Blocked Saniflo outlet pipe

[Zippymark]

I've got a job with a saniflo that's not put pumping away, the cause of which being the waste pipe downstream of it being blocked. Not entirely, but only letting mains pressure through at maybe 1ltr/min say. It's run in copper right out to the stack as far as I can see, so it should be able to take a bit of pressure. I've disconnected the saniflo from the copper pipe so it's not involved and I'm alternating pouring drain acid down it (yes I know they won't recommend this) and linking it to the shower hose to run mains pressure hot water down it, which has improved it slightly but it's still clearly restricted.

I'm wondering if it's not a 'blockage' as such and more a build up of something restricting the size of the entire pipe, has anyone got any ideas of what to try and clear it with? Would it be scale, in which case I have DS-3?

Thanks for any help

 

[Best]

@rpm possibly could advise.
Wonder is the end of pipe at soil stack blocked?

 

[Rob Foster]

Pub line cleaner is great, but can you see all of the pipe run ?
Can you get to the other end. Alternative is the old routine
cut in half and see which end is blocked ....its quite a good earner...loads of labour hardly any parts....what od is the copper then....Rob Foster aka centralheatking yank it out of the stack and see what happens....get some gauntlets and get a hose running

 

[Zippymark]

I'd not heard of pub line cleaner, I've just had a quick look, it seems to be caustic soda based. It's 22mm copper at either end, it runs under the floorboards inbetween, the bends I can see are pulled which is good but I don't know what's happening under the floor. There isn't any vertical rise though, probably just fairly flat all the way with a few turns. I have access to either end, my other idea was get a long enough hose and link my powerflush machine to it, I'm just not sure I want what'll come out going through my machine haha. Or what chemicals to use.

 

[Zippymark]

Oh and it connects to 1 1/2 plastic waste for the final section where it connects to the stack, with an access point so I've had that off and you can just see the water trickling past so it's somewhere (or all of) the pipework

 

[Burger]

All depends on what is causing the blockage, if it’s solid enough (like I’ve seen some caustic sodas go) it won’t move, and maybe only way to go is renew section of pipe where it’s blocked.

 

[Zippymark]

Yeah It's hard to say really. My gut feeling is it's kind of just restricted all the way down, like a calcium build up or something? It was a bath, basin and toilet running through it, no washing machine. With alternating drain acid and mains pressure I've got the shower hose connected to one end and its flowing quick enough to keep an old biasi alight for hot water, so it's getting there.

This property had the exact same problem about a year or so ago, so it's reoccurring.

I've never really used caustic soda, can you mix it with water? What I'm thinking is connect my powerflush machine either end and let something circulate through it for a few hours.

 

[rpm]

Hard water area? I've seen 22mm copper so heavily furred you couldn't get a bic biro through it.
Most blockages will be at the start of the run or the end providing no sharp elbows of course.

 

[rpm]

Just had time to revisit the thread, are you certain that the problem is not inside the sani?

 

[Zippymark]

East London so yeah, pretty hard water. The Saniflo is about 10/11 years old so it may not be pushing at full force any more, which may be a contributing factor, but as I say, even with that disconnected and mains pressure running down the pipe it was only trickling the other end at first.

In the end after a few doses of acid and running hot water through I managed to get it clear enough for the saniflo to now work.

I feel like this'll happen again so might offer my powerflush idea, maybe an hour with FX2 and an hour with DS3 (scale remover) or something