2 radiators blistered within days

[rbecking]

We moved into our house 5 years ago, according to paper work it had whole new central heating installed 2 years previous so 7 years old now. Last year the radiator in bathroom rusted at bottom and started leaking so I replaced it with a towel rail and while fitting it put a bottle of sentinel inhibitor in.

2 days ago I noticed the radiator in hallway had 3 blisters if I touched slightly could feel water behind the paint, so I turned that radiator off, today noticed the radiator in conservatory is now covered in these blisters on both sides, it wasn't like that couple of days ago! (see photos below)

http://tinyurl.com/cg7b6r8
http://tinyurl.com/bsveuar

What is happening are the radiators rusting from inside, is it just coincidence its happened to 2 with days? Waiting for British Gas to come tomorrow but I suspect they will say they don't cover them.

Am worried about the other radiators, will they all need replacing? How much are you talking for to have 7 radiators replaced?

 

[ianmcd]

You have a serious problem somewhere radiators do not blister like that within days, either you have a serious over heat problem or over pressurise problem, your rads look a lot older than 7 years old too .

 

[Agile]

Rads can pinhole within days whan an open vented system is pumping over!

Apart from the age we know nothing about your system!

 

[gas112]

Those blisters all appear to be at the spot welds, strange one . Would not say that is caused by contanimated water
Might be caused by an earth problem with system having stray current in it

 

[rbecking]

It's a combi boiler sealed system. Was all fitted about 7 years ago by the previous owner who was a builder/plumber, I know the boiler isn't decent make (Ferroli Modena).

I noticed last couple of months pressure has been dropping slightly not a lot but suspected a small leak somewhere, had to top off about once a month to get it just over 1 bar, when it got hot it was 2 bar, noticed now when it gets hot it is 2.5 bar.

Yes the blister are all on the weld 'holes' on radiator, all the other radiators are same type and checked them and they look fine, these 2 radiators that have blistered are closest to boiler if that makes a difference?

 

[ianmcd]

havent seen those round top rads for a lot longer than 7 years but dont think age of the rads is your problem , it is unusual for rads to blister like this really quickly, are you sure it was inhibitor that you poured in and not system cleaner ? the old sentinell Ferroquest was extremely aggressive but I would have expected this to have happened before now if that was the problem

 

[Whitespirit66]

Is it definitely water inside the bubbles? Can't believe a thin layer of paint would hold back the pressure if there were holes under these bubbles, when the system was on.

 

[rbecking]

havent seen those round top rads for a lot longer than 7 years but dont think age of the rads is your problem , it is unusual for rads to blister like this really quickly, are you sure it was inhibitor that you poured in and not system cleaner ? the old sentinell Ferroquest was extremely aggressive but I would have expected this to have happened before now if that was the problem

Sentinel X100 1 litre, still got the invoice here.

Maybe the radiators weren't new when he fitted them then? Plastic pipes around house ten copper up to boiler.

 

[rbecking]

Is it definitely water inside the bubbles? Can't believe a thin layer of paint would hold back the pressure if there were holes under these bubbles, when the system was on.

Yep turned the valves off to radiator and touched one and dribble of red/brown water came out

 

[HERTS P&D]

who was a builder/plumber

That's where the problem started.

Drain down, flush and new radiators.

Andy

 

[JohnD]

can you see any print on the plastic pipes? there is a grade that used to be used which allowed air to diffuse through.

 

[rbecking]

who was a builder/plumber

That's where the problem started.

Drain down, flush and new radiators.

Andy

How much we roughly talking to get a local plumber to do that with 7 new radiators?

 

[Whitespirit66]

Is it definitely water inside the bubbles? Can't believe a thin layer of paint would hold back the pressure if there were holes under these bubbles, when the system was on.

Yep turned the valves off to radiator and touched one and dribble of red/brown water came out

It's certainly a strange one. I still can't see how a few microns thickness of paint can hold back a pressure, up to 2.5 Bar from what you said. As a pressurised system, I would have expected a jet of water, rather than a small dribble from the one you touched.

Please let us know what the outcome was and if there actually are holes behind the blisters.

 

[HERTS P&D]

Measure the rads and match up the sizes with a screwfix catalogue.

Andy

 

[sooey]

Good point from johnd, you need to find out what plastic pipe he used, was it barrier pipe or not.