Tim`s description works for me. I call it a heater by-pass. I know little to nothing of fluid dynamics but suspect the angle may well play a part in such calculations, given how much simpler it would be to manufacture the by-pass as a straight link..? Perhaps best to note the angle in relation to flow and return, or at least replace it in the same way it was removed, assuming it was fitted correctly in the first place..?
Yup a couple of "T" copper plumbing fittings would do the job to some degree and better than a leaking and corroded pipe, which the one on my +8 was... Had to clean it up a tad as Rutters had no stock in the recent past, but was seeking to have a batch made up in time.
I suspect if one was really stuck just joining the pipes straight through would keep you on the road, though best NOT to switch the heater isolation valve off as that would inhibit coolant circulation.... You may also need to bleed the system if you find that the heater does not warm up..?
