compression fittings vs rubber pipe?

[paperhouselad]

Merry christmas all and a happy new year.
Recently fitted a propex compact under the rear seat, this involved using 8mm copper pipe, with 90 deg bends tee pcs etc, to save a getting plpe bender, did this as recommended to service the propex with gas, via copper plpe.
Have got small leaks though even after a few re tightens, going to revert to plan A with gas flexlble hose, jubilee clips etc with one piece of copper pipe with a tap to isolate the propex going into the heater. Anyone else struggle with leaks on small pipe fittings, thes were clipped back with no movement.I know they look neater but is it worth the extra effort?

[bigherb]

I assume they where compression fittings. Did you use sealer on the joints? Calor gas recommend Calortite which is actually Red Hemetite sealer.

[lloydy]

yep, non setting gas seal smeared on the olive/shamfer of the compression fitting. Not on the threads as that does bugger all. Should seal without though, are you sure your not over tightening?

[Oldiebut goodie]

Are you using brass or copper olives? - I find that copper ones give a better seal in smaller bore pipework. Brass ones can crush the copper before giving a seal quite easily. Have never needed to resort to jointing compound on compression fittings though. Are you pushing the tube fully home as this can prevent a good seal as you crush the end of the tube also instead of the olive being the only thing making contact. Leave a small gap between the end of the tube and the fitting before you tighten.

[CovKid]

Mine is copper from the heater for about 2 feet, then rubber pipe to bottle. No leaks. You could do all copper but would need to coil it at some point to allow enough movement to disconnect/reconnect bottle. Personally I prefer rubber pipe to copper - works for me.

[Oldiebut goodie]

Calor specify compression fittings but there is a lot to be said for rubber solely for short lengths - so long as it is renewed regularly. My view is that by adding compression fittings to a length of copper pipe you are increasing the mass that is available to vibrate with consequent increased liability to fracture at clipped/clamped point. Ideally clamping each fitting and clipping pipework at short intervals would suffice in the majority of cases. I am with the rubber hose brigade provided renewal is carried out regularly within the working life on the hosing. The majority of van fitments have such a short run between bottle/tank and appliance that it is impractical to use cu pipe. I know that my pipe would need to be in the region of 20".

[lloydy]

I would use rubber if you just have one appliance, it does make sense. Regs say no though.
You can buy varying lengths of braided hose with compression fittings either end. Check out places like BES.

[CovKid]

Agree. Fixed copper pipe (unless you have a coiled section) only reliable if you have a dedicated tank, regs or no regs. If you have to change the gas now and again (ie bottle), I can't see a more practical way as you need some flexibility built in.

[123-jn]

I have had problems with leaks on small compression fittings but usually when I was putting them back together using an existing joint. When using new fresh pipe and fittings with copper olives I usually do them up finger tight then 1/4 turn at a time using very soapy water sprayed on and around to check for leaks, you rarely need to go more than 3/4 for a good seal. I also use a very short spanner (3 inch) this helps stop you going too far. Once you have tightened too far the only cure is start again new pipe and new olive. Some olives when you get them are not barrel shaped they are more like rings, these require a tad extra 1/4 turns as I have found out. Some fittings for gas use a stepped olive which is much longer, you tend to find these on manifolds and cookers etc These must be replaced like for like.

[paperhouselad]

Great thanks all for the valuable input, something to work on over the next few days.