Thread: Hot Water Pipes??

DrAndy,

Before you run off and buy copper pipe, take a look at a German product, its a pipe made up of a pvc inner aluminium center and pvc outer, you can find this in Kanyong (not sure of the spelling) and a Chinese copy in Home mart. I have just run copper for a hot and cold system in my new build, copper is time consuming to work with and running at the same price as this German plastic pipe. If you do use copper, protect it if it is in contact with cement

Originally Posted by DrAndy

thanks guys, copper it will be

I did search through the forum and noticed people complaining about using other fittings that made the copper corrode. Better stick to the same metal then!

how much is copper tubing, say 1/2 inch, and 3/4 inch, per metre?

Dr Andy,

If you are referring to two dissimilar pieces of metal at a connection .You need to get a dielectric fitting so that electrolysis does not occur, which will cause your pipes to corrode! And, use lead free solder on your joints. Also, remove as much of the flux off of the soldered joint afterwards. If your see a green trace the next day you still need to clean that joint some more. Otherwise the joint will corrode from the acid that has formed.

The Dude

thanks Guys for that. I will get you over to do the work FF

I have used copper before in the UK, without any problems. I suppose the high cost is due to the pipe being imported, but it sounds worthwhile. I shall make sure the fittings are the correct type.

I am not sure whether cement causes the pipes to corrode. If in a damp floor, maybe there is some acid, but prob OK in the walls?

Here I was going on about galvanic corrosion and forogot you want to emed the pipe in concrete.
I found this little ditty:
"The copper tube must be completely embedded in the concrete and adequate provision for thermal expansion should be provided where the tube enters/exits the concrete."
And then...
"According to the Portland Cement Association the interaction of copper with both dry and wet concrete should not cause a corrosion concern. However, copper should be protected when it comes in contact with concrete mixtures that contain components high in sulfur, such as cinders and fly-ash, which can create an acid that is highly corrosive to most metals including copper."

Many radiant heating systems use copper tube embedded in concrete floors & walls that have lasted for decades. There is quite a bit of information on the net about radiant heating using copper and other materials. Not much different to what you doing just an order of complexity and magnitude.

Why not try to devise method where the copper tube is not embedded but covered by trim? while most of what I've read indicates copper embedded properly in concrete shouldn't be a problem how reliable it the mix you get? or the guy installing it?

A drive around any city in Thailand will reveal any number of home or townhouses that used steel pipe embedded in concrete that not sport gaily colored decorations of PVC pipe mounted to the exterior and interior walls...

Originally Posted by friscofrankie

"The copper tube must be completely embedded in the concrete and adequate provision for thermal expansion should be provided where the tube enters/exits the concrete."

The normal way of doing it here is to isolate the copper tube with a foam tube, the same type that is used for aircons.
The wall outlet is fixed by concrete, and the copper tube can move little within the foam tube when it expands.
The foam tube does of course also prevent from thermal loss since the copper tube is not in direct contact with concrete, except at the outlets.

I've seen several methods and read several opinions the folks at Copper Development Association - www.copper.org - Info on copper and its alloys. have some good recommendations, but read enough, you'll find differing opinions. They recommend the wrap as you do when passing tube through a wall of floor (we used to use PVC conduit and expandable foam) but when embedding make no such recommendations. The opinion stated could be construed as recommending against it.

You can buy pipe that is wrapped in a plastic coating. If the quality of concrete is suspect I wouldn't trust any of the mechanically attached "protective" coatings.

Too many variables really, I do not like embedding anything in concrete that may eventually need attention and would try to plan accordingly. Conduit for electrical or any other utility that has to pass thru concrete always make me feel a bit more comfortable.

In the US where I worked for a concrete construction company (over twenty+ years ago) waste and fresh water PVC pipes were embedded, can't say I remember one instance where any metal pipes were. Hot water was always copper, BTW.

Even using proper solvent cement that does not give up it's grip in hi-heat situation I have seen PVC pipes collapse from over heated water. A solar water heater isn't likely to generate that much heat but again why risk it?

Like I said there is enough conflicting "expert opinion" out there to make a guy nervous. One could make an argument for or against the foam-wrap or no-wrap methods. Maybe a nice rubberized paint like Glyptal electrical coating (I use this on the insides of engines I rebuild) or an epoxy paint?? All this adds expense and complexity.

Avoid PVC, use copper, don't embed if at all possible.

Clear as mud, no?

Damn FF, you are one of the few that I have ever seen that believes in Glyptol in the crankcase, I am a firm believer in it.
Coat the insides with it and everything drains back and a lot less moisture in your lower end than plain cast iron.
A friend thought I was nuts when I coated the insides of the 350/350 I built for my 35 ford pickup I built a few years ago,, did it anyway tho..

Originally Posted by friscofrankie

You can buy pipe that is wrapped in a plastic coating. If the quality of concrete is suspect I wouldn't trust any of the mechanically attached "protective" coatings.

Well, I have seen builders down here covering the copper pipe with normal blue cold water conduit.
I guess it will be a bit of the same as the plastic wrapped pipe.

In the UK any house built with block will have the walls chased out and the copper pipes embedded in it (as well as the leccy cables). I think that's why DrA is sure he wants it like that, because it's what we're used to.

Originally Posted by lom

Well, I have seen builders down here covering the copper pipe with normal blue cold water conduit.
I guess it will be a bit of the same as the plastic wrapped pipe.

fuck of a lot better IMO

Could have over done it with the price of the Brazing set, I must contact her with the purse.
You will need wire wool to clean the copper joint, this was difficult for me, my wife and I have returned to Thailand having spent the last nine years in the UK, she used wire wool or a brillo pad many times to clean the grill or pans in the UK, do you think I could explain this is what I need to clean copper, in the end I found some in a hardware stall in a market aaaa foil not wire wool was the reply from the market trader.

When they did my aircons the guy used "silfos" silver solder with the special paste that is used with it, it is a flat stick thing and not a round wire type solder, I have always used it when putting in reefer systems in fish holds and reefer plants and have never had a bad joint and never had one fail, far superior to lead solder. But it does take more heat than you get with a propane torch.
But the silfos will flow where ever you have put the flux.

blimey

anyway, I shall use copper, and embed it in some conduit, and try to use the best solder

my plumber does not know about hot water, so he brought along his "friend". He quoted me 850baht a metre for installing the copper pipe. That was nice of him. Now I need a good plumber in CM! Maybe FF and me can do it together; he can talk about old times and I can do a bit of soldering.

and maybe Marmite was right, I like the way I do my plumbing in London

Originally Posted by DrAndy

Now I need a good plumber in CM!

Thailand does not have plumbers, only universal building workers..
Go and talk with an Aircon company , they have everything needed and have done this kind of job before.