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jamlove · Apr 9, 2007, 09:17 AM

Hello all,

I'm not sure whether to ask this question in the heating forum or here, but it seems to be more a piping question. I am installing a gas fireplace. I got it used, and pieced it together from two sources, meaning I'm needing to change a few things.

The burner I got was configured to have the gas come from the right. But the firebox I got from a different place already had the knockout on the left. I removed the cap from the burner and am placing it on the other end, so the supply connection will be on the left now.

I'll be connecting a flex copper hose, with brass fittings, to the supply line.

The question is: Is there a special type of pipe joint compound I should use in this high-temperature location?

I have joint compound right now that I've used for all the black steel pipe, which is gray and never hardens. It doesn't specifically say it's flammable, but I'm wondering if there is stuff made just for this purpose.

Any suggestions appreciated. Thanks!

iamgrowler · Apr 9, 2007, 09:43 AM

Originally Posted by jamlove

Hello all,

I'm not sure whether to ask this question in the heating forum or here, but it seems to be more a piping question. I am installing a gas fireplace. I got it used, and pieced it together from two sources, meaning I'm needing to change a few things.

The burner I got was configured to have the gas come from the right. But the firebox I got from a different place already had the knockout on the left. I removed the cap from the burner and am placing it on the other end, so the supply connection will be on the left now.

I'll be connecting a flex copper hose, with brass fittings, to the supply line.

The question is: Is there a special type of pipe joint compound I should use in this high-temperature location?

I have joint compound right now that I've used for all the black steel pipe, which is gray and never hardens. It doesn't specifically say it's flammable, but I'm wondering if there is stuff made just for this purpose.

Any suggestions appreciated. Thanks!

Sounds like you're using 'Pro-Dope', which should be fine for your application.

If it isn't and you're still unsure what to use, then just use Teflon tape on the threaded fittings in the fire box.

jamlove · Apr 9, 2007, 09:59 AM

Thanks, maybe I'll use the tape.

Another quick question to you pro's: I'm using half-inch black steel pipe here. Exactly how tight do you need to crank that stuff?? I mean, I've tightened the HECK out of every joint using two 24" pipe wrenches. At this moment, I still have a very slow leak somewhere! I pressure-tested my little branch to the fireplace, and in a day it goes from 20 psi to 10 psi. That's pretty slow, but still not OK. It's so slow that I can't find any bubbles even.

Any other tricks I can try here? Hey, I could WELD all the joints! :) Just kidding.

iamgrowler · Apr 9, 2007, 10:19 AM

Thanks, maybe I'll use the tape.

Another quick question to you pro's: I'm using half-inch black steel pipe here. Exactly how tight do you need to crank that stuff?? I mean, I've tightened the HECK out of every joint using two 24" pipe wrenches. At this moment, I still have a very slow leak somewhere! I pressure-tested my little branch to the fireplace, and in a day it goes from 20 psi to 10 psi. That's pretty slow, but still not OK. It's so slow that I can't find any bubbles even.

If you're dealing with Seattle inspectors, they are going to require a 30lb gauge pumped up to 15lb's -- Anything under or over is going be automatically failed.

They will also expect the piping to be tested through the shut-off, meaning you will need to cap the gas off where it enters the fire box with the gas valve in the open position.

As for the leak -- Is the new gas piping completely isolated from the old gas piping with a shut-off, or are you testing the entire system?

If you're testing the entire system, you need to make sure you are disconnected and capped off at the meter and that the shut off valves at other gas fired appliances are shut off -- Blasting 20lb's of pressure through a low pressure regulator might explain the minuscule drop in pressure.

jamlove · Apr 9, 2007, 10:30 AM

At this stage, I'm only testing the new branch for the fireplace. It is not yet connected to the main supply line... all I'm doing is making sure my work so far (including the firebox portion after the shutoff, like you said) is going to hold pressure, before I connect it to the full system for inspection.

I'm just having trouble finding the leak since it's so slow. I bought special bubbly stuff in the piping section, but so far no luck finding the culprit (although, yesterday before I fixed it, the leak was coming from the Pressure Gauge itself! Cheap Home Depot junk)

I had a nice brass gauge but it cracked!

Anyway thanks for the advice.

iamgrowler · Apr 9, 2007, 10:43 AM

[QUOTE=jamlove]At this stage, I'm only testing the new branch for the fireplace. It is not yet connected to the main supply line... all I'm doing is making sure my work so far (including the firebox portion after the shutoff, like you said) is going to hold pressure, before I connect it to the full system for inspection.

I'm just having trouble finding the leak since it's so slow. I bought special bubbly stuff in the piping section, but so far no luck finding the culprit (although, yesterday before I fixed it, the leak was coming from the Pressure Gauge itself! Cheap Home Depot junk)

I'm not a big fan of the bubbly stuff, I usually just use Dawn dish detergent and water in a spray bottle.

You should try McClendons for the test gauge and make sure you're also spraying the little fill valve on the test gauge body.