Cast iron pipe repair

[Trix850]

Steel pipes to radiator valves (90 year old house) are very badly corroded. I want to replace the final section, joining to the old pipe which is in sound condition further back under the floor. What's the best way to do this?

 

[Madrab]

Malleable iron fittings.

You'll want adapters, possibly 3/4" to 22mm but you need to check the sizes and what the rad valve intel fittings are too as they aren't standard compression.

 

[Trix850]

Malleable iron fittings.

You'll want adapters, possibly 3/4" to 22mm but you need to check the sizes and what the rad valve intel fittings are too as they aren't standard compression.

Thanks madrab. It's marked "1/2" on an elbow further back, picture added. I could just replace with malleable iron/steel fittings then?

 

[Madrab]

Yes - I'd probably look to take that rusted vertical pipe out, the bottom elbow and the horizontal piece, then fit a 1/2" >15mm compression coupler into the elbow, then a piece of 15mm copper along, a soldered elbow and then a piece of 15mm copper up to the valve.

I'd also look to change the rad valve to a standard 15mm compression angled valve at the same time.