Discuss Green Verdigris on PRV in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net

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Hi,

I have a PRV located in a heated plant room that is between a pair of stop cocks. It was installed to keep pressure under 3 Bar a couple of years ago but I have noticed an area of verdigris on the piece from the main body to the gauge. I wondered if this might be sign of a leak / trouble or possibly just condensation that might occur when very cold mains water comes in through a warm plant room.

It's not wet to touch and no evidence of drips as there is in fact cardboard below so it would show up.

If it needs attention, I best get it replaced.

Thanks in advance.
 

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That’s normal just porous brass
 
Brass is mainly copper so it can behave like that, maybe it was a temporary drip, leak or a blob of dripping flux either way it looks secure. Clean it off with a scouring pad or wire wool and keep an eye on it if it really bothers you.
 
Brass is mainly copper so it can behave like that, maybe it was a temporary drip, leak or a blob of dripping flux either way it looks secure. Clean it off with a scouring pad or wire wool and keep an eye on it if it really bothers you.
Thanks… Cosmetically it’s no issue to me. I was concerned that it was a sign of the fitting rotting / corroding to a point where a leak maybe imminent. That’s clearly not the case so I will leave it be.
 
So is it water / condensation on the outside that has caused it? From what you’ve said it doesn’t pose a leak risk and I should stop being paranoid.

It’s water leaching through the brass
 
If the water in the pipe is from an unvented closed circuit (eg heating system) it should be fine, especially if there is inhibitor in it.
If from a fresh water supply being replenished from the mains (eg containing chlorine) there's a very slim chance there could ultimately be an issue.
The two most common mechanisms that cause faults in brass are stress cracking - where stresses in a casting introduced during manufacture cause cracks to open up (I suggest unlikely with these fittings) - and the other is "de-zincification" due to the chlorine in the water reacting with the zinc in the brass and causing voids to be 'eaten away' in the casting. Both symptomatic of poor manufacturing techniques.

I wouldn't worry that the fitting is suddenly going to disintegrate or leak majorly, but possibly worth keeping an eye long term!
 
If the water in the pipe is from an unvented closed circuit (eg heating system) it should be fine, especially if there is inhibitor in it.
If from a fresh water supply being replenished from the mains (eg containing chlorine) there's a very slim chance there could ultimately be an issue.
The two most common mechanisms that cause faults in brass are stress cracking - where stresses in a casting introduced during manufacture cause cracks to open up (I suggest unlikely with these fittings) - and the other is "de-zincification" due to the chlorine in the water reacting with the zinc in the brass and causing voids to be 'eaten away' in the casting. Both symptomatic of poor manufacturing techniques.

I wouldn't worry that the fitting is suddenly going to disintegrate or leak majorly, but possibly worth keeping an eye long term!
Thank you. It’s on the mains supply to the house. I had it put it when they were having spikes in pressure in our area so as to protect any potential issues internally. I could just get it taken out as it’s not required any longer. I guess it’s just another point of failure if left in place.

Good to know it’s unlikely to fail catastrophically.
 

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