Engine plumbing - 15mm copper pushfit or compression?

[Tradewinds]

I wan't to fit an isolation valve in to the existing 15mm copper engine take off pipe for my calorifier. This will enable me to disconnect the flexible silicon connecting pipe (which can be squeezed closed easily enough) without losing a pile of coolant engine side from the open copper pipe.

Is there any reason why I can't use a pushfit fitting such as this one sold by Screwfix?
http://www.screwfix.com/p/conex-cuprofit-isolating-valve-15mm/18814

Instead of one of these compression fittings?

I know there's a difference in price with the compression fitting being cheaper but it's the functionality in practice i'm concerned about.
Will the pushfit give a 100% reliable join in the application I will use it for (on a vibrating hot engine rather than 'static' plumbing pipe runs) or am I better sticking with the tried & tested compression fitting?

TIA

 

[AngusMcDoon]

Colleague of mine in a brand new house had a pushfit fitting let go and flooded his house causing much damage.
Never heard of a compression fitting failing like that if properly assembled.

 

[cryan]

Compression. Push fits will be worse affected by the vibrations.

 

[Tradewinds]

That's a quick thumbs-down .

Many thanks.

Compression it is.

 

[paul-essex]

most of your car and motorbike fuel lines are push fit now days

on the domestic fittings front watch out some are max temp of 65

 

[Tradewinds]

most of your car and motorbike fuel lines are push fit now days

on the domestic fittings front watch out some are max temp of 65

Yes, thanks for that, I was aware of the temperature restriction but thought (probably wrongly) that applied to the plastic pushfits not metal.

TBH Angus McD & Cryan have put me off the idea for this particular application - I'll stick with what I'm familiar

 

[David2452]

When I use copper pipe for marine heating installs, usually for discerning owners where the tube is exposed, I always use Tectite push fit copper fittings (Screwfix sell them), they have a better tolerance to vibration and movement than either soldered joints or compression fittings, not had a failure yet but have known both compression joints to fracture the tube and soldered joints to part on boats.
Edit to add, it is essential that the tube is properly cut with a tube cutter and free from burrs.

 

[sailorman]

Colleague of mine in a brand new house had a pushfit fitting let go and flooded his house causing much damage.
Never heard of a compression fitting failing like that if properly assembled.

I would venture to suggest the joint was poorly made & the pipe not inserted fully so that the s/s retainer gripped the pipe

 

[Tradewinds]

When I use copper pipe for marine heating installs, usually for discerning owners where the tube is exposed, I always use Tectite push fit copper fittings (Screwfix sell them), they have a better tolerance to vibration and movement than either soldered joints or compression fittings, not had a failure yet but have known both compression joints to fracture the tube and soldered joints to part on boats.
Edit to add, it is essential that the tube is properly cut with a tube cutter and free from burrs.

Oh dear.

Suddenly getting indecisive now .

Tube is cut properly.

What about working temperature? It's going to be 88°C 'ish.

 

[David2452]

BTW, Tectite fittings are rated to 95deg at 6 bar when used with copper tube and the 316 ss ones are rated at 114 degrees at 10 bar and carry a 30 year warranty, not cheap or demountable on the - side.