microbore

[Stephen]

Hello,

What is the group's opinion about microbore? I haven't used it before but heard it was good for threading between joists, like PEX and PB pipe. But I've also read criticism it will block with sludge. Is this

8mm only or is 10mm susceptible too? Surely that's not a problem of the pipe but a problem with the system though, if there's that much sludge?

I was going to run 15mm pipe to the radiator but switch to 10 mm to run behind the skirting board for the last metre. Can you see any problems with this? By using just a short length would that avoid any problems?

Is there such a thing as microbore lagging? I haven't seen any at any plumbers' merchants.

Thanks, Stephen.

[mark.hannah]

Hi Stephen,

I have 8mm microbore running under the floors - and connecting to 15mm chrome plated copper "tails" just below the radiator - so i don't think you should have any problem with this.

Mark.

[NOSPAMnet]

I have that on one rad in the bathroom and propose to do same either in chrome or copper when I move /change a couple of rads in the LR

[Peter Parry]

I did late parents in laws house many moons ago using two 15mm long pipes under the landing and downstairs floor which had enough room underneath to do it all from below) as an extended manifold and taking off 10mm feeds at intervals to feed the radiators. The longest 10mm feeds were about 15ft. It worked for 20 years at least without any problems at all.

Air conditioning companies use it. eg

[Peter Andrews]

I've had a microbore system for 27 years without any problem, and a Potterton Neatheat (18 years) that has just required one replacement PCB in that time. My total service/repair costs in that time have been under £100. (Saying all this was probably a mistake but... :-))

Peter

[Jonathan Pearson]

Its okay, but most people prefer 15mm not because of the sludge / flow, but that its not very robust under general household conditions (eg kids hitting it/ hovering around it), thus although it was used on new builds between

5-20 yrs ago, most have gone back to 15mm using copper or plastic

Jon

[Lobster]

I thought it's main use was specifically *not* on new builds, ie for retrofitting CH in older properties with minimal disturbance?

Though either way I'm sure you right that the advent of plastic pipework will have affected the popularity of microbore given that it has many of the advantages of the latter.

David

[NOSPAMnet]

Kids hovering I'd imagine would be a problem :-)

[Arthur2]

What did the installation it cost you 27 years ago? Perhaps a hundred quid? And then perhaps the £100 it has cost you since installation occurred 26 and half years ago when the microbore disintegrated and ruined all your carpets and furniture...Hmmm?!!!??... Peter, I think you should provide evidence that you are not a very horrid person who wishes great trouble and expense for Stephen.

Come On!

Arthur

[Ed Sirett]

There is no problem with microbore provided that it is used and installed correctly.

However why specifically do you need to do this? Modern plastic pipe will cover the benefits of microbore for out of site work.

[Stephen]

Thanks for the replies. I agree that flexible plastic pipe shares the advantages of microbore: specifically running coils through holes in joists.

As it happens I intend to do most of the pipe work in 15mm, it's just that I'd like to run the last metre (or so) to the radiator behind the skirting board and for this, I thought it might be easier to hide 10mm pipe behind a skirting board than 15mm. I suppose 10mm plastic pipe must be available, but I haven't seen it whereas 10mm copper seems quite common.

I am unsure about using microbore with compression fittings. Is it similar to plastic in that you have to use inserts, as you do with PEX and Pb pipe? If so, why can't I see any? I looked at the usual suspects' web sites and no-one seems to sell 10mm inserts. The only thing I have found is Screwfix part 61867 "Conex Cuprofit Pipe Insert

10mm" which is sold in their pushfit section. Can this be used with other fittings, such as compression too?

Is there a cheaper make/store?

Thanks. Stephen.

PS Where do the similarities with plastic pipe end? Can I cut microbore with a hacksaw ;)

[Lobster]

No, you just use olives exactly as with 15mm or 22mm tube. Or (preferably) solder the joints, again similarly to 15/22mm.

You do have to be ultra-careful with microbore, in that it's very easy to deform the cut end compared with larger tube, such that it will leak at joints. Personally I use one of these for cutting microbore - works very well:

David

[Stephen]

Thanks for the help. I mistakenly thought I needed inserts for compression fittings but it's reassuring to know that I do not. No wonder I couldn't find anyone selling any!

I was joking about the hacksaw. I haven't been here long but have figured there's a joke about Dr drivel sawing pex pipe.

Thanks, Stephen.

[Doctor Drivel]

Yes.

You can saw plastic as long as the cut is square and trimmed off with no burrs by razor knife. But is takes time. The amateurs look at the maker catalogue and see an expensive pipe snippers and think that is the only way to cut a pipe. The plastic pipe snippers leave a sharp point, and this cuts the O rings of the fittings. So best use a cutter like the new Monument plastic pipe cutter, which is designed to not leave sharp bits. It looks like and is used like a pipe slice cutter.