Central heating pipes and pump corrosion

[rallen]

I had to replace the central heating pump yesterday evening because the old one stopped working - I think it started leaking and shorted the electricals. As it was so calcified, I just bought a new one plus the top and bottom connection bits.

I have attached some pictures of the stuff that is "growing" on those pipes. I presume there are small, tiny leaks around those compression joints and then that white stuff gets formed, but also there is this most strange blue colour as well as the green.

Can anyone tell me what this is? I have a water softener in the house so it may be related to the salt?

 

[Best]

Copper & brass will become a mess very quickly when there are slight leaks. Not going to attempt to answer what the corrosion process is, but it will happen on any leak, if from hot & cold pipes, or from a central heating system which will have it's own water & inhibitor. Once the air can get at it, they basically " rust "
Looks like those are fairly bad leaks. The brass joints should not leak at all, if done properly - not over or under tightened & a slight lick of paste should really be used on olive to provide a fine seal. All gate valves etc, should be checked that the packing nut is tight so no weeps. The corrosion destroys fittings & pipe & could cause them to rot through.

 

[rallen]

Sometimes I cannot get proper seals on some compression joints even with paste. And as the system needs to be drained to make any repairs you do not really know how good/bad the joint is until it is too late... Project for next weekend maybe - drain system and replace 3-4 joints.

 

[jtsplumbing]

Cut it all out and replace, are you cleaning the system and putting inhibitor back ??

 

[WHPES]

Use a few turns of PTFE round an olive if you are habing trouble getting a compression joint watertight.

The debris is limescale. WHat has probably happened is that over time the water has leaked out with the inhibitor and been replaced with fresh water (without inhibitor) from the F&E tank. The fresh water has caused the corrosion.

Clean off and fix all the leaking joints (with the white deposits) and charge with inhibitor.

 

[rallen]

Over the past 12 years I have changed bits and pieces of this system and it has had just fresh water (softened water most likely). There are no added chemicals. What does the "inhibitor" do? Prevents limescale from forming?

 

[PlumbBobBob]

no it prevents radiators from rusting from the inside and protects boilers as well. main reason why you have so much corrosion on your pipework.

 

[Best]

Sometimes I cannot get proper seals on some compression joints even with paste. And as the system needs to be drained to make any repairs you do not really know how good/bad the joint is until it is too late... Project for next weekend maybe - drain system and replace 3-4 joints.

You shouldn't have any leaks - even very slight with compression joints if done right & paste also used. Don't over tighten the nuts. Some of the olives that come with valves etc, are rubbish - some are not tapered much. Can be better to not use them. Decent quality olives, brass or copper will seal on an undamaged copper pipe for sure.
Use paste, - I do, & have no leaks, weeps, ever! Just got to be fussy with every joint.

 

[rallen]

Since it has been running without inhibitor for 10+ years, is there evidence of gunk or other stuff forming inside the system that I can perhaps look out for? The water tank at the top looks clean, and when I drain it the water is slightly discoloured (I think it was a bit orangey as in rusty). So is it worth trying to drain all radiators around the house? And even if I drain them does this remove anything that might have accumulated at their bottoms?

 

[jtsplumbing]

Think you need to give it a good clean, add Fernox F5 leave in for a week , but keep useing system, the hotter it gets the better the cleaner works, when done drain with system hot, flush then add Fernox F1, if you have got one , use rubber mellett along bottom of rads, this shakes up rubbish in bottom of radiators.

 

[WHPES]

If you don't do as the previous poster said, your new pump will just fail quickly. A long time without inhibitor will almost certainly mean a heavily corroded and fouled system.

 

[rallen]

I have added a bottle of Sentinel X400 - it says to leave for a few weeks and then flush. I looked closely with a strong light, and those compression joints are leaking ever so slightly, and that is the cause for that external limescale that has built up. When I will get round to flushing the system, I will at the same time replace those joints.

As an aside, the X400 is a dangerous chemical (says on the box), so I am wondering what are the health risks of it finding its way into the hot water cylinder and then people wash, brush their teeth etc I would also think it slowly evaporating through radiators bleed valves etc, and then you breathe it ?

 

[PlumbBobBob]

it would only get into the hot water system if there is a split or holes in the coil in the cylinder. as for evaporating through rad bleed valves, don't see that happening and you would have to be right on top of the rad and inhale a large amount to do any harm. besides the x400 will have been diluted by about 100 to 1.

 

[WHPES]

x400 is mildly corrosive but not as corrosive as the drain unblocker or kettle descaler you buy at the hardware store. Do not leave in the system for longer than it says in the instructions!

If you undo all the compression joints that are leaking, clean off and simply wrap a few turns of PTFE tape round the olives then re-tighten its usually all that's needed.

 

[rallen]

OK, weekend project to flush the system and replace leaking joints.