White crystals appearing on fittings?

[Donkmeister]

I've noticed that on a couple of fittings on my central heating system there are some white crystals forming. I've only spotted this at a few points, all close together, and all near the top of the system (only the F&E tank is higher).

They've appeared around a gate valve, an isolator valve and around the 3-port valve. On the gate valve, there's so many that a clump appears to have fallen off.

What are these, how do I cure them, and should I be worried? Is it just inhibitor coming out of a small leak in the compression fitting and drying back to crystals? Thanks for any help!

Gate valve

• Donkmeister
• 18 Oct 2010
• 1

See crystals round gate valve at the bottom

3-port valve

• Donkmeister
• 18 Oct 2010
• 1

More crystals appearing at 3-port valve

Isolation valve

• Donkmeister
• 18 Oct 2010
• 1

More crystals around an isolation valve

 

[kevplumb]

OMG thats galloping copper rot

the only answer is to rip the lot out and fit a combi

failing that it has had a weep at some time

personally if it's ok at the mo leave it alone

 

[andyinthepeaks]

You are possibly getting an electrical effect at the joints due to the combination of acidic or mineralised water combined with dissimilar metals in the compression joints.

You effectively get tiny "batteries" at the joints.

I'd try liberally sprinkling earth bonding across each affected joint, which ensures no potential across the joint. Make sue the pipes are properly earth bonded somewhere else, the pipes can get isolated for example, if you have any push fit plastic fittings dotted around.

Maybe you could also replace the fittings with DZR types, (Dezincification Resistant)

 

[kevplumb]

who makes a 3 port valve in gunmetal

 

[JohnD]

ignore the jokers

it's limescale deposits left by a slight leak after the water has evaporated.

perhaps the original plumber had left his spanners at home and did up the nuts with his fingers.

it might have sealed itself by now with scale in the gap.

if you want, if it is still leaking, take apart the joints, clean them, and remake properly. PTFE tape on the olives is very good for sealing compression joints.

 

[Donkmeister]

Phew, so it's not galloping copper rot?

I think we can confirm it is indeed scale. Now knowing it probably wasn't hideously corrosive stuff, I tried dissolving some in water and sure enough, totally insoluble. Which rules out any of the nasty chemicals that might find themselves in a heating system accidentally after cleaning etc. as they have to be soluble to get around the system.

Thanks all!

 

[dubdad]

hmm i cinertainly aint no plumber
but scale? and stalagmites take how long to form???

is your water hard or soft
i keep getting flashbacks to them old batteries ,remember when u forgot to change them and they leaked??

anyhow theres allways the 'lick-must' test

i dont zinc it looks like limescale

 

[JohnD]

limescale is what it is.

Maybe youi don't live in a hard water area and are not familiar with it. Do you get scale in your kettle?

 

[45yearsagasman]

Purely and simply slight water leaks from poorly made joints.As suggested previously remake these joints after part drain and clean all the crud off and use PTFE or a good paste to help the seal.Electrical effect "my a**e".

 

[Donkmeister]

Very hard water area - When I got my dishwasher you could programme the hardness and when I looked it up on my water supplier website the number was near the top end of the scale.

As well as cleaning off fittings and remaking joints, should I ask heating dude to add more inhibitor to the system when I get it serviced? Or would that offer no benefit?

 

[JohnD]

if you are remaking the joints, you will have to drain it, at least partially, unless it is sealed or you bung the F&E

when you have it apart you will get an idea of how much sediment is in the water and inside the pipes. It might need a chemical clean which is a cheap and easy DIY job.

Either way it doesn't hurt to add another bottle of inhibitor. With luck there will be a label somewhere saying what type was used lat time, or an empty bottle by the F&E. Again it is an easy and cheap DIY job. Sentinel X100 is about £15.