Leaking radiators and boiler

[Cartboy52]

Help!

Over the last couple of weeks, I've had 2 radiators develop pin hole leaks. I've just discovered that the back boiler is now leaking (wet carpet under the fire).

The boiler is a glow-worm and is only 4 years old.

The heating system uses a header tank in the loft and cylinder in the airing cupboard. I've previously added rust inhibitor after altering some pipe work / draining and refilling the system etc.

Is it possible to have too much rust inhibitor in the system?
Could different brands cause a reaction? It had Fernox then Wickes own.

Is there some other problem causing the rusting?????

Thanks

 

[John506]

Mixing will not have taken place as you have drained down and filled back up, you can put too much inhibitor in but I think you would need a lot (many many bottles) to class it as too much.

How was the water when you drained down?

If it was black then the corrosion will have eaten away causing a small hole but not yet gone all the way through, then you fill back up but were the corrosion had affected it was too weak, and was inevitable that it would finally give.

 

[Cartboy52]

I haven't drained the entire system. I usually turn off the rads before draining down, so they will remain full.

The water usually ran fairly clear, although was was sludge in the bottom of a couple of rads.

 

[John506]

Ideally the water should run clean throughout the whole system, do a test, if you have any drain offs on any rad valves, drain off enough water to fill a jam jar, if you can't see the bottom of the jar when it is full, it needs a chemical flush at least. (if you don't have a drain off, use the bleed vent but watch you don't get sludge dripping down the rad onto your floor)

 

[Cartboy52]

I've had a chap round today who says my heat exchanger has rusted through.

Is this normal for a 5 year old boiler?

 

[yerino]

what inhibitor did you put in?

 

[Mark Br]

Check your F&E tank. Is there any sign that the system is pumping over?

 

[twgas]

I haven't drained the entire system. I usually turn off the rads before draining down, so they will remain full.

The water usually ran fairly clear, although was was sludge in the bottom of a couple of rads.

How do you know there was sludge in rads if you turn rads off and dont drain them?

 

[Cartboy52]

I've put in Fernox, followed by 2 lots of Wickes own stuff.

The system was overpumping, as the header was very full and lots of steam coming out the header (I delt with this a few weeks ago).

I know there was sludge, as I've gradually been changing radiators for newer ones as I've been decorating. I've also moved some of the pipe runs. When doing this, I've been turning off the rads that I've not been working on.

 

[twgas]

pumping over+hot f&e+sludge=pinholes in steel/iron+blocked pipes, (copper and plastic).
System in most likely piped up wrongly.

 

[Mark Br]

I delt with this a few weeks ago

You don't say how you dealt with it!

I would hazard a guess that the problem you now have with the rads and the back boiler is as a result of the system pumping over (very corrosive) for sometime.

You can replace the HE, etc, but unless you are sure the problem is sorted you will be replacing it again in 4 years too.

 

[Cartboy52]

The ball valve in the header tank wasn't shutting off, resulting in the overflow dripping. When I want into the loft, it was clear that there was hot water in the header from the steam coming off it. Also, the rafters above were damp and had white mold type stuff on them, so it may have been steaming for some time. The roof is slate with no felt.

Anyhow, I asked on here if a hot header is normal, and I was told that it was overpumping as a result of ther being too much water in the header.

I fitted a new ball valve and reduced the amount of water in the header to just a couple of inches.

However, as pointed out, it may be the way the system has been installed which is the problem. I'm no expert.

We are not having the boiler repaired, as the heat exchanger alone is £230+, never mind labour costs.

We are going to have a new combi and get rid of the tank and cylinder. When you mention the system may be poorly installed, is this with regards to the piping around the cylinder / airing cupboard area, or the pipe runs to the radiators? The piping in the airing cupboard has always baffled me!

 

[twgas]

Usually the airing cupboard pipework is wrong, but if your having a combi installed dont worry about it.