Joining steel pipes to plastic

[danijames]

Hello. I need to connect the two steel pipes on right here (hot/cold) to the two plastic pipes on left. The steel pipes run to the existing kitchen and are in use today. The plastic ones end just out of the photo and have been set into the floor to (hopefully) link to a new utility.

How do I put a T on the steel pipes? Many thanks

 

[Madrab]

Oh my, that won't be easy. You may end up having to transition the galvy to copper or plastic, tee from that and transition back. That won't be a very pretty solution either.

The norm for that would usually be cut the steel, thread the ends and then attach a dielectric coupler/nipple to transition to copper but that may not be possible given the orientation, alternative may be a plasson/philmac transition but they're really bulky.

 

[JackK]

Is galvanised steel used in central heating systems still supported in this country - I have a one pipe system and I am noticing that getting fittings is very heard. Heaven help when a pipe springs a leak !

 

[Madrab]

s galvanised steel used in central heating systems still supported in this country

Nope, not a standard at all, even then it's was more Stainless than galvy. In certain commercial/industrial settings then yes but that tends to much larger spec than domestic.

 

[scw24489]

To insert a tee in the steel pipework, cut a two to three inch section from the steel pipe, thread the ends, thread a tee onto one end of the pipe and a nipple into the other end of the tee, thread a union onto the nipple and the remaining main pipe run end, This will leave a female branch that you can insert a male iron/pushfit adaptor fitting.

Obviously the threaded joints will need making with appropriate potable compatible materials such as ptfe or sealant like loctite 577.
the length of pipe cutout is obviously critical and needs to match the tee, nipple & union fittings you obtain.
A flat face union cf cone seat, will be easier to join if the pipe has no longitudinal

flex

 

[scw24489]

@jack K

While steel barrel is being displaced by press fit in some applications , malleable iron fittings and pipe black or galv are still regularly specced and are readily available form any reputable merchant (wolseley, bss etc or your local chains), alternatively there are many online suppliers like BES. If you're looking in sheds then you'll be out of luck even in times gone by!

 

[JackK]

How hard is it to cut into steel and introduce a Tee with a threading machine? Most plumbers dont even know what a one pipe system is so I am not optimistic !

 

[scw24489]

Not difficult, hacksaw/sawzall/grinder & files, threader and some stillsons, needs a little experience to gauge the length to cut out. Your best bet is to find an old boy who was around back in the day when barrel was regularly fitted as gas carcass in domestic!
If you fancy a go yourself then a hand threader, not lecky if pipe is adjacent to wall.

The one pipe system is irrelevant to the teeing procedure but ,yes, the number of installers familiar with one pipe is diminishing as it is not current practice and hasn't been so for a generation or two. I don't suppose you'll find many mechanics who know where the electronic diagnostic socket is on a Moggy minor either

 

[danijames]

Just wanted to say thanks for all the helpful feedback on this, particularly to scw and madrab.
I cut the cold water pipe with an angle grinder and used plasson universal fittings at either cut end, and some mdpe tees and copper adaptors. That's all working well and we have cold water which is running the sink and dishwasher for Christmas.

The plasson fittings / mdpe doesn't appear to work for hot water so the hot water pipe will wait until can get someone into, or can get round to threading ends for the hot pipe.

 

[cross thread]

If your willing to pay you can hire a press gun and press fittings that will work .BES hire the gun and sell the fittings.