I'd like to see empirical evidence on the effects of plastic fitting inserts, especially a comparison between hep2o, which uses very thin stainless steel, Vs JG speedfit and others with those thicker plastic ones. I'm not convinced those stainless inserts have much effect at all.

Nice Tips, Guys!

Adam The reason that secondary return pipe can not be in plastic is because the pipe isnt tested or bench marked for that application If you need to do it in plastic you can use MLPC pipe but only one recommended for hot and cold and not.the basic underfloor one.

Hi Heat Geek, Firstly, I'm a huge fan of the channel! But, you do stand on a platform of being an industry expert and you've made some sweeping statements in this broadcast which I would challenge. You state that "plastic pipe is strongly advised against" because the effect on system efficiency by the use of plastic fittings inserts. Where's your data to back this up? I do understand where you're coming from, especially thinking about the JG inserts. But, as others have pointed out, the Hep2O inserts are super slim. I still can't find any JG data, But Hepworth DO publish data for their fittings. Unless they're lying or it's a misprint, their quoted equivalent pipe lengths for 28mm pipe are Elbow 1.0m Tee 1.5m. The copper equivalent, as published in the Yorkshire Copper Technical Guide, is exactly the same at 1.0m and 1.5m. You state that plastic pipe "harbours MUCH MORE bacteria". Again, where's your reference for this? Anecdotally, copper is well known for it's anti-bacterial properties, but what do you claim "much more" actually is? And what's the relevance of that anyway? We're not discussing a potable water system. We're talking about a closed loop system of limited water content that is likely treated as well. You state that MLC offers an "increased O2 barrier" compared to other "basic" plastic pipes. Which pipes are you comparing it to? Are you referring to pex type pipes? Would anybody not use a barrier type when installing a central heating system? Even Maincor themselves don't claim MCLP has a permeability advantage over other plastic barrier pipes. You state in another answer "Any disruption causes turbulance and resistance. The increased velocity increases that effect". That's a pretty bland coverall statement of any fluid flow. Why are we talking about any increase of velocity? We usually design systems around a flow rate of 0.5-2.0m/s. That's got nothing to do with the material used. We design pipe sizes to acheive our aim with whatever characteristics our material of choice has. I'll say again what I said elsewhere, I'm no plastic fanboy. I prefer copper almost all the time. But as a fellow geek and engineer, the arguments are far more nuanced and shades of grey than you portray here. If you are going to paint a black and white world, please at least quote some material sources for your arguments.

Interesting to hear about the different types of regulation, plus the impact with plastic pipe work fittings on flow rates. Thought you might have covered Planning Regulations too, or at least said they were out of scope of this video.

Pipe diameter is key, regardless of pipe construction. If you new build heating with heatpump 1 inch pipe minimum the the biggest longest radiators you can buy for the biggest wall in that room.

I await plastic pipe manufacturers to respond. Just we we though pipes were smaller bore for good, back to stage one again.

8mm and 10mm copper microbore a no go then?

I'm no heating engineer but I thought it's a riven that you shouldn't use plastic piping with heat pumps or even regular central heating As it stands, I'll hopefully be replacing all may copper pipes from 10mm to much bigger ones anyway

R.H.I. Put the responsibility every 7 years on to the homeowners you have to say you are still using it and no changes to the system and they really noise you up to sign to prove it works.Not bothered about cosy and warm AFFORDABLE HEAT.cowboy installers on a Free Grant.