Can old redundant radiator pipes be used to feed water supply to new gas boiler ?

[Bladerunner]

Hello all. I'm new to this forum and need some advice about some concerns about a new gas boiler that I have had fitted by a gas safe engineer.

My old boiler was a heat only (with a copper tank) and has been replaced by a modern combi boiler. It just used two 22mm pipes to feed to the diverter valve and return

There were also two 15mm radiator pipes that ran close to the old boiler which fed to a radiator in the next room

The new combi boiler needed two new 15mm pipes to supply the cold water in and hot water out which the old boiler did not have ( not needed as previously hot water came from the copper tank )

The installer decided to use part of the old radiator 15mm pipes to feed the water supply to the new combi boiler because he could not be bothered to lay new copper pipes. So basically the new set up has approx 3m of old 15mm pipe feeding the hot water to the new boiler and another 3m of the same old central heating pipes to supply the hot water out making a total of 6m of old radiator pipe being used before the water comes out of the hot water taps.

I expressed my concern over this point to the installer but he said he would clean the pipes out but I don't believe these pipes can be cleaned out properly.
A lot black gunk and bits of solder came out of the taps when the installation was complete
I have kept some of this old copper pipe and the insides are coated with a hard baked black soot like coating.

When I run the hot water ( a week after the installation) every now and again I can see microscopic bits of this black soot in the basin when the hot water is running fast and hot after a few minutes. The water overall appears to be clear apart from a small amount of these fine grit like sediments. It not much but its still there all the same and it does not inspire me with confidence with regard to this installer. I think stuff could take months or even years to clean out properly

I know its not good practice to drink from the hot water taps but surely an installer should take precautions to prevent the hot water supply becoming potentially contaminated.

In addition since the water feed to the new combi boiler feeds from the drinking water supply I feel there maybe the possibility of contamination of the cold drinking water supply by backflow particularly if the the water is left standing for some time.

My gut instinct is to replace the 6m of copper pipe because I don't know how long it will take to clear out.

Any advice would be appreciated

Thanks in advance.

 

[Deleted member 120897]

I would say it’s a breach of water regulations and your installer should have been aware of this. Rather than you replacing them at your cost, ask the installer again (I know the answer will be no, but tell the installer that you’re unhappy and will seek advice from your local water undertaker). If his answer is “no”, then I would speak to your local water undertakers water regulations department and they can force him to rectify at his cost.

With regards to cleaning - I would say they would need disinfecting.

 

[SimonG]

I wouldn't do that with old heating pipes for two reasons.
1. The crap that comes out the pipes.
2. The heating pipes may have been soldered with lead solder which is not suitable for potable water.

 

[Bladerunner]

Thanks for the replies.

Just to make it clear the tiny amounts of fine sediments come out when the hot water tap is turned full on and the water is at a high temperature.

The cold drinking water supply does not go through these bodged old radiator pipes but the water supply to the new boiler tees off the drinking water supply then goes through 3m of this old radiator pipe before reaching the boiler.

 

[Deleted member 120897]

The cold drinking water supply does not go through these bodged old radiator pipes but the water supply to the new boiler tees off the drinking water supply then goes through 3m of this old radiator pipe before reaching the boiler.

This is the crucial part, especially when water regulations are concerned. It’s still contaminated then, because it’s part of the potable water circuit.

 

[Bladerunner]

Sorry to be ignorant but what exactly is a 'potable water circuit ' ?

Does this mean the drinking water at the cold taps could be contaminated by standing water or back flow because the cold pipe supplying the boiler ( through the old redundant radiator pipe ) tees off the drinking water supply ?

 

[Deleted member 120897]

Does this mean the drinking water at the cold taps could be contaminated by standing water or back flow because the cold pipe supplying the boiler ( through the old redundant radiator pipe ) tees off the drinking water supply ?

Basically yes.

Apologies, it’s me being a little ignorant assuming people know what’s I'm on about

 

[Bladerunner]

Basically yes.

Apologies, it’s me being a little ignorant assuming people know what’s I'm on about

That's what I was worried about. Just checked the hot water at the taps again and there are are 3 tiny black flakes about 1mm across which become powder when rubbed - I can only conclude its the same gunk on the insides of the old radiator pipes. Looks like they will need to be replaced.

Thanks for your reply. Very much appreciated

 

[Deleted member 120897]

That's what I was worried about. Just checked the hot water at the taps again and there are are 3 tiny black flakes about 1mm across which become powder when rubbed - I can only conclude its the same gunk on the insides of the old radiator pipes. Looks like they will need to be replaced.

Thanks for your reply. Very much appreciated

Not only that, the mesh filter if fitted will become blocked rather quickly, resulting in lack of hot water.

 

[ShaunCorbs]

I would never do it as it’s something you don’t mix eg heating sys and water mains