Update - Thanks for all of the answers and comments - I am including some more info and pictures to try to give a better sense.

A professional is coming tomorrow to take a look, they are the one who gave me the idea to try to replace the old burner myself in the first place - according to them it is completely legal in my area and they are happy to inspect if it is done correctly. I'll also add that we bought the house recently, and as far as I can tell the gas fireplace could not have been used for at least 10 years.

I’m trying to install a new gas burner on an old gas fireplace. There is a rigid gas line that comes up from the basement. From that point it is hidden behind a wall, until there is a valve key/escutcheon. There is a ball valve on the rigid line in the basement which is closed. I've tested both that valve and the valve key - no gas currently flows unless both are open, so seems like we are safe there. At some point behind the wall the rigid line must be connected to a flexible appliance connector. There was an old, very rusted burner attached at the end, and when I tried to get it out I accidentally broke off the end of the flex connector. I can only reach about an inch of the end of the ripped line, the rest is behind the fireplace and wall, inaccessible.

Is there any way to safely connect a fitting or anything else to the line?

Rigid line from the basement with closed valve: enter image description here

Valve key and fireplace with stub of the connector visible: enter image description here

Gas line stub:

enter image description here

Old burner: this was previously attached to the connector, I've since removed it as well as the fake brick wall to give more access to the gas line:

enter image description here

  • 19
    Gas(natural or propane) is one of those things that need to be done right, no make do things. You already broke part of the line, need to know the rest is perfect before using.
    – crip659
    Commented Dec 15, 2021 at 16:55
  • 2
    Let us know in an update whether you were able to get in the space, connected and working. Would be valuable to many other readers. With your valve before the connection it's easier to test (very important) and cautiously start operation.
    – P2000
    Commented Dec 15, 2021 at 20:40
  • 1
    Perhaps you could sketch the situation better, for everyone here trying to help: draw the walls, building materials of wall, the gas line, and include all details like size/type of tubing, valves / shutoff, distances, size/type of fireplace etc...
    – P2000
    Commented Dec 16, 2021 at 19:17

6 Answers 6


CSST terminations typically require that you wrench on the last inch or two of tubing, much like a compression fitting for plumbing. You'd need to gain a little slack there to accomplish a safe connection.

enter image description here


I'm not a Chicken Little and won't try to scare you away from working with gas lines. (By the same rationale none of us should be operating or fueling motor vehicles.) Just be sure you do it safely and properly in accordance with local laws. Test thoroughly, both with pressure and liquid leak detection.

  • 28
    " I ... won't try to scare you away from working with gas lines" - I disagree. Gas is dangerous, and is even on the "Never DIY this" list. This should be done by a professional
    – cocomac
    Commented Dec 16, 2021 at 5:05
  • 1
    When it all goes wrong, your insurance company will give no support as you didn't used an experienced, competent fitter. As often is the case, location would mean answers could be more apposite.
    – Tim
    Commented Dec 16, 2021 at 11:43
  • 5
    Dv on the grounds that there's not an inch or two to get a compression joint on, and local byelaws will most likely outlaw any amateur messing anyway.
    – Tim
    Commented Dec 16, 2021 at 11:59
  • 3
    +1 from me. A fitting or flex hose hookup doesn't require a professional if you do your due diligence. Most flex hose kits come with leak test solution anyway, and as long as you leave some time between turning on the gas and starting up your appliance, you'll smell a leak before it becomes a problem. That said, if it requires running lines through the wall, that's when I would call in a pro.
    – Dan A.
    Commented Dec 16, 2021 at 15:10
  • 4
    The only trouble is that OP says he broke an appliance connector. Though the materials are similar to HomeFlex and other CSST building plumbing products, it would be inappropriate to use a CSST fitting to repair an appliance connector even if the physical sizing makes it appear the fitting should be compatible.
    – Greg Hill
    Commented Dec 16, 2021 at 23:34

I would heartily suggest hiring a professional.
Where I live what you are doing is actually illegal.
Your territory may have different laws, but guessing with gas is never a good idea. It goes bang!

After comments, [many now deleted] hinting this may be a 'nervous response' or even 'not an answer'.
This is a Frame Challenge.
If you have to ask, you don't know enough about it to do it safely. You are certainly not qualified to handle live gas, which in most territories is likely to invalidate your house insurance & in others could bring prosecution.
Hire a qualified professional.

  • 7
    Interesting downvote for my suggesting someone doesn't blow themselves sky high. There is always the very obvious proviso with gas - if you have to ask you don't know enough about it to do it safely… so don't do it.
    – Tetsujin
    Commented Dec 15, 2021 at 18:15
  • 8
    @isherwood - surely that is territory-dependant. In the UK what the OP proposes isn't just downright dangerous, it's actually illegal. This isn't a 'nervous' response, this saves lives. Now the pictures have been added, this is a bomb waiting for one more DIY 'fix' before it goes off.
    – Tetsujin
    Commented Dec 15, 2021 at 19:18
  • 15
    @isherwood - I'm not questioning your competence, I'm questioning the OP's & anyone else searching this question. Also, your legal status as regards DIY on gas depends on your territory. As we don't know the OP's, then I can only state for mine, the UK, where this is illegal to DIY.
    – Tetsujin
    Commented Dec 15, 2021 at 19:47
  • 6
    I have to agree with @Tetsujin on this one, I've been on a BOC gas safety course, and one of the first things they show you is what happens when it goes wrong. You see a truck with just the cab & a pair of legs where they were transporting propane. One of the cylinders was leaking, the driver lit a cigarette and boom! The entire side of a building missing when an oxygen cylinder was mishandled, fortunately, the 2 workers were unharmed. And a piece of train track missing from a leaking Liquid Oxygen tanker. I would say getting gas wrong is more deadly than getting electricity wrong. Commented Dec 16, 2021 at 8:25
  • 6
    @isherwood: A valid answer to "Can I do xxx safely" is "No, you can't do xxx at all because it's illegal, whether you do it safely or not". (Such an answer may or may not be correct in any given situation, but it's not really fair to say it doesn't address the question.)
    – psmears
    Commented Dec 16, 2021 at 15:06

If the pipework broke there, who's to say what its condition is like further inside the wall? That apart, you're asking what to do. That means you're not qualified or experienced. O.k. There's a way to get experience, but not at the price of someone's life/limbs or property damaged. This just isn't where to cut your gas-fitting teeth. Leave well alone, it's going to be money well spent. Or cost you dearly when it goes bang.

  • +1 for the first sentence.
    – FreeMan
    Commented Dec 16, 2021 at 12:47
  • 1
    "Or cost you dearly when it goes bang." Or cost someone else, like a neighbor or a future owner of the house.
    – Dan C
    Commented Dec 17, 2021 at 16:55

I hate working with gas - and would strongly recommend getting a pro to fix it.

The pipe does not look in good shape either - I suspect the "proper" fix will be to replace the last piece of pipe into your hearth with a longer one, to give better access and also confidence in the pipe.

That may mean pulling the pipe back out through the bricks and re-doing with modern materials, and re-grouting around the entry.

And since you're going to that much effort, may as well replace as much of the gas line as you can reasonably get access to.


(Edited based on added information from the OP)

As a DYI-er you could do gas fitting under supervision and inspection, and in readily accessible spaces. But if the space is tight, and you are unable to recognize from your own knowledge and experience what details for gas fitting must be provided up front in such a question, it's time to get a professional involved. As a DIY who hasn't done this you can't really see or assess what is fitted/sealed right/wrong especially in tight spaces, whether fitting are compatible, and whether any code or requirements have changed in your region.

  • DIY but also get a professional involved (as you have now done - good move). Be prepared to pay for consulting and an inspection by the professional. It can be an informal "ok", but if you get an inspection letter that would be best.

The consulting up front will allow the pro to specify things like what fittings and materials you need and also to inform you about things you did not know that you had to know, like compatibility, pipe diameter, flow/pressure regulators, shut offs, and any upgrades that would make sense to implement now that you are involved with gas work anyway.

It is possible you have to do more work to replace other sections of the gas lines, and this is your chance to learn about it and do it right.

  • The ugly part: determine whether you need a permit from your local authority and whether the home insurance requires an inspection (these two can be different requirements). This usually just requires a few phone calls. Then decide what you want to do with that information.

A pro would speak from tons of real life training and experience -not youtube-, and most importantly (s)he would bring liability insurance. Also, without a permit or at least a qualified inspection your home insurance likely will not cover this repair or install. This matters for peace of mind around your asset value, the risk you pose to loved ones and neighbours, and possibly the resale value.

  • Get educated (my personal first joy of DIY work). Knowing what work is required, what fittings etc..you are armed with the right questions. Read up on it, watch videos, ask at your supplier etc... when in doubt or whether information appears ambiguous or contradicting, check back with your pro. Since you have a consulting/inspection arrangement they are in the best position to give you advice they can stand by and sign-off on.

  • Prepare a test procedure and start testing: include pressure testing (if required), bubble testing, stress/torque testing etc... Since you have two shut off valves in the path to the fireplace, you can work in stages without shutting off the gas supply for the entire house.

Torquing should not be underestimated: some fitting require specific torquing to tighten for a gas seal, other fittings can and should sometimes be banged with a hammer on a wrench to loosen without cracking the pipe elsewhere. I'd check in advance.

  • Where the work is difficult to reach, first practice on the comfort of a well lit table or work bench. You need knowledge and skills when it comes to fittings, tightening and sealing, and in comfortable well lit conditions you'll have more patience to inspect thoroughly and keep trying until done right.

  • Have it inspected, and enjoy the Holidays in the warm glow of your upgraded fire place which you can proudly and confidently claim to have installed yourself, done right. That's the third joy of DIY.

Gas work, framing, electrical work and plumbing (esp. drains) all require meeting specifications and safety standards. The risk assessment is different for each of these areas. For instance, safety with electrical work can be met if rules and specifications are closely followed, and this site can help get you there. Also, problems with electricity often show up during use, in the presence of observant users who can take action to remediate. (This can be argued, but I hope my point is clear in light of DIY sites providing help with electrical vs gas work)

In contrast, gas leaks can happen regardless whether the fireplace is in use or not, and in spaces under floors and in walls. Moreover, failures occur like a time bomb waiting for windows and doors to be closed, enabling a fuel build-up. This type of hook-up is not the same as an outdoor barbecue or gas fire pit.

PS: oh ya, the second joy of DIY? Tooling up!

  • 1
    This makes a lot of sense, thanks. One clarification I would add is that there is a gas valve key/escutcheon beyond this point, so there would only be gas flow when the fireplace is in use.
    – Thermidor
    Commented Dec 15, 2021 at 18:47
  • 2
    @Thermidor If it is the gas valve in the second picture don't count on it or any of the pipe. That is bad looking pipe.
    – crip659
    Commented Dec 15, 2021 at 19:19

the rest is behind the fireplace and wall, inaccessible

Huh, how did you shut off the gas before breaking it then?

Something is accessible so you should start with that something and run a new line. The existing line doesn't have enough accessible length for you to add a joint properly.

Based on your edit you need to disconnect this union and run new pipe. This of course assumes that the right side leads up to your fireplace.

enter image description here

  • OP mentions a valve "there is a gas valve key/escutcheon beyond this point", see comment under my answer. I think OP should sketch the situation better, for everyone here trying to help.
    – P2000
    Commented Dec 16, 2021 at 19:15
  • @P2000 Regardless, assuming OP is not currently high in natural gas and mercaptan then the only correct course of action is to get stuff replaced back to a healthy situation.
    – MonkeyZeus
    Commented Dec 16, 2021 at 19:23
  • Added some more info in the post. Behind the fireplace is both a valve key as well as a valve on the rigid pipe in the basement leading to the fireplace. Both were closed.
    – Thermidor
    Commented Dec 16, 2021 at 20:48
  • 1
    @Thermidor Thanks, see my edit.
    – MonkeyZeus
    Commented Dec 16, 2021 at 21:02

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