How to hook up a new gas range with mismatched fittings, and meet all code requirements?

Question

The connection on the stove appears to be female 1/2" NPT. The 3' long yellow flexible connector has a female flare connection with a 15/16-16 thread at both ends. At the stove end there is a male/male adaptor that converts the flare connection to 1/2" NPT. The same adaptor is at the other end (in the picture).

The gas supply line (no valve now) has a female 5/8 OD flare (7/8-14 Thread). The old valve is in the picture. New valve is arriving by FedEx. To make the new valve work, I have purchased a bushing 3/4" NPT (valve end) to 1/2" NPT (adaptor end). Note: It took half a day to even find a valve that would fit the 5/8 OD flare (7/8-14 thread) that was useful in this case. It is a Legend 102-114.

Questions: 1. Does the "NEW" solution described below meet US codes in general (I know that codes vary from Jurisdiction to jurisdiction)? 2. Should there be a ”Safety+Plus®2” (in the picture) in place of the steel adaptor at the supply end (my connector set did not include it, but many at the store had it). 3. Why are there two 5/8' OD flare connectors in existence with different threads? This complicated everything.

For clarity: Gas is propane, all fittings except the new yellow flexible connector and the adaptors supplied with it are brass.

ORIGINAL (supply to range): 5/8” OD copper pipe supply with female brass flare (7/8-14 thread); to brass valve with two male flare (7/8-14 thread); to 5/8” OD copper pipe with female brass flare (7/8-14 thread); to old stove (fitting unknown)

NEW (supply to range): Original 5/8” OD copper pipe with original female brass flare (7/8-14 thread); to new brass valve with one male flare (7/8-14 thread) and one female 3/4' NPT; to new brass bushing 3/4 Male NPT to 1/2 Female NPT; to new 1/2 stainless or chromed steel adaptor Male NPT to male 5/8 OD flare (15/16-16 thread), supplied with new flexible yellow connector set; to female 5/8 OD flare (15/16-16 thread) on yellow connector (same at both ends); to new male 1/2'NPT, and into the stove.

The installers that brought the stove and attached the new connector to it were unable to complete the connection at the supply end. Supply House has the identical new Gas Connector kits (adaptor; to yellow flexible tube with flare fittings); to adaptor or safety valve. But nothing that will adapt to the 5/8 OD flare (7/8-14 thread). And yet, in their brass fittings section, all 5/8 OD flare fittings were the SAE standard 5/8 OD (7/8-14) thread.

Answer 1

I normally install the shutoff directly on the incoming gas line this way there is less chance of an issue. after the valve I install a flair adapter to match my flex gas tube . I prefer gas rated pipe dope for gas but there is a gas rated (yellow tape) for those that prefer tapes.

I rarely order fittings on line and tend to use speciality shops not big box as they always have the correct fitting I need and many times helpful advice , yes the part might cost a dollar or 2 more but I get the correct parts that match the first time and don’t end up with a bunch of adapters or cobbled together parts.

The bonus about specialty stores is that they usually do know local codes and this project may be a good reason to give them a visit, I am not sure about the flair fitting prior to the valve that would bother me. I have done a bunch of gas pipe work on my own homes including new gas services in several, but am an electrician by trade.

Answer 2

You don't have to use the adapters supplied with the yellow gas hose if they're not needed.

You can hook it up how it was with a 5/8 flare valve connected to your copper line, then connect the yellow hose directly to that without an adapter. Then on the stove side use the supplied adapter to adapt from the hose's female flare to your stove pipe thread inlet.

Answer 3

My understanding is the gas fitting was changed (maybe 50 years ago) because the old 5/8 flare adapter threading was ALMOST a match for threaded pipe resulting in DIY leaks from threading a pipe threaded adapter onto the flare fitting. The current fitting won't mismatch to anything unsuitable. 40 years ago when I replaced a gas stove an old fashioned hardware store had an adapter that screwed onto the old style and presented the new style. The better action now is to put in a new valve on the gas pipe, but the downside is that this requires shutting gas to house off, and may require the gas company to turn it back on.

Answer 4

I just ran into this myself, this evening.

I have a theory:

The flex lines to the appliance are rated different than copper in the wall to withstand occasional flexing if the appliance is moved, and are now usually stainless steel (and coated for secondary protection if a crack develops). They require fittings made of steel, not brass, and bear the marking "SS" on the fitting, designating that it is approved for stainless steel flared tubing.

Stainless steel is harder than copper or brass(?), and my understanding is that the tube flare is intended to deform (like a metal gasket), and not the fitting. So the fitting is harder than the material being connected AFAIK.

My guess is they changed the thread to assure that SS is not installed into a brass flare fitting. Also, fine threads 'pull' more torque than coarse thread, and this would make sense, as SS (which is harder than regular steel) would need more torque to insure proper sealing.

PS, uncoated brass flex is now prohibited in the code IIRC, and I believe it is required for you to change it out, if encountered (with coated SS flex line).

I myself bought my house with an existing stove (which I never moved, but my wife cleaned behind it once or twice; and the uncoated brass line blew one night! (split open).

Mr K L