Ready to hire?
Post your job in minutes, browse real reviews and choose who to speak to.Post a jobNeed some tips or advice?
Ask a questionPlumbing
Radiator flow/return pipe into inlet/outlet valves
Peter Reid 12/01/2026 - 8.44 AM
Hi. I am looking to replace a T22 with a T33 radiator. However the existing pipes around around 75mm from the wall, with the rad requiring 86mm. The pipes are 15mm copper with a soldered joint under the floor boards. Is it going to be an issue to have the flow and return pipe off centre at the inlet/outlet valve by 11mm, as in, will that place too much stress on the pipe and soldered right angle joint?
Are you a tradesperson and able to answer this question?
5 Answers
Wizardgas
No reviews yet
Copper can be flexed but it depends how long the pipe is between the existing valve and the soldered joint under the floorboard. Unfortunately you wont know until you uncouple the valve completely from the rad and you’re able to flex it forward.
Answered12 January 2026
1
Pressure Force SW
No reviews yet
An 11 mm offset is generally not advisable to accommodate by forcing the pipework, especially with 15 mm copper and a soldered joint under the floor. Doing so can place ongoing stress on the joint and increase the risk of leaks over time.
The correct approach would be to adjust the pipe position (or use appropriate offset valves/adaptors) so the radiator connections align naturally. A heating engineer/plumber can do this relatively easily and it will ensure a safe, long-term installation.
Answered12 January 2026
1
Anonymous user
You want all pipes going in to fittings Square and flush. With pasted compression joins, would advise against stressing the pipe or valve with off center entry. Use benders to offset the copper however you will see that off set.
Answered12 January 2026
1
David D.T.M Builders
Rating: 5 out of 5
Yes it can be an issue, and it’s not good practice to rely on forcing the pipe/valve over by 11 mm — especially with 15 mm copper and a soldered elbow under the floor.
The best way - Lift the boar cut back the pipe, Add a new elbow or short offset to bring it out to 86 mm
Re-solder or use a compression fitting then it’s no stress and long - term safe.
Answered12 January 2026
1