new gas line couplings still leak

[AlbertF]

The short gas line from the rearmost valve to the water heater on my trailer had a leak at the water heater end. I tried tightening it, to no avail - big bubbles. I had a new copper line made up - single flares, with new couplers. However, I still get small leaks, now at each end.

What do I do now? Is the quality of the flaring work a potential issue? The flares look a little rough, can I cleaning them up with some emery cloth? Or do I just need to tighten things even more than I already have?

Help would be appreciated, because I'd like to have hot water again!

[thecatsandi]

WHat do the mating surfaces look like? are they clean and free of dirt and defects? if not They need to be. Over tightening will reslt in failure of the the joint.

[63air]

Could be bad flares, some of the cheap Chinese tools make bad flares, I broke down and spent the $50 bucks for a Rigid tool - no problem now. You can also overtighten or not be properly aligned and get a leak.

Find someone with a good tool to remake the line and be careful when you tighten it. You can do it yourself , check with any mechanic you now, they'll have a flaring tool.

[dwightdi]

Actually, the current required standard for gas lines for RV's is to use double flares. Check to see if the fittings in the water heater require you to use single or double flares. Your unit might have single or double fares originally.

[nickcrowhurst]

Albert, I use a pipe joint compound made for use with LP gas. This is a different compound and color to the usual water pipe compound. It is shown, well down the page, as a yellow compound here:
Thread Sealant Compounds Product Info and Reviews | DoItYourself.com
It works for me.
Nick.

[Fyrzowt]

With a flare fitting, isn't the seal at the face of the flare and not the threads? I don't see the point of sealing the threads.
Dave

[AlbertF]

Originally Posted by Fyrzowt

With a flare fitting, isn't the seal at the face of the flare and not the threads? I don't see the point of sealing the threads.
Dave

That's what I thought. It's a compression fitting, and it's now clear to me that a high quality mating surface is essential. The flares don't look that good; the copper seems to be a bit mashed looking. Somebody at a hardware store flared the lines for me with an old tool. Part of the problem, I guess.

I knew that double flaring was required for car brake lines, but didn't expect that with low pressure gas fittings. If single flares don't work, I'll try doubles.

First, I need to find my own flaring tool!

Thanks to all for the help.

[nickcrowhurst]

Originally Posted by Fyrzowt

With a flare fitting, isn't the seal at the face of the flare and not the threads? I don't see the point of sealing the threads.
Dave

That''s why I put it on the flare. As designed, the flare should self-seal, but, if not, a smear of the paste seals it for me , and minimizes the torque required to make the seal. I've used it as a "get me out of trouble" fix, for example on my sailing yacht, a long way from a hardware store.
Nick.

[Fyrzowt]

Thanks Nick,
Sorry, I thought you were referring to sealing the threads.
Dave

[nickcrowhurst]

Originally Posted by Fyrzowt

Thanks Nick,
Sorry, I thought you were referring to sealing the threads.
Dave

Dave, I should have been more explicit. Nick.

[AlbertF]

Originally Posted by 63air

Could be bad flares, some of the cheap Chinese tools make bad flares, I broke down and spent the $50 bucks for a Rigid tool - no problem now. You can also overtighten or not be properly aligned and get a leak.

Find someone with a good tool to remake the line and be careful when you tighten it. You can do it yourself , check with any mechanic you now, they'll have a flaring tool.

Good advice!

I bought a cheap Chinese tool, since it was the only thing I could find in a retail store . . . and I still can't solve the leak problem completely. (Been busy with house renovation work, just got back to dealing with this issue.) I am going to need to find a good quality tool, as recommended. However, I'm becoming quite comfortable about messing with gas lines. A spray bottle with a bit of soapy water is very effective at unmasking leaks.

[Ganglin]

AlbertF - we just installed a new hot water heater - used a 3/8 flex line from Home Depot they come in 2 foot and 3 foot lengths - no flaring required and easier to install. Make sure the male fitting is clean as mentioned above.

[jimmickle]

A good double flaring tool should be available at your local auto parts store. Once you have a double flaring tool, you will never single flare again. If they don't have one, check with one of the tool trucks like Snap On.