Lightening blowing press. release valve
Good Day,
I have a 3-year old home with a drilled well and a submersible well pump. The well driller installed a Grundfus pump and control system. All runs well except when we have a nearby lightening storm. On at least 6 occassions in the past three years lightening has hit very near to my home and has caused my pump to surge to the point that it has blown the pressure release valve on the system.
The well driller and my plumber have no idea why this would be happening. I’ve spoken to a number of folks around town and thus far have not gotten any definitive answers. The supply house that sold the system to the well driller suggested a more robust pressure relief valve (the valve that was originally installed needed to be dialed in – the tech at the supply house suspected that the installer forgot to dial it in and therefore it was probably set at 75 psi). I installed a 100 psi valve and since then, the valve on the water system has been fine, however, during the most recent storms the valve on my rennai water heater has been blowing.
I plan to install a more robust valve on the water heater next but would sure like to know how/why the lightening is causing my pump to surge. Can anyone shed any light on this for me???
Thank you!
Replies
Have you got a sufficient electrical gound at the well? Pump surge seems electric with the increase in pressure a sympton and not the culprit.
I'm not sure how to answer your question. The top 20-30 ft of the well is lined with metal casing (does that count as a ground) and I assume that the installer grounded the pump - other than those, I don't believe there are any additional grounds.
The pump is usually insulated from the casing.
By the way - I may not have been clear in my original post, but I agree with you that the increase in pressure is a symptom. I'm wondering what causes the electrical surge and how I can prevent it in the future.
Thanks for you reply!
Electicity gets to your pump somehow and there's probably a small panel with at least a shut off at the well. If there's errant electricity getting into that underground wiring from the lightning it coould lead to your problem (could be an indicator of problem with the wiring). Is there a wire and grounding round into the earth at that panel? An earth ground is not required at that panel unless it feeds other circuits but it's an easy thing to install.
There's some electrical gurus here that may have other & more accurate ideas. Let's hope they check in.
This pump unit has a "control" box mounted in my basement. I don't believe there is a shut off on that control box - to shut it off I've been flipping the breaker in my electical panel. The control box is grounded via my whole house ground. As for the wiring within the well, I can only assume that it was run correctly and that is it properly grounded...
Where are you (profile info?) anyway? Somewhere up North? I made a couple of assumptions thinking you have a deep well. Is this a new well or older? Assuming the pump is down inside the well and the well casing is around 6-8" in dia: One common point of elect problems with wells is the wiring leading own to the pump at the bottom of the well. The wiring rubs against the casing walls if not secured to the feed pipe every time the pump runs (torque casues it to twist and swing around. There's also spacers that center the pipe in the casing to help prevent the swinging. Did the well guy check the wiring? He'd have to pull the pump to do this (assuming it's at the bottom of the well).
Speaking of whole house ground, is it intact? I've seen a few burned through from close lightning strikes (that's the bare copper wire (#4?) between the panel & the rod).
Something is energizing the pump motor to cause it to spin up pop the PR.
I live in central Maine. The well is 3 years old and ~200' deep. The pump is installed ~25' from the bottom of the well and the hole diameter is 10" (I think - it may be 8"). The top 20-30' is cased, the remainder of the well is through bedrock. I recall the installer attaching 3 or 4 anti-torque devices to the plastic water line - two right above the pump and the two others equally spaced ~10-20' above that. I also recall the installer taping the wiring to the water line every 10' or so as it was dropped down the well.
The installer has not checked the wiring - when I spoke with him after the first incident (~1 month after the intial installation), he felt confident that the install was fine. He was not able to offer any ideas why this was happening.
I am fairly confident that the whole house ground is intact although I will check it this evening.
Is this system a conventional installation with a pressure tank and pressure switch (usually near the tank) which turns the pump on and off?When you get a "surge", do you have to do anything to reset things? Do the pressure relief valves just spit for a few seconds, or do they run until you turn the pump off?
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Please see my resonse to junkhound regarding the system.
When the pressure valve gives the water runs continuously until I kill the power to the pump. After I kill the power, I assume that the relief valve resets because when I restore power to the pump all is fine until the next nearby lightening strike...
Yeah, it sounds like the electronic controls for the variable-speed pump are getting scrambled. You should add a separate mechanical over-pressure switch that cuts power to the pump at 70-80 PSI, and also add whatever surge suppression/noise suppression you can manage. Hard to guess where/how the surge is getting into the wiring, though -- could be inductive.You DON'T want to simply add higher-pressure relief valves -- that's just going to make matters worse.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Thank you all for your help! I will see about picking up an over-pressure switch over the weekend. I won't know whether or not it solves my problem until the next thunderstorm - I will post back at that time.
Thanks again!
"Thank you all for your help! I will see about picking up an over-pressure switch over the weekend. I won't know whether or not it solves my problem until the next thunderstorm - I will post back at that time."That won't "solve" the problem. But can cause it to automatically reset.To realy solve the problem surge protectors at the controller is needed..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
LOL!
So all I need to do in insert a surge protector between the electrical supply and the controller???
That and also possibly one on the motor supply. If possibly that the noise is getting in from that side and causing the controller to lockup.I would contact the manufacture of the control and see if they have an technical bullitens about this problem..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
The problem is you don't know where the problem is. It would be prudent to add a surge suppressor (you can get one that wires in via a junction box) for the pump circuit, since whatever surge you're getting could eventually damage the electronics or the motor itself. But the surge could be getting in somewhere along the line from the pump controller to the wellhead, either by direct contact or inductively. (Eg, a strike that hits the metal well casing will induce noise into the pump wiring.) And a simple surge suppressor may not prevent your problem, since it's apparently more of a noise problem, and a surge suppressor won't control noise very well.You really need something like this:http://www.squared.com/us/products/surge_protection.nsf/unid/081CEEA1FA1F148D85256BB800735AC7/$file/surgelogiclchome.htmBut even with that there are no guarantees, since the source of the noise is unknown.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
My system is a Grundfos CU 301. It has a pressure sensor that in this case is installed in the pipe between the pump and the bladder (the manual indicates that it is supposed to be installed on the other side of the bladder - I have no idea if that is significant). The controller box is set to provide up to 60 psi of water pressure and at rest, an in-line pressure valve located between the pressure sensor and the bladder reads 70 psi.
I will contact Grundfos and see if they can offer any insight regarding my problem. In the meantime I will at the very least install surge suppression on the pump circuit and look into the suppressor that DanH suggests.
Again, thank you all for your help!
Lightning is hitting the water line and causing water to boil?
Is it a variable speed/constant pressure pump with electronic controls that relay the pump speed via the supply wiring?
We have three electronically controlled ceiling fan/lights and nearby lightning strikes often will cause the fans to change function, or come on in the middle of the night, or quit working until recycling the control switch. And on occasion have scrambled a circuit board, $70 and disassembly.
If your system has similar control functions you may want to investigate a surge suppressor in line before the pump control and voltage supply and neutral.
...............Iron Helix
A lightning surge will not cause your pump to "surge" and increase the water pressure, it does not work that way, no way lightning would cause the pump to run faster for the amount of time it would take to build overpressure.
There is a possibility that a lighning surge could 'latch' your electrical pressure switch 'ON' for a while - you've supplied no details on the pressure switch for the pump - electronic or mechanical??? Usually that type of switch latching action would be welded contacts on a mechanical switch (you would need to fix the switch to stop the pump from running) or electronic latchup (turn power off and then back on).
Dan's premise on a pressure surge due to water heating (or pressure surge due to acoustic pressure/thunder from very close lighning) is the most likely cause if you have not had any latching of your pressure switch.
Reset of relief valves is the solution as you already found out on the water system valve. The fact that that worked probably precludes the latch scenario, but the pump may not be able to reach the new pressure setting - double check to be sure your pump does stop running when the set pressure is reached.
I will do my best to answer your questions - I wasn't thinking this morning and forgot to bring the system specs with me.
The sytem has a very small water bladder (I would guess it's ~1 gallon in size). It is designed so that when a valve is opened anywhere in the house, the water pressure is provided directly by the pump. So, anytime I turn on a faucet, the pump runs and provides the necessary pressure to feed the faucet - water pressure is not provided by the bladder. If more than one faucet is open, the pump provides additional pressure (there is no noticable decline in head at any one faucet when others are turned on in the house). So the pump only runs when there is an "open" in the system. There is a setting on the controller which determines the max pressure that the pump will provide - I believe it's set at 60 psi.
I don't profess to know much about electical motors, but I am guessing that what I described would suggest a mechanical switch??? Sorry I can't provide more details at this time.
"The sytem has a very small water bladder (I would guess it's ~1 gallon in size). "
I wonder if that's not a large part of your problem. A larger tank would give you more of a buffer for pressure changes.
A larger tank would also give you more water reserve when you have a power failure.
I wrote a few children's books.
Not on purpose, though.
I've had lightening fry my pump control box...yours may only be partially cooked...and I'm with Boss on the small bladder tank. Is it the only pressure tank? Someone's got it in for me, they're planting stories in the press
Whoever it is I wish they'd cut it out but when they will I can only guess.
They say I shot a man named Gray and took his wife to Italy,
She inherited a million bucks and when she died it came to me.
I can't help it if I'm lucky.
Put on a big tank and you might end up with pressure cycling up and down.This is a much different type of system.The pump is a variable speed drive. It will start off slow and ramp up to whatever the depend is. Then as you close off valves it the pump will slow down and not stop until the the flow stops.The tank does not realy store water. It is only their for the first and last couple of seconds..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Sco,
I believe Dan H has nailed the problem. Check on the condition of your ground rod system at service entrance meter. Some grounding systems only have one grounding rod. Regardless of requirements I would insist on three ground rods properly buried and connected per elecrical code. Also have the ground system megged for resistance to make sure that there is a good earth ground.
Lightening seems to be following the path of least resistance through your water system to the well. The piping and water in the pipe is superheated from the bolt of lighting and this causes a brief pressure surge from the water flashing to steam.
Further remediation can be done with a whole house electrical surge suppressor installed in your service panel.
Power company could also check for proper grounding of the transformer that serves your house.
Also get back to your normal house pressure setting for your well water pressure. 100 psi relief or cutout is far to high for domestic water supply.
Regards,
Virginbuild
No, if it was the burst of steam thing the valves would only blow briefly. Later posts show that the valves keep running until the pump is reset, indicating a problem in the pump controls.But improving grounding for the service entrance couldn't hurt.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
I did a visual inspection of my grounding system and all "looks" fine. I did the install myself (I know, I know, that's probably my problem right there) - I drove two 8' rods into the ground ~8' apart. One of them went 7+ feet and the other went around 6.5 feet before encountering bedrock or a large obstruction. Last June when I was digging holes for a deck foundation I encountered water at 3-4 feet below the sureface, so I am fairly confident than one or both of the rods are sunk below the water table.
I have to wonder if my ground was not adequate wouldn't I have encountered other electrical problems besides the one with my water system? Or is it possible that because the resistance through my water system is so low, it is in essence protecting other electronics within the house by taking the brunt of the surge? If I understand Virginbuild correctly, while my ground may be OK - there may be less resistance through my water system and down my well and that's why the lightening is affecting my pump/water system???
As of now my plan is to install a whole-house surge suppresor and also install a third grounding rod off of my existing rods. As for the pressure relief valves, the valve on my ground water system is a fixed 100 psi valve. For what it's worth - the local Grundfus distributor informed me that that is correct for my system which is set to provide up to 60 psi to the house. I haven't touched the valve on my water heater and don't intend to.
Thanks again for all of your help!
Sco
Keep us posted if you can. 1 more thing out there in left field, have you checked the ground wire between the house ground and the connections at the well? Should be showing very little to zero reistance.
Here's the latest on my lightening problem - I wound up speaking with a regional Grundfos technical representative (he works for an independent company that deals with many pump suppliers including Grundfos) yesterday who was completely stymied by my problem. He called the Grundfos factory and within ~5 minutes was back to me with questions regarding the serial number of my controller. Well, it turns out my controller was amongst the early models that were produced - the models that did not include some sort of pressure sensor (I apologize, he went right over my head when he described it) that supposedly would prevent the behavior that I've been seeing.
I naively assumed that they would ship me an updated controller and I would ship the old one back. However, when I asked the tech about it, he said that he didn't think the factory was inclined to do so. He said he would call the factory for me (he also gave me the direct number of the factory so if this doesn't work out I can call them myself - for what it's worth) and see what he could do. When the factory still balked, he called the Grundos regional sales manager and is now waiting on a return call from him.
I have real mixed emotions right now. I'm happy that we may have found a solution; pissed at myself for not contacting the company sooner; a little apprehensive that this may not actually fix my problem; and disappointed at the initial response from Grundfos. I'm prepared to contact the well contractor that installed the unit and the local Grundfos distributor - I am hopeful that if necessary they will put pressure on Grundfos to do the right thing.
I don't think I'm being unreasonable to expect them to replace the unit? I liken it to any other consumer product that was found to be defective or not up to specs - typically a recall notice is issued under those circumstances.
Thanks fer the update. It's always nice to hear how things turned out.
Forgiving is not forgetting; it's letting go of the hurt. [Mary McLeod Bethune]
Do Not change out pressure relief valves to one with higher ratings. They are there at the pressures they are to protect they system. You are much better off with the valve on your water heater blowing off, than the heater or some other part of the pumbing blowing up.