Finding a blockage in a 50mm mdpe pipe ?

[scottishjohn]

would be good to get what evers blocking it out

so you can see what the blockage is made from .

how long did pump run before you got the first showing at the hole nearest the drainage field --if it was straight away 

 and  it is connected to 4 x100m legs then is it possible they are partially blocked if

,otherwise why would you have any flow from lower hole  until all legs were filled up ?

If its not been flowing for a couple of days then surely they would be empty ?.

If it were me i would want to totally disconnect small pipe and flush it through and make sure its not grease .

I know you say the septic should separate it --but it should n,t be blocked if only water flowing  anyway-- so something else is in there to block it 

do you have IC where 4x100mm connect to 50mm ?

 

 

Edited February 16, 2019 by scottishjohn

[Mr Punter]

Drain rods or Cobra rod must be easier than digging and then making holes in the pipe.

[Jeremy Harris]

13 minutes ago, Mr Punter said:

Drain rods or Cobra rod must be easier than digging and then making holes in the pipe.

 

I have to say I agree, poking a cobra up the pipe would have given a pretty quick indication as to where the blockage is, but @ProDave probably doesn't have a cobra to hand, and may well not be able easily get hold of one up where he is, so has to work with what he's got.

 

I could borrow a cobra from someone within half an hour, but that's only because I know a chap in the village that has one, and knowing him is only by luck, as he offered to lend it to me when he was walking past and spotted me struggling to blow a bit of string 30m up a run of buried 50mm cable duct (long story - basically young dickhead ground worker tied a crap knot in the middle of a length of pull rope.  I tried to pull a length of SWA through and the knot came undone....).

[ProDave]

So an afternoon digging and can't locate the pipe at any other location, it has to be either not where I am expecting it, or a lot deeper than I am expecting. My memory fails me as to it's exact location and I have no other photographs.

 

Re rodding from the bottom.  Where the pipe connects into the pump chamber it goes into a 90 degree fitting. So to rid the pipe, we would have to dig back quite some distance to get enough of a "loop" of the 50mm mdpe to get it to pull back out of the fitting, so that is not a trivial exercise.

 

When I turn the pump on, at the bottom, about 4 metres from the chamber, the fountain starts almost instantly.  At the top it takes a few seconds for the dribble to start.  When I drilled into the pipe in both cases the drill bit came out clean suggesting nothing other than water in the pipe i.e. no sludge or anything else.  The water that comes out in both cases is clean.

 

Now I have been pondering (clutching at straws)  I am wondering if it is just a case the new pump is not powerful enough?  This is pumping up hill about 2 metres, and the pump is down in the ground about 1.5 metres.  The new pump is an identical one to the old one  and is rated to pump up to a maximum of  8 metres.  But what if this pump is sub standard or even faulty?  Hard to prove that.

 

This is a much cheaper pump that the  original Italian pump, but a cheap one like this has worked previously But I am tempted to seek out one of the expensive Italian ones to try that?  

 

I had really wanted to do a third "hole" test at a mid point to draw a better conclusion.

 

Oh how I wish I still had a digger.

 

I do have another pump I might try tomorrow, it is not a new one but is my general purpose pump.  Trying that might prove or disprove another point.

 

 

 

 

 

[joe90]

@ProDave what’s your water pressure like?, if it’s like mine (6bar) could you not try connecting that with a hose and see if that shifts it ?

[ProDave]

13 minutes ago, joe90 said:

@ProDave what’s your water pressure like?, if it’s like mine (6bar) could you not try connecting that with a hose and see if that shifts it ?

The logistics of finding a set of fittings that will actually connect a domestic hose to any of the large bore fittings that the pump connects to seems very remote indeeed.

[Jeremy Harris]

5 minutes ago, ProDave said:

The logistics of finding a set of fittings that will actually connect a domestic hose to any of the large bore fittings that the pump connects to seems very remote indeeed.

 

Wooden bung with a hole in it jammed into the pipe?  Doesn't need much, and something just held together by hand might do the job.

 

Even a couple of bar from a hose would be around 20m head, so a fair bit more than the pump can shove out.  The pump may well stall if obstructed, too, which possibly reduces the pressure available to less than the rated head.

[Triassic]

We had the same problem on a Scout campsite, 1.5km - 50mm alkathene pumping main.

 

We used a portable fire pump to blast the crap out of the pipe.! We purchased a 50mm alkathene  to 1 inch BSP fittiing and connected this to the pipeline and the pump. 

 

The fitting cost around £6.50 on eBay.    Mains pressure might be good enough.

 

Plan B would be to purchase a 60m roll of the cheapest 15mm pipe you can find and use that to rod the 50mm pipe. If it were me I’d connect one end to the mains and flush and rod in one go. Wear appropriate PPE.

 

 

Edited February 16, 2019 by Triassic

[Declan52]

Can you get the hose to the high section so gravity will help. 

[ProDave]

Whatever we do is going to be some serious hard work just to get at one end or the other of the pipe.

 

The top end is really a non starter, that means digging deep in the now ploughed field, definitely a job for a digger not by hand.  The bottom end as I say needs digging back far enough to be able to to bend the mdpe just to pull it back out of the fitting.

 

The only realistic hope of getting a mains hose to this system is to try and make a connection to the short "flexible" hose that the pump connects to. At the top end it is a quick release fitting that came with the tank, and at the bottom it's 1 1/2" BSP

 

This has to be a lesson for all those that can avoid it, how utterly crap pumped outlet systems are.  I am SO glad the new house does not have a system like this, and so glad we did not end up with the original plan of a umped outlet to a filter mound,

[ProDave]

I am more tempted now to try just buying one of the original Italian pumps as was supplied with the pump chamber when new.  Not quite as expensive if you buy direct from Italy  https://www.ebay.co.uk/itm/POMPA-SOMMERSA-EBARA-RIGHT-100-MA/264139492924?hash=item3d7ff0ce3c:g:ufwAAOSwBZBcPYFh:rk:2:pf:0

 

These people offer to beat any genuine on  line quote so I have contacted them to see if they will beat that ebay offer https://www.prestigepumps.co.uk/manufacturers/ebara-pumps/?gclid=EAIaIQobChMI7O36i_zA4AIV1IXVCh2ffAvKEAEYASAAEgIDivD_BwE

[Declan52]

Do you know anyone with a small compressor you could connect it and see if it blows clear.  A joiner or maybe even a mechanic with the portable version for inflating tyres. 

[Nickfromwales]

2 hours ago, ProDave said:

The logistics of finding a set of fittings that will actually connect a domestic hose to any of the large bore fittings that the pump connects to seems very remote indeeed.

Just go and buy them? A hell of a lot easier and quicker than digging all day ?!? What about a suction pump and try pulling the blockage back to you?

[ProDave]

2 minutes ago, Nickfromwales said:

Just go and buy them? A hell of a lot easier and quicker than digging all day ?!? What about a suction pump and try pulling the blockage back to you?

Well the easiest way would be 1 1/2" BSP female to a fitting a standard hose will go onto.  Any ideas?

[Nickfromwales]

Chuck a hozelock fitting onto the end of the hose and that gets you to 3/4". 

one of these screwed into the HL fitting

some barrel or other then

one of these ?

[Nickfromwales]

Or hose to a spare outside tap which gets you backwards to 1/2"

[ProDave]

I have scoured my various boxes of plumbing fittings and come up with a collection of fittings that will get me from my female BSP to 15mm copper,  with a bit of stretching and a jubilee clip the hose should go on that.  At the other end the hose fits properly to the outside tap at full mains pressure.

 

I will give that a go tomorrow and see if I can flush this thing through.  Using my hole in my top pipe as a guide. I will be happy if I can get a fountain spurting from that.

[dpmiller]

if you can produce a vacuum of some kind that might be worth a try too, pull the obstruction back. Know any aircon guys?

[scottishjohn]

2 hours ago, Declan52 said:

Do you know anyone with a small compressor you could connect it and see if it blows clear.  A joiner or maybe even a mechanic with the portable version for inflating tyres. 

a pub gas bottle if no compressor ?

do you have a connector to rejoin 50mm if you cut it to inspect or push something up it from other end.

any boy racers local that would have some samco turbo hoses+clips ,or a hose of an old car or something 

 

a lesson to be learnt here--inspection chamber where 50mm joins the 100m manifold for drainage field array ---(noted for my my system )

do I understand correctly that the drainage field array is uphill from septic tank ,so when no pump working the water will try to go back to the pump chamber  not just seep out of perforated pipes into ground 

[scottishjohn]

44 minutes ago, dpmiller said:

if you can produce a vacuum of some kind that might be worth a try too, pull the obstruction back. Know any aircon guys?

very hard to produce a good vacumn and thats alot of volume of pipe to evacuate +it might collapse? --lot easier to pressurise

Edited February 16, 2019 by scottishjohn

[ProDave]

Cutting it is a last resort.  I can't keep reiterating just how big and stiff 50mm mdpe is.  In  order to pull the pipe apart enough to insert an mdpe coupler I think you are going to want quite a length of pipe uncovered to be able to bend it enough.

 

I will post back how tomorrows flush attempt goes.

 

[joe90]

Best of luck tomorrow @ProDave

[Pete]

Do you know any of the local fire service, they will blast it for you.

[ProDave]

Okay the test results are in. And they are inconclusive.  I need some help to check my thought process:

 

With the mains water connected via the garden hose and my bodged set of plumbing fittings. I get exactly the same, just a trickle from the top test hole. (the bottom one is now plugged and holding).  But go in the house and you can hear a good flow of water exiting the outside tap.

 

So I am beginning to wonder if I am barking up the wrong tree and there is no blockage.  The point I have drilled the top test hole is almost certainly the highest point the pipe gets to, from there is is a gentle downhill run to the soakaway in the field that can't be more than a few metres away.  There it opens up to 4 runs of 110mm perforated pipe where it will drain freely.

 

So even if things are flowing properly, there won't be much pressure in the pipe at that point will there, so would I expect more than just a trickle from a small hole drilled in the top of the pipe?

 

I came to the conclusion originally that there must be a blockage because after 10 minutes of pumping with the new pump, the level had not gone down noticably.  I am now veering to the other theory that this is just a rubbish pump and barely able to achieve a significant flow at that head.

 

I am minded to sport £200 on the Italian pump before doing any more.

[Jeremy Harris]

Is there any way you can do a crude test to see what sort of head the pump can deliver? 

 

Perhaps pointing a (restricted) pipe up vertically to see how high it will raise a fountain might give an indication of how well it performs with the outlet restricted?