Two questions about microbore fed rad on vented system not getting hot

[WaterTight]

FIRST QUESTION: IS THIS SET-UP OK AND IS THIS DIAGNOSIS PROCEEDURE OK?

Should mircobore be used in a vented heating system? Well this woman says on the phone she's got tanks in the loft and microbore on her heating. So presume that's what she's got. One rad doesn't get hot, the pipework to it does.

If microbore is acceptible on this type of system I'm guessing just like any other rad not getting hot check the usual first:

1) Bled / valves open
2) Turn down others to see if it's balancing
3) If none of above change TRV
4) Still no joy change lockshield
5) If still not working remove rad, flush it out and replace


SECOND QUESTION:

I've not worked with microbore before. Is there an easy way to tell if you're dealing with 8mm, 10mm or 12mm other than by eye? I thought of wrapping a bit string round the pipe to measure circumference. But what would the circumference be for 8mm, 10mm and 15mm pipe because those numbers refer to bore don't they?


Thanks..

 

[PlumbBobBob]

firstly check valves are open and working if there's a trv make sure the pin is moving. take the rad off and flush it through, while it's off open the valves to see if there's flow from both if there's not then most probably a blockage.

 

[stevetheplumber]

dont get to hung up with the fact its microbore same problems whatever size pipe to be honest its trv stuck most of the time especially at this time of year

 

[WaterTight]

thank you steve the plumber and steve the plumber. but just to clarify is it perfectly acceptible to use microbore on a vented system? i thought they were more for combi's and unvented. also anyone know the circumference of microbore pipes? i'm not convinced i'd know my 12 from my 10 or my 10 from my 8 simply by eye if i needed to get fittings.

 

[jncalderc]

You dont get 12mm Micro only 8 or 10. 8 is a rarity these days and is obv visibly narrower than 10mm
No prob using on a back boiler sytem

 

[tamz]

Microbore is fine on open systems. It was being used long before sealed systems and combis were common.
Treat it the same as any other pipe.
8mm is about the thickness of a pencil and 10mm a bit bigger. You will know looking at it but if not and you want to measure it then work out the circumference using πd
3.142 x 8 = 25.136
3.142 x 10 = 31.42

Btw with the rad heating at the valve only if it is a dual valve the insert spreader has fallen off.

 

[Best]

Use a calliper if you want to measure inside or outer sizes of anything accurately. 12 mm pipe did exist, but haven't seen it for years.

 

[jncalderc]

Measuring a pipe with a caliper? seriously? Without risking being rude as a tradesman you should know 8mm from 10mm or 15mm. You only get 8 in copper. 10 is available in copper uncoated, coated and in hep2o pipe, but you all know that anyway eh?

 

[marleyco]

Just measure across the pipe width. 12 does exist. Not seen it in a house, more commercial diesel pipe's to engines or generators. Crossling would be place to buy. Still tons of 8 mm pipe's out there, so get used to it, you'll soon know by looking

 

[PlumbBobBob]

it's all well and good but if you're inexperienced it can be hard to tell especially if you haven't got anything to compare it with.

 

[Best]

Measuring a pipe with a caliper? seriously? Without risking being rude as a tradesman you should know 8mm from 10mm or 15mm. You only get 8 in copper. 10 is available in copper uncoated, coated and in hep2o pipe, but you all know that anyway eh?

I know it seems ridiculus to use a calliper for standard size pipes, but just saying it's an accurate tool if someone needed it. To be honest, when working with 28mm pipes etc, sometimes I look at a 10mm pipe & think it is smaller. As Tamz said, 8mm is like a pencil & looks delicate compared to 10. Seen 12 mm in older council homes here.