Author Topic: Wild pump-side pressure swings at startup  (Read 280 times)

joea

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Wild pump-side pressure swings at startup
« on: December 12, 2022, 05:04:16 PM »
Hi, I’ve had a CSV1A system for over 5 years with seemingly no problem. This summer I found the pump short-cycling and found I needed to replace the gutpack. Since doing so I’ve been having intermittent problems. On 3 separate occasions I lost all water pressure about 5 minutes into a shower (2 shower heads going, probably about 5gpm). The water pressure comes back perhaps a minute or so after shutting it off. I’ve been trying to diagnose what’s going on, and I’ve found that pump side water pressure and also motor amp draw can swing wildly at startup. I don’t know if this is related to my problem or not but would appreciate any insights. Here are details of my setup, followed by more info on my observations.

500ft well, static level 90ft, yield 3gpm.
1HP Goulds pump (model M10422) placed at 480'. Don't have info on water-end but crudely measured about 12gpm.
WellXtrol WX103 7.6g tank, about a 2gal draw-down (verified by measuring it), precharge at 48psi
50 - 70 psi switch
CSV1A adjusted to 55psi
Normally see about 140psi pump-side when CSV sets at 55psi

I’m finding erratic operation at pump startup. I’ve run tests turning on the 2 showerheads. Following pump turn-on I see the pump-side pressure wildly swing between about 50psi and 140psi and the motor current swing between 10A and 20A. The tank side pressure holds steady slightly over 50psi, but below the 55psi setpoint. Eventually it settles with pump-side at 140psi and tank-side at 55psi and power draw about 11A. The amount of time these swings last before settling varies wildly. In one case it went on for 30 sec, in others it can settle very quickly. In the 30sec swing startup case I continued running the shower for about 20 minutes. Everything held rather steady although tank-side pressure very slowly dropped to about 50psi (I assume because of well water draw-down).

I don’t recall these startup swings occurring in the past and can’t really imagine it’s related to the gutpack replacement unless perhaps I have problems with the adjustment. I also don’t know if it’s at all related to the times I lost all water pressure, unless it’s perhaps indicative of some intermittent pump problem. I don’t believe it’s a problem with water level in the well. I’m in the NC mountains and this has been an extremely wet year and the last several years have been above normal. Never had problems with water even in dry years.

Any suggestions on how to diagnose would be greatly appreciated. I’m getting ready to call in the pros, but I’m concerned the first thing they’ll say is get rid of the CSV and after that they’ll shrug their shoulders because the problems are intermittent and may not present itself when they’re here.

Cary Austin

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Re: Wild pump-side pressure swings at startup
« Reply #1 on: December 13, 2022, 07:45:15 AM »
Sorry for your problem.  Unfortunately when a pump goes off like that then comes back on by itself in a minute or so the overload is tripping.  Sub motors have an auto-resetting overload.  After the motor cools for a minute or so, the pump or water seem to just magically come back on.  If you have a 3 wire motor with a control box the start cap and relay need replacing.  If it is a 2 wire motor with no control, there is nothing you can do.  Anything over 10 amps is going to trip the overload. 

This kind of damage is caused by cycling.  The CSV NOT working for a while was the problem.  Just don't let the installer remove the CSV as that is what will keep the motor from failing again.

joea

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Re: Wild pump-side pressure swings at startup
« Reply #2 on: December 13, 2022, 08:31:07 AM »
Ok, thanks for that info. Prior to originally putting in the CSV I had a water-logged tank and the pump was short cycling for who knows how long before I discovered it. Likewise I don't know how long the CSV guts were worn out before I replaced it. I've learned my lesson and have now put in place monitoring for short cycling (using home automation devices).

The motor is 2 wire. The overload tripping explains the complete water cut-off. What causes the startup pressure and current draw swings? Is that because of existing damage to the pump? Are there any adjustments I can make to reduce this (e.g. higher/lower CSV setpoint)? What's your view as to the status of the pump. Am I likely heading for a complete failure in a year or two and therefore may as well bite the bullet and replace it now?

Cary Austin

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Re: Wild pump-side pressure swings at startup
« Reply #3 on: December 13, 2022, 10:13:00 AM »
Short cycling causes carbon to wear off the thrust bearing.  The black crud gums up the motor and makes it sticky. That and the wear on the thrust bearing make it hard to start.  Don't know that you have much choice as it will most likely just not start again.  But sometimes it surprises me how long they will limp along.

joea

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Re: Wild pump-side pressure swings at startup
« Reply #4 on: December 13, 2022, 05:23:06 PM »
Ok, new pump it is. Knew it my heart, but had to ask. I'll let the boys enjoy their holiday break and then give em a call in Jan. I think I'll also upgrade the pressure tank from 7gal to 20gal. It'll give more safety margin and hopefully limit the debate I anticipate with the pump folks over the CSV.

One more question if you'll entertain it. I've always had a sediment problem with the well and have a spin down filter followed by a whole house filter placed after the tank. The spin down was previously a Rusco with a 140micron mesh. It would need to be flushed every week or so and taken out and cleaned every month or so. I've recently replaced that with an iSpring wsp50j. This has a 50micron screen but it has a significantly larger filter area. I also automated the flush such that it's done based on pump operating time and is done rather frequently. Seems to work well so far. I'm thinking about placing that between the CSV and the pressure tank (keeping the whole house filter after the tank). I see there's a lot of debate as to whether sediment can ruin a tank, but I can't get it out of my head that it did contribute to the early demise of my original tank. I also really like the idea of the spin down being ahead of the tank because a flush will actually bring water back through the mesh screen and force crud out of it rather than just flush around the outer mesh. Should be much more effective, at least theoretically. I've seen posts about the concern of a clogged filter preventing enough water flow to fill the tank and shut off the pump, but I think the large mesh area and auto-flush should minimize the likelihood of that. Then again, while replacing a tank isn't cheap it's much less painful than replacing a pump. Would appreciate your view and in particular is there anything I'm overlooking as I debate myself. Seemingly good ideas in the past have gotten me where I am today - in need of a new pump....

Cary Austin

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Re: Wild pump-side pressure swings at startup
« Reply #5 on: December 14, 2022, 07:11:57 AM »
A 20 gallon tank is fine, but nothing wrong with the 7 gallon tank.  Those pump guys would not think twice about using a 7 gallon tank with a VFD, and that is much harder on the pump than a CSV.  If you don't educate the pump guy he will remain clueless because his suppliers want him to keep selling those very profitable VFD's, so they are not going to say anything good about the CSV.

You can put a filter prior to the CSV but it will see max pump pressure instead of just 40 to 60 PSI.  If the filter is rated for the pressure it will work fine.  However, sounds like you need to develop the well.  Just leave the filter off and run a large pipe of water for hours or days if needed to clean the crud out of the well.  If you clean the well properly you won't need the filter for much.

It takes a large amount sediment to destroy a tank.  The way a diaphragm tank works everything that goes in, comes right back out.  But that diaphragm going up and down with each pump cycle is what finally tears a hole in the diaphragm.

joea

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Re: Wild pump-side pressure swings at startup
« Reply #6 on: December 14, 2022, 10:03:23 PM »
So I don't need a 20 gal tank, that's interesting. Let's see, I replaced the CSV1a valve back in July, and back then I had a 45sec tank fill time using a tank almost twice the size of your recommended configuration. That is by the way about the same fill time I had with the original valve and back then I was told it was fine. Now, 6 months later, the tank fill time is 30sec. What's it going to be in another 6 months? So I need to get a new pump, I don't need a larger tank, but then I follow with what? A new valve every 6months? Every 3 months? Or every week???

Cary Austin

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Re: Wild pump-side pressure swings at startup
« Reply #7 on: December 15, 2022, 08:08:46 AM »
A CSV1A should last 20-30 years.  It would take a LOT of sand or something to make the CSV1A fail in a short period of time.  As long as the CSV is working it is what keeps the pump from cycling, so a small tank is all that is needed.  If you don't have a CSV or the CSV is not working you can't get a large enough tank to eliminate the cycling.  The low amps caused by the CSV is why it is not important to have 60 seconds of rum time to fill the tank.  Without a CSV 1 minute of run time is not enough, 2 minutes is better, and running continuously is best.

The CSV1A is in warranty if is fails.  Send it to me and I will inspect it to see why or if it failed.

joea

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Re: Wild pump-side pressure swings at startup
« Reply #8 on: December 15, 2022, 08:07:44 PM »
A warranty on the valve does me no good, I need a new pump and for that matter a whole new tank setup. I don't know how long it was before I realized the first valve went bad, but seeing how fast this new one is chewing itself up it's fair to say my pump had been short cycling a long time. And no, there's not nearly that much sand. The problem seems rather obvious, I have a deep well application and the high differential pressure on valve is ripping it apart. Before my pump was compromised I had a 130-140 psi differential, but at the outset I was told that was fine. You repeatedly claim that in all your years there has never been a pump failure from a "properly" installed valve, but then throughout this forum you constantly advise people how to improperly install your product. In post after post after post you tell potential customers well yes the spec says a max differential pressure of 125 psi but you're fine at 150psi, well yes the valve will produce a 200psi back pressure against your pipe rated for 160psi but that will be fine, well yes we'd like to see a minimum of 1min run time but with my valve 30sec will be fine, and on and on and on. Well yes, they're probably fine initially but for how long? The valve in my application failed and burned out my pump and your response is buy a new pump but keep everything else the same. Seriously???

Don't get me wrong I think you have a great product and really like it, I just don't have an application it fits. Every product has an application range it excels in but then also a range that just isn't a good fit. It seems however that blind faith in your product seems to blind you from this most fundamental fact. You clearly have a lot of experience and know your stuff, and therefore should be able to responsibly advise people not only when your product will fix their problem but also tell them when it won't.
 

Cary Austin

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Re: Wild pump-side pressure swings at startup
« Reply #9 on: December 16, 2022, 09:16:49 AM »
Again, I am sorry for your problem.  I do not have blind faith in anything.  I have over 30 years experience with several hundred thousand water systems, so I know what works and what doesn't.  !50 PSI back pressure with the CSV set at 55 is only 95 PSI differential.  That is right in the sweet spot for a CSV1A and will not destroy the valve.  Anything over 180 PSI would cause some wear on the CSV1A, so we use two CSV1A valves in cases like this to stair step the pressure down and make the CSV's last longer.  But you do not have enough back pressure to need two of the CSV1A valves.  Sand can also wear the seat in the CSV1A so that the minimum flow increases, making the tank fill time shorter.  But again, it takes a lot of sand to cause this, and then sand would be the cause of the problem, not the CSV.

Your pump was on a waterlogged tank long before you installed the CSV, which is where most of the damage came from.  Which BTW, was caused by too much cycling.  Then if you didn't notice the pressure surging after the CSV failed, that cycling also added to the demise of your pump.  It also proves how important the CSV is and why you should have some kind of device to detect cycling if there is a possibility of the CSV failing from sand or high differential pressure.  Our Cycle Sensor will protect the pump from rapid cycling if your whole house thing is not adequate for some reason.

I should also mention that the sand problem may also be caused by cycling in the past.  Cycling the pump surges the well level up and down and makes sand.  It is best to develop the well by pumping hard for hours or days if needed to get the sand out.  If you have enough sand to destroy the CSV it needs to be pumped out and/or filtered.  Filtering will help the CSV and other things but the pump is still having to deal with the sand.  Developing the well is best as that will keep the pump from having sand to start with.

Even if the CSV1A was destroyed by sand I will warranty it.  But 150 PSI back pressure is not going to hurt a CSV1A.  I will help you anyway I can.  Pumping sand and having a waterlogged tank in the past are your problems.  There is quite a bit of fudge factor figured into everything we say about out CSV's.  Tank sizes and run times are not that important as the CSV is very forgiving.  But you do need to start out with an undamaged pump and fairly clean water to pump.  Just let me know how I can help.
« Last Edit: December 16, 2022, 09:19:01 AM by Cary Austin »