Plumbing in a second central heating system

[MickyP10]

As mentioned in a previous thread http://www.diynot.com/forums/viewtopic.php?t=204540 my central heating system is mysteriously losing pressure which, I believe, is probably water leaking under the floor somewhere. I feel this is likely because this happened 18 months or so ago and I had to rip up the hallway laminate and dig up the screed to find the leak. The property is five years old and I can only guess the pipes haven't been protected too well by the builder. It is a long bunglalow, so maybe it's moving too much? As explained, I cannot find any leaks above ground and rather than ripping up all the flooring in a heart-breaking, piecemeal fashion, I was wondering if it would make more sense to leave the old pipework and run fresh pipework to the rads, etc from above ground, ie through the loft. This is a five-bedroom bungalow. Does that sound a reasonable solution? If this is feasible, what's a (very) rough ballpark figure? I can clear all the loft insulation, channel walls, etc, or must I have the pipework showing everywhere (that was the wife asking that question...).

* Have checked AAVs, relief valve, all rad connections and the pressure vessel is holding it's charge, so I'm guessing it can't be leaking internally. Boiler's (Firebird oil burner) dry underneath, motorised valves are dry. Pressure drop is quite alarming when cold, but largely fine when hot, Currently just running around a leak sealer to see if I can slow things down. Timing isn't good!

Cheers in advance

 

[kevindgas]

look into the cost of thermal imaging the pipes first you may be able to find the leak that way.
ask your insurance company if they would pay for it, some will.

 

[MickyP10]

Ta for the reply. I could do that, but don't have much confidence that it wouldn't spring a leak somewhere else the next week, month or year.

Although it mostly leaks when cold, with the last leak I thought I was close as, walking around barefoot, I could feel a hot patch in the hallway. Removed laminate and dug up the screed and it was one of those swan-neck connections that I was feeling the heat from, as it was simply nearer the surface. Not sure if an insurance company willl pay out for above, rather than below, ground remedial work. Will investigate, of course.

 

[WDIK]

stick nasty cheap perfume in system water and you just need to follow your nose

 

[MickyP10]

Hi, I actually tried that last time, don't know if it was you who recommended it. Was so desperate! And I still couldn't find it. Maybe the perfume wasn't cheap enough?

Trouble with laminates is the membrane holds the water and damp beneath away from the flooring, so you're really none the wiser if if there's a massive gusher under there. And, as I said, if I got lucky, found and repaired the leak, that still means two holes in 18 months, so there's more likely to be on the cards.

 

[electronicsuk]

What you propose will be fine. If you do most of the legwork then I imagine you'd be looking at around £1000-£1500 for parts and labour, but then again, I'm not a plumber! It's lucky you're in a bungalow, as it avoids the nasty task of taking up large amounts of flooring and drilling/notching joists.

To be honest, you could quite easily repipe the water parts of the system as a DIY job if you have the time and are willing to learn.

Pipework can go in the walls, in the past I have used 15mm copper and sleeved it with 20mm flexible conduit before plastering over. If you'd prefer to use plastic pipe and pushfit fittings, you can already buy pre-made 'pipe-in-pipe' for such purposes.

 

[MickyP10]

Okay, ta. Better start getting some quotes in!