epsilonGreedy Posted March 6, 2019 Share Posted March 6, 2019 How are the tenants fairing? They have been crossing their legs for a couple of weeks now ? Link to comment Share on other sites More sharing options...
epsilonGreedy Posted March 6, 2019 Share Posted March 6, 2019 18 hours ago, ProDave said: I am now torn between buy some more drain rods so I can really rod the whole length from the bottom, or open up a big pit at the top and cut into the pipe there and rod it down. How old is the drainage field or how many man-years of effluent has it dealt with? Also when you last had problems with a suspect pump was it towards the end of winter? Link to comment Share on other sites More sharing options...
ProDave Posted March 6, 2019 Author Share Posted March 6, 2019 The drainage field is now 15 years old. Pump failure has been at random times. The first one lasted 7 years (that was the original expensive Itallian one) the second one lasted 5 years, that was a cheap one and a post mortem dismantling revealed the steel casing of the motor had rusted through letting water in. The next one failed after a year but upon removal it was found to have fallen over onto it's side so we suspected that was the cause, the float switch would not have turned off and the motor ran until it expired. It is really only the recent failure at 1 year old that has been unexplained, but of course this blockage would explain that as it would have been working hard not moving much, until it expired. If the rain stops I will be going to try roding with the PEX pipe and hose "lance" Link to comment Share on other sites More sharing options...
ProDave Posted March 7, 2019 Author Share Posted March 7, 2019 Okay another day another disappointment, a BIG disappointment. So unrolled my coil of PEX pipe from the top down to the bottom and marked it with tape where I expected it to "end" I then sent the PEX pipe up from the bottom. It met no particular obstruction. I kept on feeding it in and it just kept going, way past my mark by many many metres before it did eventually come to a hard stop. I am pretty certain it had come to the end of the mdpe pipe and down one of the perforated drain pipes of the soakaway. At that point I cut the coil of pipe and attached the hose to the end and turned on the mans water. Water was flowing up the hose but none came down the mdpe pipe. As I would have expected it was flowing into the soakaway. Keeping the water running I drew the house out and back a couple of times. Some black water did come down, but not a lot. So the pipe is clear to the top and into the soakaway. I re connected the pump and tried it. It is pumping away, but oh so very slowly, way slower than it used to. Something is still not right. The odd thing is there is still not much coming out of my "test" hole at the top of the mdpe pipe run. More than before but still not a fountain. I think it is time to talk to the farmer and get a digger in and see what is going on down there. Worst case that I am dreading is needing to re lay the whole drainage field. Link to comment Share on other sites More sharing options...
Onoff Posted March 7, 2019 Share Posted March 7, 2019 There's not a blockage the house side of the pump? Link to comment Share on other sites More sharing options...
ProDave Posted March 7, 2019 Author Share Posted March 7, 2019 35 minutes ago, Onoff said: There's not a blockage the house side of the pump? I have cut through the 50mm mdpe at the bottom of the hill where I now have a slip coupling. If I loosen that coupling and slide it along, water fair gushes out of the exposed pipe, so I can't see it is a problem at the bottom end. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted March 7, 2019 Share Posted March 7, 2019 This really is a bit of a puzzle, isn't it? It's hard to see what could be causing this, as it seems that a blocked pipe has been ruled out. Fitting a pressure gauge in a tee in the pump outlet pipe would show whether the pump is delivering the specified head. Ours sounds similar to yours, a stainless steel submersible one, and that has a 7.5m maximum head, so around 0.735 bar. Fitting a 1 bar pressure guage should give an idea as to whether the pump is working properly, although your small drilled hole in the pipe should be almost as good an indicator. From what I can recall about the pressure curves for centrifugal pumps, they can hydrodynamically stall, so that if the back pressure momentarily exceeds the maximum the pump can deliver, the pressure falls off again, rather than following the rpm being proportional to pressure line as rpm increases. Link to comment Share on other sites More sharing options...
scottishjohn Posted March 7, 2019 Share Posted March 7, 2019 1 minute ago, JSHarris said: This really is a bit of a puzzle, isn't it? It's hard to see what could be causing this, as it seems that a blocked pipe has been ruled out. Fitting a pressure gauge in a tee in the pump outlet pipe would show whether the pump is delivering the specified head. Ours sounds similar to yours, a stainless steel submersible one, and that has a 7.5m maximum head, so around 0.735 bar. Fitting a 1 bar pressure guage should give an idea as to whether the pump is working properly, although your small drilled hole in the pipe should be almost as good an indicator. From what I can recall about the pressure curves for centrifugal pumps, they can hydrodynamically stall, so that if the back pressure momentarily exceeds the maximum the pump can deliver, the pressure falls off again, rather than following the rpm being proportional to pressure line as rpm increases. JS-- you are correct --thats exactly what will happen --needs flow to stop it stalling Link to comment Share on other sites More sharing options...
Declan52 Posted March 7, 2019 Share Posted March 7, 2019 Can you leave the pex pipe in place and connect it up to the pump and see if it pumps along that. Link to comment Share on other sites More sharing options...
scottishjohn Posted March 7, 2019 Share Posted March 7, 2019 when you relay the drainage field maybe you will consider fitting a grease trap ? rented accomodation they ain,t worried what they put down the drians not on sewage pipe but on all the other drains from sinks etc before ti joins to septic system Link to comment Share on other sites More sharing options...
ProDave Posted March 7, 2019 Author Share Posted March 7, 2019 5 minutes ago, JSHarris said: From what I can recall about the pressure curves for centrifugal pumps, they can hydrodynamically stall, so that if the back pressure momentarily exceeds the maximum the pump can deliver, the pressure falls off again, rather than following the rpm being proportional to pressure line as rpm increases. I am exasperated by this now. All I can think is the drainage field is clogged so the pump flow stalls and as you say then the centricugal pump stalls. The next logical step has to be excavate in the field to find the end of the mdpe as it enters the drainage field to test flow (with it uncoupled) and examine the state of the drainage pipes;. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted March 7, 2019 Share Posted March 7, 2019 Just now, ProDave said: I am exasperated by this now. All I can think is the drainage field is clogged so the pump flow stalls and as you say then the centricugal pump stalls. The next logical step has to be excavate in the field to find the end of the mdpe as it enters the drainage field to test flow (with it uncoupled) and examine the state of the drainage pipes;. I don't blame you for feeling exasperated, as it sounds like a complete PITA. I'm wondering if the pump may have always been operating close to the point where it could stall, and so just a small increase in back pressure, perhaps from a slight reduction in the permeability of the soil surrounding the soakaway field drains, has been enough to be the "straw that breaks the camel's back". Opening the pipe close to the end, where it joins the field drain pipes, would give an indication as to whether it's increased back pressure causing the problem. My guess is that if you do this you will find that the pump is fine pumping up the whole length of the pipe, with a good flow rate. Link to comment Share on other sites More sharing options...
scottishjohn Posted March 7, 2019 Share Posted March 7, 2019 could it be the drainage gravel around the soak away pipes has compacted,if farmer is ploughing ever year over top of it ? Link to comment Share on other sites More sharing options...
jamiehamy Posted March 7, 2019 Share Posted March 7, 2019 Or the field/pipe has partially sunk in the middle and all the water pools in a small undulation and runs back/blocks? Link to comment Share on other sites More sharing options...
ProDave Posted March 7, 2019 Author Share Posted March 7, 2019 The drainage field was made with fist size rocks not gravel so I doubt that is clogged, And there was a pretty good fall making it deeper the more it goes into the field so I dobt it has sagged and pooled. I have left a message with the farm manager to discuss it and have the local digger man coming to see me soon to work out a plan of action. Link to comment Share on other sites More sharing options...
epsilonGreedy Posted March 7, 2019 Share Posted March 7, 2019 4 minutes ago, ProDave said: The drainage field was made with fist size rocks not gravel so I doubt that is clogged Could it be saturated? This is why I asked the other day if prior problems coincided with winter months? Link to comment Share on other sites More sharing options...
ProDave Posted March 7, 2019 Author Share Posted March 7, 2019 Just now, epsilonGreedy said: Could it be saturated? This is why I asked the other day if prior problems coincided with winter months? I doubt it, but digging will tell us that. It's not had significant input for a couple of weeks so even if it had been overloaded it should have gone down by now. Link to comment Share on other sites More sharing options...
epsilonGreedy Posted March 7, 2019 Share Posted March 7, 2019 1 hour ago, ProDave said: I am exasperated by this now. Just throwing in a random thought at this point. Is it possible a vacuum is building up on the house side of the pump when it operates due to a blocked breather pipe? Link to comment Share on other sites More sharing options...
ProDave Posted March 7, 2019 Author Share Posted March 7, 2019 Just now, epsilonGreedy said: Just throwing in a random thought at this point. Is it possible a vacuum is building up on the house side of the pump when it operates due to a blocked breather pipe? No the pump chamber has a very loose fitting lid and for a lot of the testing the lid has been off anyway. Link to comment Share on other sites More sharing options...
Vijay Posted March 8, 2019 Share Posted March 8, 2019 Would it help to fit a small wifi camera to the end of the pex tube and see what's in the pipe? Something like https://www.ebay.co.uk/itm/Mini-Spy-IP-Camera-Wireless-WiFi-HD-1080P-Hidden-Home-Security-Night-Vision-UK/253983852854?hash=item3b229e0936:m:m8T1pmIJAwIaXUhqLAsyUQw Link to comment Share on other sites More sharing options...
ProDave Posted March 11, 2019 Author Share Posted March 11, 2019 Okay all sorted this morning. Today, being the one good say in the weeks weather forecast, we set off with the intention of digging a hole in the field, But SWMBO talked me out of it. It was that fountain, or lack of fountain, at the upper test hole. WHY were we not seeing a fountain at that upper test hole. Se convinced me digging a massive hole by hand was going to be a waste of time. So we looked again at what was down at the bottom. We decided to scrutinise all the pipes and fittings within the pump chamber. There was this innocent looking fitting. It came as part of the pump chamber plumbing. It went between the 50mm mdpe elbow fitting, and the quick release pump hose fitting. There was never any mention of it being anything special. To me it just looked like they needed a female to female coupling and used a tee with a blank plug. It didn't look like it was any form of strainer. Once I had unscrewed it from the pump chamber it was obvious there was a problem, you could not see through it. . When I cleared it out, there was this what looks like a flap, wedged tight at the top of the fitting with various bits of debris packed in behind it. So it looks like this was a non return flap valve. There was never anmy mention with the pump chamber that it had one supplied, and it never worked as a non return valve as I fitted one attached to the pump at the bottom of the hose because it needed one and the one they didn't tell me they had supplied never worked. I made no attempt to put the flap back, I just cleared it out and put it back together as a dumb straight coupler. It is all now working, and now we did get a fountain out of the top test hole, albeit not very high. But the pump now clears the contents away up the hill into the soakaway at about the rate I always remember it working at. A big relief that the soakaway appears to be functioning correctly and no need to dig up the field. The digger man has been stood down. 4 Link to comment Share on other sites More sharing options...
Jeremy Harris Posted March 11, 2019 Share Posted March 11, 2019 Bugger, what a swine of a thing to find after all that trauma. I'm kicking myself, too, as our unit has exactly the same brass flap-type non-return on the pump outlet; I should have thought of it sooner, but the memory was only triggered when I saw your photo. Link to comment Share on other sites More sharing options...
ProDave Posted March 11, 2019 Author Share Posted March 11, 2019 The bugger here is it was never described in the documentation with the pump chamber that it WAS a non return valve, although the instructions said you must fit a non return valve. That led me to buy a larger one and fit it on the outlet from the pump a short time later. And this one has never worked as a non return valve so the flap may have been detached all this time. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted March 11, 2019 Share Posted March 11, 2019 Could be the reason it's gone through a couple of pumps, too, perhaps. Maybe they've been working against that partial blockage right from the start. Link to comment Share on other sites More sharing options...
ProDave Posted March 11, 2019 Author Share Posted March 11, 2019 Yes could be. The blockage is certainly the reason for the recent pump failure. It has the Itallian pump in now, identical to the one originally fitted so I hope this will give a good service life as now everything seems in order. I must say though I am very glad we ended up with a system that needs no pumping in the new house (the original plan had been a pumped outlet to a filter mound) Although we never got to dig the big hole and inspect it, the soakaway does now appear to be draining freely. Link to comment Share on other sites More sharing options...
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