Corrosion on pipe connections.

[r.bartlett]

Chaps,

I'm in Tenerife looking after a few houses. They are only 3-4 years old and this is the second solar tank to fail due to severe corrosion on the collector connection.

Has anyone got any ideas why this should happen and both failed on this one connection after such a short time whereas the other connections seem unaffected?

Thanks for sensible advice.

 

[ShaunCorbs]

The stuff inside the pipes are very corrosive and by the looks of it as the valves off it’s just sitting there tbh looks like it’s needs a new system

 

[r.bartlett]

Thanks for the reply

they don't tend to use inhibitor here so it's just water to>from the solar panel

The valve(s) ware turned off to stop the leaking after the event

A new tank is being ordered monday but what we don't understand is why the bottom connection is clean and yet this one is rotted out (same as another villa)..?

 

[ShaunCorbs]

It’s the hottest connector on top

 

[Ben-gee]

Has the fluid got glycol in it?
It then gets over 100 deg c and you need ‘special’ fittings.

 

[r.bartlett]

Has the fluid got glycol in it?
It then gets over 100 deg c and you need ‘special’ fittings.

This has already been answered?

 

[r.bartlett]

It’s the hottest connector on top

Why would that make the 'hotter' one rot out if the bottom -which would only be around 10c cooler- show no signs of decay?

 

[ShaunCorbs]

40dc cooler

Top one would be around 80 bottom 40 ish also the higher the temp depending on how old the liquid in the system is it becomes very corrosive

 

[r.bartlett]

40dc cooler

Top one would be around 80 bottom 40 ish also the higher the temp depending on how old the liquid in the system is it becomes very corrosive

40c? If the hot water cylinder is sitting at 70c I cannot see how the water entering is over 110c+. to get anywhere near a 40c ?. Plus it's corroding from the outside not inside or it would pinhole leak before the outside corroded so badly?

 

[toucan]

40c? If the hot water cylinder is sitting at 70c I cannot see how the water entering is over 110c+. to get anywhere near a 40c ?. Plus it's corroding from the outside not inside or it would pinhole leak before the outside corroded so badly?

Perhaps I'm missing something but isn't this just melted insulation sticking to the pipework

 

[r.bartlett]

Perhaps I'm missing something but isn't this just melted insulation sticking to the pipework

no that's rust and rot.. compare the two top and bottom.. especially where the threaded section on the tank is.. that's where the leak is..

 

[gpbeck]

What’s the sodium content of the water?

 

[Chuck]

The first image seems to show a trail of corrosion running vertically down the white tank. Could it be a leak above the fittings is letting fluid run down and corrode the lower ones?

 

[r.bartlett]

What’s the sodium content of the water?

I have no idea but it's rotting from the outside in so it's not whatever is in the tank/pipes it's something else. the bottom connection is undamaged..

 

[r.bartlett]

The first image seems to show a trail of corrosion running vertically down the white tank. Could it be a leak above the fittings is letting fluid run down and corrode the lower ones?

the trail is from the corroded fitting down to the uncorroded one..

 

[king of pipes]

I would be contacting the manufactures of the solar cylinder for their input is there a sacrificial zinc/Aluminium anode installed ? In the unit ? if this has failed then it could be the cause,?.. kop

 

[Ric2013]

This has already been answered?

Not really. You said they don't tend to use inhibitor so you assumed it's just water. Glycol is a kind of antifreeze that also raises the boiling point so non-use of inhibitor isn't a reason to assume non-use of glycol.