We're having an issue with a quick disconnect coupling for an outdoor gas grill. The owner downsized and moved to a smaller home in the same subdivision. It is a natural gas grill that was connected to the house gas in the old house, but cannot connect at the new house.

Their grill hose has male connector marked ANSI Z21.54 CSA 8.4. Female connector on the old house is marked ANSI Z21.41 CSA 6.9, and has three ball latches. Female connector on the new house is marked ANSI Z21.41 C, and has six ball latches. The hose goes in and bottoms out close, but not enough, for the balls to latch. There's no apparent damage to or blockage of either of the couplings.

In my research I couldn't find a comprehensive table or comparison of different types of connectors, or if there are, indeed, differences. I've seen some city mechanical/building codes specify particular edition of the standard (e.g. ANSI Z21.41-2014), but no descriptions. CSA bit appears to be a reference to Canadian Standards Association, so it's not necessarily helpful.

How do we ensure that we get proper connector, or diagnose the problem with the existing one?

  • page 3 of this document implies that ANSI Z21.54 is for outdoor gas appliances ... nfpa.org/Assets/files/AboutTheCodes/54/… ......... the connector at the old house may be mislabeled .... and the new house may have the wrong connector
    – jsotola
    Mar 23, 2020 at 20:00
  • @jsotola, I've found that Z21.54 is a gas hose connector standard (ANSI), and Z21.41 is a matching quick disconnect on the supply side (ANSI). All the connectors in question aren't simply labelled, they are stamped in metal.
    – theUg
    Mar 23, 2020 at 20:13

2 Answers 2


There are purposeful differences in gas line connectors between portable PROPANE systems and NATURAL GAS systems typically found in houses when supplied by gas utilities. The reason they are different is because the GAS is very different and they are NOT interchangeable. ANSI Z21.54 is for PROPANE, ANSI Z21.41 is for NATURAL GAS. They don't match up because they are not SUPPOSED to match up.

  • 1
    Problem is, the Z21.54 worked in the old house no problem, and the new owner at the old house also has the same connection. Moreover, I'm looking at PDF info sheet from Dormont/Watts for their appliance hoses that says Z21.54 is a gas hose connector, and Z21.41 is a quick disconnect.
    – theUg
    Mar 23, 2020 at 19:35
  • 1
    From ANSI itself: use with natural gas , manufactured gas, mixed gases, propane and LP gas-air mixtures.
    – theUg
    Mar 23, 2020 at 19:44

Sounds like you have a grill that is designed for propane and trying to connect it to a natural gas line. Because the thermodynamic properties of the two gases are different, the connectors and valves used for each gas are different.

They do sell natural gas conversion kits for propane grills. I would recommend getting one of those for this.

  • It's a natural gas grill that was connected to the house gas previously. See the comment to the earlier answer.
    – theUg
    Mar 27, 2020 at 13:55
  • From what I can tell by looking up the different times, looks like they are different connectors from different years. As new specifications are written, new connector specs are drafted as well, each getting a new version. You'll need to update the grill connector hose to one that matches the specs of the house connection point.
    – almostengr
    Mar 27, 2020 at 14:12

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