Plumbing question - galv to copper

[El Greyo]

Hello

We are trying to change our taps on the bath and have found that the stem of any new taps we've looked at are shorter than the ones we are trying to replace. So that means that we have to replace some of the pipework which has lead connected to galvanised steel. So I'd like to take out the lead and replace it with copper and then join it to the galv steel (Well I'd like to remove all the galv but that will be a large job and involve taking down the kitchen ceiling so not appealing at the moment).

So I've researched joining galv steel to copper and am aware of the problems for corrosion of joining copper to steel and that the best joint would be a dielectric coupling. But these seem to be not widely available and there are several joints between copper and steel amongst the plumbing anyway (which look like they are just brass). So I was wondering a) how crucial a dielectric coupling is and b) whether there is another way of joining rather that would be suitable. What do plumbers normally use?

Thanks

 

[88v8]

When joining to iron pipe, whether galvanised or not, I've used copper or brass, depending on the fitting manufacturer. I prefer Yorkshire taper, which tends to be copper.
I think any corrosion issues in a domestic installation are likely to be rather theoretical. As you say, your old taps will be brass.
Also, afaik there is no problem with retaining iron pipes, so long as they are not furred.

If fitting new taps with traditional washers, beware those that have no squares on the spindle, they are inclined to rotate in the basin. And if you buy cartridge taps, buy a spare pair of cartridges as there is nothing that can be done to repair them when they start to leak except fit a new cartridge... if still available.

Ivor

 

[robgil]

Because its galv you need a universal transition coupling.

Ask at your local plumbing shop , tell them what you need it for.

 

[El Greyo]

OK, thanks very much. I suspect if I use a universal transition, it'll be the only joint between copper and galv in the house that is right.

 

[robgil]

Keep in mind that the O/D of galv pipe will be greater than the O/D of the same pipe without being galvanized, thats why you need to tell the plumbers merchants what it is for, i've been caught out in the past with this.

 

[Peter D]

As you have already discovered, new taps have shorter pipe tails!

To save the faff of replacing your pipe work, there is a simple tap extender made that will screw onto your new taps and make them the same length as your old taps. Available at all good plumbing shops (including mine!).
Regards

 

[El Greyo]

As you have already discovered, new taps have shorter pipe tails!

To save the faff of replacing your pipe work, there is a simple tap extender made that will screw onto your new taps and make them the same length as your old taps. Available at all good plumbing shops (including mine!).
Regards

Thanks Peter - that looks like the least faff option by far.