Drain back system with a drilled well - Not draining back

[RoLo]

Hey folks, long time lurker, initial post. First, thanks for the wealth of information on this forum. It was very helpful having the combined experiences and opinions of this group with installing a drain back water system with a drilled well up here in Ontario, Canada.

I went with a drain back system because the cabin I bought 1) has a bladder-less tank already and 2) I can't dig below the frost line because of the Canadian shield. The pitless is almost below the frost line at 3' (frost line up here is 4'). The bleeder valve is at around 4', between the pitless and the pump (pump @ 80').

So I installed the system and it works great... except it's not draining back into the well. Snifter seems fine, even replaced it just to make sure. I installed yet another (now two) bleeder valves (brass, ball bearing type) but still my water feed freezes. I'm pretty sure I recently figured out why, it's the pump, I went too fancy. I picked up a Grundfos SQE which works like an absolute charm BUT I didn't realize it has a check valve built in, one that I have not removed. So, between that check valve and the head pressure, I'm pretty sure the bleeder valves do not 'release' because the pressure doesn't drop sufficiently in time (if at all) so the system does not drain back into the well.

As I see it, I now have two options.

Option 1) Remove the check valve at the pump. I'm not a fan of this option for a few reasons.

First, the water drains back all the way to the pump and I believe expels through the intake. That means the water flows in reverse over the impellers and, if the pump energizes while it's draining, I'm concerned about possible (long term) damage to the pump.

Second, the Grundfos manual tells you to CUT some tabs to remove the check valve. I don't like the idea of cutting anything from a near $1k pump dammit! I'd much rather take the head off the pump and try to remove the valve in a fashion that it could be re-installed if the situation changes in the future (which it might, but too long to explain). Little support from Grundfos in this regard, does anyone know if the check valve can be removed and re-installed without ordering replacement parts (Grundfos SQE)?

Third, I have to pull the entire line and pump out, around 100'. Not a deal breaker but I'd like to minimize movement in the well.

Option 2) Introduce a permanently open drain hole in the water line in the well. I've read some people simply drill a 1/8" hole in the water line inside the well for drain back. Of course water will escape this hole when the pump in energized but the pump can easily handle this and I'm open to introducing this inefficiency in the system. It means water won't pass the impellers and the head of the water will remain around 4' below the surface.. which theoretically shouldn't freeze.

My concern is that the pressure created by the pump exiting a 1/8" hole could lead to the hole expanding over time in the line or even etching the well casing, as the water would exit perpendicular to the line, which is vertical, so it would fire out horizontally and hit the casing of the well.. at pretty damn high pressures when the pump is energized. I could install a tee below the pitless, use a nipple to attach a 90 degree angle pointing down the well vertically and then end it with a nipple and cap with a 1/8" hole drilled in it. This would 'aim' the hole down the well to the water below.

Other concerns about the 1/8" hole is the possibility of it freezing (will the pressure blow off that ice plug?) or even the possibility of the hole becoming plugged with some debris.

So far, I'm leaning towards the permanent hole in the water line. I would love to get some opinions on this (vs remove the pump check valve vs some other solution?). Also, some suggestions and experiences around permanent drain holes in a drain back system if anyone has some.

Cheers!

 

[Reach4]

Can you monitor to see if water comes out of the bleeder? If so, try pushing the pin on the snifter valve to see if that causes water to dribble.

If your bleeder is not bleeding, you are also going to suffer from lack of air. What bleeder are you using? One thing that has bothered me is that it seems to me that they should leak a little on purpose. Otherwise, how does the water pressure drop to let the spring open the drain back valve? It would be interesting to have a combination vacuum/pressure gauge on the well side of the topside check valve. Even 0-100 psi pressure gauge would be useful IMP.

Another thing that could mess this process up is a small leak in the top side check valve. If the pressure tank maintains the water pressure through a leaky check valve, the drain back valve is not going to open.

Another thing to consider is to add insulation above your pipe. https://terrylove.com/forums/index.php?threads/preventing-water-feed-to-house-from-freezing.76513/ discusses that. That solution does not help the air-into-the-pressure-tank situation, however.

"The pitless is almost below the frost line at 3' (frost line up here is 4'). The bleeder valve is at around 4', between the pitless and the pump (pump @ 80'). "

Are you saying the bleeder is only a foot below the pitless? I am thinking maybe that should be lower. How does the altitude of the bleeder compare to the altitude of the snifter? I have never even seen a bleeder, however.

 

[Sponsor]

 

[RoLo]

Can you monitor to see if water comes out of the bleeder? If so, try pushing the pin on the snifter valve to see if that causes water to dribble.

If your bleeder is not bleeding, you are also going to suffer from lack of air. What bleeder are you using? One thing that has bothered me is that it seems to me that they should leak a little on purpose. Otherwise, how does the water pressure drop to let the spring open the drain back valve? It would be interesting to have a combination vacuum/pressure gauge on the well side of the topside check valve.

Another thing that could mess this process up is a small leak in the top side check valve. If the pressure tank maintains the water pressure through a leaky check valve, the drain back valve is not going to open.

Another thing to consider is to add insulation above your pipe. https://terrylove.com/forums/index.php?threads/preventing-water-feed-to-house-from-freezing.76513/ discusses that. That solution does not help the air-into-the-pressure-tank situation, however.

I'm using a 'bleeder orifice', BBONL75 (brass, 3/4", ball bearing style). I don't have access to the bleeder (while in use) as it's 4' down the well. I've tried to listen to see if I hear it leaking, but I don't hear anything. I agree that these should 'leak a little' because many modern submersible pumps include an integrated check valve, which keeps the water in the line and also the pressure, causing the brass ball in the bleeder orifice to stay in place and not drop, revealing the hole for the water to escape. This is why I'm asking for input on introducing a small hole to make this small leak.

One of the clues I had that the system was not dropping pressure was water exiting the snifter valve if the valve wasn't set to a high enough resistance. The final 'ah-ha' moment came when I read a small footnote in the Grundfos manual about a 'non drain valve'. It makes sense now of course, it's inefficient to let the water drain back into the well, so having a 'non-drain valve (ie. check valve) at the pump just makes sense for normal use cases. Always read the manual before installing a pump 100' down a dark hole kids, especially when it's your first off grid submersible pump install and you're getting fancy.

Adding insulation to the pipes above ground won't help in this case. The pitless is officially above the frost line because of this lump of rock called the Canadian shield, with a horizontal water line run of about 15' and then a 12' vertical run up the back of the cabin. The cabin is used on the weekends in the winter, with the whole system being drained with each visit.. or so I though. The only thing that isn't drained fully is the water line from the pump to the tank.

Thanks for the input, keep it coming!

 

[Reach4]

You always want a bottom-side check valve. If it is not built into the submersible pump, you add one just above the pump.

Thinking about your problem some more, I would try this test:

• Turn off the pump, while there is plenty of water in the pressure tank
• Push the snifter pin in, or even remove the valve core if flow is slow.
• See how much water comes out. It should be near zero, don't you think? If water continues to come out with the pump off, the topside check valve leaks faster than the bleeder does.

That could explain your symptom I think.

Adding insulation to the pipes above ground won't help in this case. The pitless is officially above the frost line because of this lump of rock called the Canadian shield, with a horizontal water line run of about 15' and then a 12' vertical run up the back of the cabin.

You have heard that insulation only slows the cooling, but cannot prevent freezing. That is not true in this case. The reason is that the earth below the insulation serves as a heat source, while the air above is a heat sink. If you can have enough insulation to keep the warmth coming up from being overcome by the cold from above, you could stop the freezing. This presumes the cabin itself does not freeze, or you drain that too. The reason for needing more width is that it keeps cold from creeping around the insulation.

There are people who say there is no such thing as cold, let alone cold flow. There is no such thing as a vacuum. There is no such thing as centrifugal force. Fie on them.

 

[RoLo]

You always want a bottom-side check valve. If it is not built into the submersible pump, you add one just above the pump.

Thinking about your problem some more, I would try this test:

• Turn off the pump, while there is plenty of water in the pressure tank
• Push the snifter pin in, or even remove the valve core if flow is slow.
• See how much water comes out. It should be near zero, don't you think? If water continues to come out with the pump off, the topside check valve leaks faster than the bleeder does.

That could explain your symptom I think.


You have heard that insulation only slows the cooling, but cannot prevent freezing. That is not true in this case. The reason is that the earth below the insulation serves as a heat source, while the air above is a heat sink. If you can have enough insulation to keep the warmth coming up from being overcome by the cold from above, you could stop the freezing. This presumes the cabin itself does not freeze, or you drain that too. The reason for needing more width is that it keeps cold from creeping around the insulation.

There are people who say there is no such thing as cold, let alone cold flow. There is no such thing as a vacuum. There is no such thing as centrifugal force. Fie on them.

Water leaks out of the snifter pretty well, but I believe the reason for that is that the check valve at the pump is not only keeping the water in the line, but keeping it pressurized. This pressure is greater than the pressure required for the bleeder valve to 'let go' and start draining, so it doesn't.

While I would agree (with my very limited experience) that you always want a bottom-side check valve in a normal submersible pump setup, it's keeping the water in the line (as designed), which is the opposite of what I want. I want the water to drain back into the well and I was counting on the bleeder to do this, but again, I think the pressure in the line is stopping the bleeder from opening. I could remove the valve at the pump but, if I do that, the water will flow back across the impellers which I have concerns about that I stated in the original post.

I hear you about the insulation, I did consider it. However, there's a couple key points that make this infeasible. The cabin is not winterized (don't ask), so I drain the entire system when I leave every weekend in the winter. I designed it this way, it's as easy as opening up a valve outside the cabin and puttering around with other things for 5 minutes while the system drains. However, the water line runs 15', buried around 1-2' below the ground and then 12' on the OUTSIDE of the cabin. I'm pretty sure that insulating this run, factoring in how often the water gets pulled through the line (not very), will save the line from freezing in -10 (celcius) weather. I think my time is better spent working out the last little glitch in the system, that is, making sure that line drains in an orderly fashion.

Have you ever heard of small holes being introduced in the water line in the well for this purpose?

 

[Reach4]

The check valve at the pump is normal and important. Professionals will agree.

What do you think about my suspicion that your topside check valve leaks?

Have you ever heard of small holes being introduced in the water line in the well for this purpose?

Yes. I think 1/16 is the number I have seen. It is instead of a drain back valve. You could make your own by getting a brass plug with the same thread as your bleeder. Drill a tiny hole in it. Yes, it would be squirting against the casing while the pump was running.

https://terrylove.com/forums/index.php?threads/avoid-well-system-freeze-up.39171/#post-278962
https://terrylove.com/forums/index....cycling-not-sure-wha-to-do.68571/#post-508946

 

[RoLo]

The check valve at the pump is normal and important. Professionals will agree.

What do you think about my suspicion that your topside check valve leaks?


Yes. I think 1/16 is the number I have seen. It is instead of a drain back valve. You could make your own by getting a brass plug with the same thread as your bleeder. Drill a tiny hole in it. Yes, it would be squirting against the casing while the pump was running.

https://terrylove.com/forums/index.php?threads/avoid-well-system-freeze-up.39171/#post-278962
https://terrylove.com/forums/index....cycling-not-sure-wha-to-do.68571/#post-508946

I don't think my topside check valve leaks. Last time I worked on the well while trying to diagnose this issue, the holding tank was full, I disconnected the pitless and the line drained but stopped, and I didn't see a pressure drop at the tank.

Would professionals agree that a check valve is normal and important in a drain back system?

Thats good news that you've seen a deliberate hole before for this purpose. I was thinking of putting in a brass plug with a hole drilled in it instead of drilling the PVC line itself. Should one be worried about the water squirting at high pressure every time the pump energizes, year after year?

 

[Reach4]

Try my test anyway when you visit the cabin. Can't hurt.

Would professionals agree that a check valve is normal and important in a drain back system?

Yes, top and bottom.

If there was no check valve in the well, the drain back valve would have no function.

While I would not worry about wearing out the PVC, maybe somebody else will think otherwise.

In that case, you could do as was suggested in a sump pump thread:
https://terrylove.com/forums/index.php?threads/sump-pump-vent-hole-spray-help.78459/

 

[VAWellDriller]

The check valve in the pump has nothing to do with your problem. Bleeders are a pain to keep working right. I am going to guess that you should lower the bleeder in the well....only 4' down is not much head to make the bleeder (or snifter) open up. Around here most people put them 1 or 2 joints of pipe down the well. If the well has a high static; just take the check out of the pump...and it will become the bleeder. You'll still need the top side check and a snifter valve or vacuum break.

 

[Reach4]

If the pump was still spinning backwards as the water fell, couldn't the pump start backwards? I guess it would take a brief power outage to make that happen.

 

[VAWellDriller]

If the pump was still spinning backwards as the water fell, couldn't the pump start backwards? I guess it would take a brief power outage to make that happen.

I've never witnessed it but I have had couple other drillers tell me that can happen.

 

[Valveman]

If the pump was still spinning backwards as the water fell, couldn't the pump start backwards? I guess it would take a brief power outage to make that happen.

More likely to break the pump shaft or coupling.

 

[Cacher_Chick]

Are you sure that there is no check valve other than the one at the pump? If the entire lateral is supposed to drain, where is all the air going to go when the pump kicks on?

 

[Boycedrilling]

A single phase motor should only run the one direction. A three phase motor would run in reverse if energized while back spinning. That is why we install anti-backspin timers on line shaft turbine pumps.

If you were to energize a single phase motor while it is back spinning, it would have a much higher probability or stripping the splines or breaking the shaft.

 

[RoLo]

Follow up. I didn't want to cut the check valve out of the pump, nor have water back flowing past the impellers. Instead, I drilled a 1/8" hole in a brass tee where I have the bleeder valve installed, in order to facilitate a pressure drop in the line when the pump shuts down. Now, the line definitely drains. Thanks for the suggestions.

 

[RoLo]

Are you sure that there is no check valve other than the one at the pump? If the entire lateral is supposed to drain, where is all the air going to go when the pump kicks on?

Yes, there's a check valve at the head of the system, just prior to the bladder-less tank. Yes, there's a snifter valve on the pump side of the check valve. There's an Air Control Valve on the tank to handle the air which is introduced into the line when it drains back.

 

[Cacher_Chick]

Yes, there's a check valve at the head of the system, just prior to the bladder-less tank. Yes, there's a snifter valve on the pump side of the check valve. There's an Air Control Valve on the tank to handle the air which is introduced into the line when it drains back.

Got it. I mis-read your initial post & was thinking you had a bladder tank.