New boiler, pipes, dirty water in radiators

Leif

A month or two ago I had a new (combi) boiler installed, and the pipes replaced as the original ones were above ground, and I wanted them hidden in the screed floors. Recently I removed some radiators to paint the walls, and the water that came out was clear at first, then black and, towards the end of draining each radiator, sludgy. Is it normal for the water to be so dirty after replacing the boiler and pipes?

DVardysShadow

Perfectly normal. The balck sludge is iron oxide from the radiators, which you did not change. To prevent further formation, you should have your system treated with corrosion inhibitor.

Leif

DVardysShadow wrote: »

Perfectly normal. The balck sludge is iron oxide from the radiators, which you did not change. To prevent further formation, you should have your system treated with corrosion inhibitor.

Okay thanks. I was wondering if cleaning the radiators would have been a normal part of the boiler and pipe replacement, but evidently not. I suspect the plumbers added corrosion inhibitor, and I will add more when I put the radiators back on.

mikey72

There should have been a powerflush or chemical flush at the very least before commissioning the new boiler.

BuntyB

Hi, Similarly to you I had a new boiler installed but kept my rads. The plumbers put a bottle of system cleaner into the system which remained there for 2 weeks, all the time circulating and disovling the sludge. After 2 weeks they drained the whole system and re filled it, this time adding an inhibitor.

My advice to you is to either remove each radiator and flush it out with a garden hose or add a sludge remover cleaner to the system and leave it there for a week or two. After which simply drain the system and re fill with an inhibitor.

ziggyman99

mikey72 wrote: »

There should have been a powerflush or chemical flush at the very least before commissioning the new boiler.

I agree and that sludge WILL shorten the life of certain components in your boiler and could effect your warranty.
Sludge kills pumps, heat exchangers, divertor valves, expansion vessels, pressure sensors and gauges and radiator valves. It blocks pipes and radiators and costs up to 25% extra on your gas bill.

1984ReturnsForReal_2

BuntyB wrote: »

Hi, Similarly to you I had a new boiler installed but kept my rads. The plumbers put a bottle of system cleaner into the system which remained there for 2 weeks, all the time circulating and disovling the sludge. After 2 weeks they drained the whole system and re filled it, this time adding an inhibitor.

That is normally what they should do.

Leif

mikey72 wrote: »

There should have been a powerflush or chemical flush at the very least before commissioning the new boiler.

Thank you. Apologies for my ignorance/stupidity, but a chemical/power flush would have removed most of the black stuff?

1984ReturnsForReal_2

Leif wrote: »

Thank you. Apologies for my ignorance/stupidity, but a chemical/power flush would have removed most of the black stuff?

Powerflush will get some of it out while they are there.

Chemical flush means you pt the solution in & it suspends the much in the water & then you drain it out & refill.

But without replacing the rads it will never be 100% clear.

Leif

1984ReturnsForReal wrote: »

Powerflush will get some of it out while they are there.

Chemical flush means you pt the solution in & it suspends the much in the water & then you drain it out & refill.

But without replacing the rads it will never be 100% clear.

Thanks. The water went very black towards the end of the drain, perhaps a litre or two of dark black liquid, and some sludgy stuff.

Leif

According to the project manager "The dark brown water you are getting from the radiators when draining down is to be expected as mentioned previously we have filled with a water and chemical mix which will clean the rads."

In fact several pints from the last radiator were black. He said they had replaced almost all of the pipes (true) and emptied the radiators. Is his statement above correct?