Plumbing stuff.

[difflock]

Apologies for not beiing Arb related but ah dinny indulge on any other forums.

Anyway, I was gutting out a host of crazy convoluted plumbing relating to a monsterous 18kW Charnwood stove that is being removed as a condition of getting a grant aided gas boiler installed, tracing pipes and labelling them for the plumber.

I had had to replace the totally siezed stopcock on the 15 mm incoming mains.

Ho hum, no worries.

Plus stop-ended the 2 No. 28mm pipes coming in(and out!) from the old oil boiler located in the garage.

Ho hum, no worries.

It was not until I went to re-route a 22mm pipe that I realized it was actually 3/4". Which would probably, in hindsight of course, tally with the 1970's build.

So old 1/2" is indestinguishable from 15mm and old 1" is indestinguishable from 28mm.

But 3/4" is nearer 21mm than 22mm.

Why

Why

Why  .  .  .

 

 

 

Edited May 7, 2021 by difflock

[David Lawrence 88]

Grant aided gas stove 

 

is that because it is replacing a stove burning coal anthracite type fuel ?

 

 

 

[difflock]

Gas boiler btw.

No idea, it is for the daughter who done the paperwork, for her house, it was presumably a multifuel.

She is in the notion of a gas stove though I favour a smaller woodstove for room heat only.

Cheers

m

Edited May 7, 2021 by difflock

[carlos]

i recently did all the plumbing on our renovation and all the sizes seemed very mixed up, the plastic came in both metric and imperial but the copper only came in imperial, it wrecked my head on a good few occasions!!!

[openspaceman]

1 hour ago, difflock said:

So old 1/2" is indestinguishable from 15mm and old 1" is indestinguishable from 28mm.

But 3/4" is nearer 21mm than 22mm.

Why

it's a fudge

 

IIRC but somewhat along these lines:

 

Old 1/2" was internal diameter but with a wall thickness of 1.15mm became metric 15mm O.D.

3/4" I.D. has a slightly larger wall thickness around 1.2mm and becomes 21.45mm O.D.

1" I.D. with a wall thickness of 1.25mm becomes 27.9mm O.D.

 

The difference is all taken up with the olives so to connect an imperial pipe to a metric fitting you need the imperial olive

[Baldbloke]

it's a fudge

 

IIRC but somewhat along these lines:

 

Old 1/2" was internal diameter but with a wall thickness of 1.15mm became metric 15mm O.D.

3/4" I.D. has a slightly larger wall thickness around 1.2mm and becomes 21.45mm O.D.

1" I.D. with a wall thickness of 1.25mm becomes 27.9mm O.D.

 

The difference is all taken up with the olives so to connect an imperial pipe to a metric fitting you need the imperial olive

 

The best explanation over pipe wall thickness and corresponding ID/OD I’ve seen.

[difflock]

I had been aware that the Imperial system was based on internal bore size, and the newer-fangled metric system was OD based. But that very clear explanation was spot-on.

Anyway, do the push-fit fittings sealing with "O" rings be intended to be a "one size fits all" solution and the 22mm fitting will work on 3/4 pipe, or is that chancy.

I ask because the previous occupant who installed the Charnwood has "Teed" in with modern push fit shit on the 3/4 pipe beneath the floor.

They were apparently not leaking, but are unsettlingly slack on the 3/4 pipe.

I was in a notion of replacing them with capillary or compression fittings, ***to be sure to be sure.

Cheers,

Marcus,

***Edit,

To say to be sure to use imperial compression rings per your sage advice OSM.

Thanks

 

 

 

 

 

 

 

 

 

 

 

 

Edited May 8, 2021 by difflock

[openspaceman]

1 hour ago, difflock said:

They were apparently not leaking, but are unsettlingly slack on the 3/4 pipe.

I was in a notion of replacing them with capillary or compression fittings, to be sure to be sure.

My second try at posting a reply; I have used Hep20 with push fits for DHW but never joining old imperial. I would use a push fit to compression adapter and a 3/4" imperial olive, chiefly because I am poor at soldering wet fittings

[spudulike]

I had the same in my previous house, 3/4" and only had 22mm pipe. The normal fix is something called Plumbers Mait and a 3/4" compression fitting and use lots of force to do it up......sealed up in my case and terminated in a fully metric new bathroom!!

Plumbing is OK, the biggest issue is getting to pipes and fittings in restricted spaces.

[Deafhead]

15 hours ago, spudulike said:

I had the same in my previous house, 3/4" and only had 22mm pipe. The normal fix is something called Plumbers Mait and a 3/4" compression fitting and use lots of force to do it up......sealed up in my case and terminated in a fully metric new bathroom!!

Plumbing is OK, the biggest issue is getting to pipes and fittings in restricted spaces.

Why not use a 3/4 x 22mm coupling.