO. the water column will fall to within about 30 feet from the static water table so if his water table is 130 feet below the topside checkvalve, the top 100 feet of pipe will have a vacuum and will not have water in it. When the pump comes on, it needs to fill that 100 feet of pipe.

It works just like a mercury barometer except that mercury is heavier so you don't need as tall of a column as you do with water.

[LLigetfa]

Pumping 30 seconds at 10 GPM before water flows from the top of the well means there is a 5 gallon void. 5 gallons would probably fill the entire line of drop pipe. So I think the water is draining to the static level. I just don’t know where the air is getting out.

We only know the depth the pump is at. We don't know the depth to the water table. We also don't know the size of the drop pipe. We can only assume 10 GPM.

Initially the OP said 10 seconds... later he said 30. Maybe all the upthrust on the impellers from the pump starting without any head exacted its toll on it already and it can no longer put out 10 GPM.

[valveman]

Ummm... NO. the water column will fall to within about 30 feet from the static water table so if his water table is 130 feet below the topside checkvalve, the top 100 feet of pipe will have a vacuum and will not have water in it. When the pump comes on, it needs to fill that 100 feet of pipe.

It works just like a mercury barometer except that mercury is heavier so you don't need as tall of a column as you do with water.

I guess I need a clear straw about 130’ long to see what you are talking about. I would bet that if the straw was full of water and I placed my thumb on top, the straw would still be full of water except for maybe the top 6” or so. But I don’t know how to figure that.

I have seen many wells holding vacuum from hundreds of feet deep. When you open a ball valve at the top of the well the vacuum is so strong it could suck your arm in easily. It can whistle so loud it hurts your ears. But I can also hear the pump running backwards and see the water level in the well rise. This makes me think the water did not fall out the bottom of the pipe until I opened the ball valve at the top. This is the same thing I see with a straw in my glass of tea.

I also know from experience that when you start a pump when the drop pipe is under vacuum, the water hammer thump hitting the above ground check valve happens within a second. Some of these wells had 3” or 4” drop pipe maybe 1,000’ feet deep. Even with a 100 GPM pump you would wait a long time for water to hit the surface the first time you turned on the pump. So long in fact that we use to keep putting our hand over the pipe while the air was being pushed out, just to make sure the pump was still running. But if you didn’t open a ball valve and let the air in, turning on the pump meant water would hit the above ground check valve almost instantly. With a good check valve up top and a bad one at the bottom, you have a very strong vacuum, but a very small void in the pipe to refill.

I would be curious to know how strong a vacuum it would take to make a 1 gallon size void?

[ballvalve]

I guess I need a clear straw about 130’ long to see what you are talking about. I would bet that if the straw was full of water and I placed my thumb on top, the straw would still be full of water except for maybe the top 6” or so. But I don’t know how to figure that.

The equation is heavily modified by the fact that maybe 100' of that straw is underwater.

The 130' straw with an open bottom will eventually drain by displacement of air up one side of the tube. I know, I make wine. The good barrel "wine thieves" all have a check valve on the bottom, with a point to touch the bottom of your glass with.

[LLigetfa]

I'm surprised that you professional pump men somehow think the laws of physics don't apply here. It is the very same law of physics that limit the lift of a shallow well pump.

The example I provided of the mercury barometer applies as well to water. The only difference is the weight. Whereas with mercury you only need a 30 inch tall column because it's so heavy, a column of water needs to be around 30 feet.

[Bobo]

We only know the depth the pump is at. We don't know the depth to the water table. We also don't know the size of the drop pipe. We can only assume 10 GPM.

Initially the OP said 10 seconds... later he said 30. Maybe all the upthrust on the impellers from the pump starting without any head exacted its toll on it already and it can no longer put out 10 GPM.

I timed it over the weekend with a stopwatch. It took 31 seconds from when the pressure switch cut in to when the pressure started to rise and 114 seconds for the pressure switch to cut out at 62 psi with an 80 gal tank. No water was being used from the time of cut in to cut out.

Correction: 31 seconds to pressure and 74 seconds to cut out. My stopwatch read 1 min 45 seconds total, I miscalculated using 145 seconds instead of 95 sec.

[Bobo]

Another slight problem is that in my infinite wisdom I built and really nice well house around the pump and tank and my landscaping doesn't lend itself to getting a truck back to it. I did construct the well house so it can be dismantled in parts. I have seen a few youtube videos of portable pullers. Is that a standard piece of equipment for repair companies nowadays?

LLigetfa

The vacuum in the pipe is interesting. Doesn't water evaporate in perfect vacuum? Interesting equation for figuring the time required to pump a vacuum aided waterhead of so many feet. To bad I don't know all the specs, might be able to determine if the pump is failing.

[Bobo]

The vacuum in the pipe is interesting. Doesn't water evaporate in perfect vacuum? Interesting equation for figuring the time required to pump a vacuum aided waterhead of so many feet. To bad I don't know all the specs, might be able to determine if the pump is failing.

Probably be better to calculate the time from cut in to cut out since that would be when the pump is operating in the proper context.

[Porky]

Since it looks like you may be updating everything you may want to consider adding a Cycle Stop Valve http://www.cyclestopvalves.com. It will stop the cycling and extend the life of everythinng plus give you constant pressure!