Scaled up Safety valve drain pipe

[fisheggs]

Hi All.

Ideal Istor HE260 which had loads of problems with pressure vessels and safety release valves which are now hopefully sorted.

I now have a problem with the safety valve drain pipe (copper) being scaled up and any release causes the boiler to wee. I have tried unblocking but unable to send rodding down it. I took it apart upto the 90 bend and found the pipe virtualyy blocked with limescale. I would ordinarily replace the pipe, but this pipe runs along the floor in a flat and tees into other pipework.

Is there something suitable to pour down this releif pipe to start breaking down the scale?

 

[migoplumber]

mild sulphuric acid, does the job well, watch your eyes. no smoking.

absolutely do not mix with bleach, and rinse pipe well afterwards with water.

good luck
shaun

 

[fisheggs]

Thanks Shaun.

How long would it take to work through in your opinion?

 

[migoplumber]

the stronger stuff ( that you can buy ( or send your 5yr ) on the shelves in the supermarket in spain costing 1 quid a litre "salfumant" ) works in 20 seconds!
irrelevant but interesting.

the weaker stuff 5% or so can take 20 mins, and you will use more.

shaun

 

[flat pack]

Hi it cheaper in carrefour malaga 77cents migo,
ive just use 5 ltrs to clean my pool
what a dogs cajones, super job.
you can try fernox ds40 red and white tub dilute in hot water and pour in pipe
wear protection hands face eyes etc
flush out at end

good luck flat pack

 

[bobpape]

What size is this drain pipe, if it is as I suspect 22mm you are going to have a problem
clearing it of limescale,
I am not saying it can not be done but if you are using acid for it to be effective you have to have at least a small through passage within the blockage that water can pass through,

If the pipe is blocked some distance downstream all the acid will do is desolve the
limescale upstream of the blockage and simply add to the blockage,

One way of doing it if you still have a through flow is to introduce the acid in small
amounts and flush with water repeatedly,

Sometimes with blocked small bore pipes it is cheaper to renew the pipe,

I would be concerned about the limescale collecting because it means that the cylinder is blowing off all of the time,

 

[flat pack]

if you keep getting calc build up install a lime fighter magnet or replace old one.
if you can put hose on the pipe and a funel you load up the acid water and watch it go down as it work its way along the pipe ,in time you get there

flat pack

 

[Bernie2]

I would agree with bobpage on that. I don't know the actual boiler, but if its got an expansion vessel fitted it sounds like a sealed system. How come its got so much lime in the water? Wasn't it treated? And if the blow off pipe is full of scale then its been leaking when hot. But I suppose you know that anyway and that is why you have been repairing it.

The acid is good stuff but highly dangerous and it explodes if water gets on it.

Err! when I was a bad and stupid lad on repair work, we used it to clean down urinals in office blocks and sometimes left a bit in the channel, then went and hid. The office lads would go for a pee and it would nearly blow their socks off.

Please try and learn from my mistakes. It was a highly stupid and dangerous thing to do. But it does highlight the dangers of the stuff.

Incidentally most industrial chemists will not sell it to you without a company reference. But I think Brick cleaner is the same stuff only weaker.