Can I splice the water heater gas supply line to add a dryer?

[asr9754]

I have a 1/2 inch gas supply pipe, then a shutoff valve/reducer to 3/8, then 3/8 flex pipe to hot water heater.
Hoping to splice-in so I can install a gas dryer. The 1/2" main gas supply is very short and threads look pretty sealed, so can I splice in a T splitter "after" the shut off valve?
(I'd put a secondary shut off on the dryer line just to be safe). Pic attached, Thanks!

 

[RS]

You could, but you would get better volume if you would remove the existing valve and put a 1/2 T on the stub pipe, and then have a separate valve for each appliance. Be careful unscrewing the valve, hold the pipe coming out of the wall with a back-up pipe wrench, if it turns in the wall it will have to be removed and re-sealed. It's possible you may not have enough volume to run both appliances at the same time. But they might operate on reduced heat or you may just have to use them one at a time. Water heaters are about 30,000 btu's, I don't know offhand what dryers are. There also needs to be a drip leg for each appliance.

 

[MicEd69]

It appears that the original installer has welded a copper ground cable to the valve to bond it to the supply pipe. So, if you choose to add a tee to the 1/2" supply line, you should remove the cable clamp from the pipe, so you have room to use a pipe wrench. I'm not sure why the valve is bonded unless there is a local code that requires it.

While adding a 1/2" tee ahead of the valve would be best, you will probably be OK using a tee after the existing valve. But I would suggest you use a full port valve to the dryer and use soft copper tubing with flared connections all the way to the dryer instead of those yellow corrugated gas lines. The smooth copper tubing will provide minimal pressure drop to the dryer.

 

[Twowaxhack]

You can’t screw a tee onto those flex line threads that’s there now. Those are not IPS threads. It’s a flare fitting.

Unscrew the valve and install the tee on the steel pipe. Leave the ground clamp in place, use a backup pipe wrench between the existing valve and clamp as a backup to prevent the nipple in the wall from moving.

You may or may not have enough pressure to add the dryer.

 

[MicEd69]

Twowaxhack is correct, you cannot use a standard pipe tee with IPS threads. You will need a 3/8" flare tee and a 3/8" flare coupling (which is really a union of sorts).

And yes, you may or may not have enough pressure for this additional load. While adding a tee ahead of the valve would be best, the difference between that and using the flare tee is minimal. A gas dryer does not fire during the entire dryer run. And even though you are obviously washing clothes and likely using some hot water requiring the water heater to fire at the same time as the dryer, the impact will be minimal.