Gas line entering HVAC cabinet

[rlskfoster]

I know we aren't supposed to have the flexible gas lines enter the HVAC cabinets to connect to the regulator but what about the newer coated(yellow) flexible gas lines that are being used to replace the old black ridgid pipe?

Buster

[Bain]

The lack of answers to your question shows that it is a good one. Where I am, the yellow line always has a transition to rigid pipe just outside the cabinet, but I don't know of any rule governing this.

[DonTx]

Gastite (CSST) has a 100 page design manual that covers just about all types of installations. Although I haven't read the entire thing, one of the "Do's" is to "protect it from contact with sharp objects", such as furnace cabinets.

I think the IRC may even address this. I call it out every time I see any type of flexible gas line entering a furnace cabinet.

[hausdok]

Originally posted by Bain

The lack of answers to your question shows that it is a good one.

It's a good question, but the reason he wasn't getting any answers earlier in the day is probably because everyone was out working. I try to keep my nose out of here during the day or I won't get anything else done.

That said, I've read the Gastite manual and I don't remember a specific prohibition against it. I do remember a requirement to ensure it isn't installed where it will be abraded by sharp edges. However, there is also a requirement for a drip leg.

The code prohibits a 'connector' from passing through any floor, wall partition or appliance housing. Strictly speaking, I guess these can be interpreted as being connectors.

Around here, there is usually a wrought iron pipe coming off the gas valve that extends through the side of the cabinet and has a drip T on the end before it connects to the CSST.

OT - OF!!!

M.

[Gordon]

I know we aren't supposed to have the flexible gas lines enter the HVAC cabinets to connect to the regulator but what about the newer coated(yellow) flexible gas lines that are being used to replace the old black ridgid pipe?

------------------------------------------------

Concerning the newer flex's, are you talking about CSST? Around here, I've never seen CSST used that way, though I wouldn't doubt its existence in this manner. What I have seen, is flexible piping going through the furnace housing, walls, floors...all of which are not acceptable. All flexible piping needs to be secured from excessive vibration, and I would add CSST to that list. I've come across many homes where the piping wasn't secured, and people have dropped objects on them, stepped on them, or just accidentally "brushed" a flex right at an acute bend, & all have created stress fractures, creating a gas leak. After more than 20 yrs. working at the gas company, I thank the Good Lord I never had to respond to an explosion like some people I know...but I easily could have!!

Another concern as it passes through from the pipe into the furnace, is the condition of the pipe around the sharp edges of the metal housing. The flex isn't strong enough to withstand movement up against these edges. Also, if the flex is epoxy coated, most likely it'll mean a brass connector. Once the brass is exposed, then oxidation can occur. I've attached a few pictures for an example of the above concerns.

In my humble opinion, flex connectors should only be used for ranges and dryers (the exception is for Lennox Pulse furnaces, which "requires" a flex installed so it won't shake the gas piping in the entire house when the furnace pulses, but the flex still needs to be installed in a position that will keep it safe). Hard piping should be utilized, and the only reason (again my humble opinion) I can see why plumbers/contractors use flex's, is it's easier to install than hard piping. Some areas have codes against flex's used in this manner, some don't. Either way, it's not the best use of this product when installed this way.

To go a bit further with CSST-I've only seen CSST used through walls, and there needs to be a strike plate as it passes through studs/joists so it can be protected from nails puncturing it. Of course, you'll never see this once the dry wall is up, so you won't be able to make an assessment. But I would still put it in the report, to make sure the client knows.

Ok...I'm off my soap-box concerning this subject!

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[Jim Katen]

Originally posted by rlskfoster

I know we aren't supposed to have the flexible gas lines enter the HVAC cabinets to connect to the regulator but what about the newer coated(yellow) flexible gas lines that are being used to replace the old black ridgid pipe?

Buster

Buster,

From the Gastite manual, page 42:

Where it is necessary to install Gastite® through sheet metal enclosures such as

gas fireplaces, and vibration from motors could cause mechanical wear, the plastic

jacket should remain intact and the tubing should be routed or supported to prevent

direct contact with the enclosure. If direct contact can not be avoided, protection

such as grommets, metal conduit or rigid pipe may be used.

- Jim Katen, Oregon