Old water heater? Pipe identification

[conny]

If any of the pipes are hot or cold (not heating) then they should be capped off at the source. Dead legs on pipework should be avoided.

Can be a breeding ground for legionella unless flushed on a regular basis.

 

[conny]

I'm not going to chase pipework around the house as I've no idea where source is? What's the issue with dead legs?

Surely what I'm doing now is better than was originally done?

See my reply above. There is a danger of legionella bugs breeding. Water temps should ideally be below 20C or above 60C to prevent it but so long as above 50C then they are seriously inhibited from developing. Mixed water for bathing/showering should be at least 41C whilst in use. All temperatures need to be obtained within 2 minutes of running the taps.

 

[denso13]

What's the issue with dead legs?

As mentioned legionella, which can cause death. It's up to you whether you do things properly or not.

 

[Louis.]

I'm confused.

There's 3 pipes uncapped which I'm cutting below the floor and capping. These don't appear to be linked to the water supply as obviously nothing is coming out of them.

The third pipe, which is capped, i'm unsure if it's gas, rising mains or just empty but I'll be getting a plumber in to resolve.

What am I doing wrong? I presume the plumber will trace it back if needed?

 

[Harry Bloomfield]

I'm not going to chase pipework around the house as I've no idea where source is? What's the issue with dead legs?

Dead legs of pipe - sections of pipework connected and containing water, but because they are a cul-de-sac with no through flow, are a perfect breeding ground for Legionella, which is quite deadly.

 

[Louis.]

Not once have I been talking about not tracing pipes that are capped

 

[denso13]

Not once have I been talking about not tracing pipes that are capped

Apologies if I misunderstood. Make sure the plumber leaves no dead legs on hot/cold pipework.

I'm not going to chase pipework around the house as I've no idea where source is?

 

[Louis.]

Apologies if I misunderstood. Make sure the plumber leaves no dead legs on hot/cold pipework.

I was talking about the uncapped.

My worry is that the capped one is mains water and I've been at risk. Surely the people removing the tank and fitting the combi shouldn't have left it like this?

 

[Harry Bloomfield]

I was talking about the uncapped.

My worry is that the capped one is mains water and I've been at risk. Surely the people removing the tank and fitting the combi shouldn't have left it like this?

No, they certainly should not have left live dead legs of pipes in place. No problem with leaving disconnected pipes in place, at all.

 

[Louis.]

Say it was a rising mains, and this was an old water heater. How would it work when it came to fitting a new combi?

What old and new connections would be used?

 

[Hugh Jaleak]

Say it was a rising mains, and this was an old water heater. How would it work when it came to fitting a new combi?

What old and new connections would be used?

Combi takes water from the cold mains and heats it on demand. Old 'conventional' systems usually had a cold water storage cistern, feeding a hot water cylinder. The pipework you've got left over may well be the cold mains supply to the loft cistern that fed the cylinder (and possibly a Feed and Expansion Cistern for the Central heating), a 22mm feed from the hot water cylinder to the hot taps. Then 2x 15mm central heating pipes, flow and return feeding either the cylinder or radiators.

Lazy Engineers or those doing a cheap job, will site the Combi where required and just tap into the existing pipework at a convenient point, leaving anything too difficult to remove in situ, and capping off as required. If it is cold mains supply that you've got capped, it should have been traced back to source and capped there when the Combi was fitted.

 

[Harry Bloomfield]

Then 2x 15mm central heating pipes, flow and return feeding either the cylinder or radiators.

More likely 2x 22mm for the main runs and to the cylinder.

 

[Louis.]

More likely 2x 22mm for the main runs and to the cylinder.

There aren't 2 x 22mms

 

[Louis.]

Combi takes water from the cold mains and heats it on demand. Old 'conventional' systems usually had a cold water storage cistern, feeding a hot water cylinder. The pipework you've got left over may well be the cold mains supply to the loft cistern that fed the cylinder (and possibly a Feed and Expansion Cistern for the Central heating), a 22mm feed from the hot water cylinder to the hot taps. Then 2x 15mm central heating pipes, flow and return feeding either the cylinder or radiators.

Lazy Engineers or those doing a cheap job, will site the Combi where required and just tap into the existing pipework at a convenient point, leaving anything too difficult to remove in situ, and capping off as required. If it is cold mains supply that you've got capped, it should have been traced back to source and capped there when the Combi was fitted.

Thanks for that! We have only recently purchased this property and boiler was already fitted.

I'll get a plumber in to service the boiler and at the same time look at sorting out the capped pipework.

Hopefully it's been terminated properly but just capped on one end whilst working.

We live in hope..

 

[Louis.]

Following on from this, I've scanned the pipe with an ultrasonic transducer and there's water inside but not all the way through to the end.

If it was at mains pressure I'd expect it to be under pressure and completely full? Or is it likely that its just an air bubble at the end?

Definitely not gas though.