View Full Version : Does a modern natural gas appliance need "drop pipes/condensation drops"?


Cobra4B
01-11-2010, 10:35 PM
The gas line for my stove and lines to my hot water heater have what looks like condensation drops you see in air line systems.

Range line
http://i39.photobucket.com/albums/e158/cvbowers/House%20Remodeling/DSCF3749.jpg

Water heater
http://i39.photobucket.com/albums/e158/cvbowers/House%20Remodeling/DSCF3750.jpg

The new gas range doesn't have the space on the backside for the existing gas line setup. Because of this it won't slide back to the wall and I need to modify the gas line. All modification will happen after the existing shut-off valve.

Can I just remove the vertical section of pipe (all of it, above and below horizontal part) and attach a new flex hose to the remaining male end to the range? Or, does that drop pipe serve some needed purpose?

My GF's father is a master electrician and a very experienced all around handy-man and told me he'd never seen that and his range doesn't have that at all (they recently replaced theirs too).

Just trying to understand what I'm looking at and what I need to do to do it correctly :beer:

Thanks,

Brian

therealjakeg
01-11-2010, 10:41 PM
I work for a gas supplier here in the southwest and it is not required by us. There is so many filters that would not even imagine. Theres no moisture in the lines. The only thing thats in there is the cutting oil from the plumbers doing a sloppy job. They just hope the oil falls to the bottom. I think the cities and counties code it as well but once again theres nothing in that line to worry about. Not a big deal. If it was how would you get it out? You cant purge the water out of the line with gas right? That would be dangerous. We dont want out customers using the natural gas as a purge supply. Take it off and just run it normal with a shut off Valve.

Falcon67
01-12-2010, 12:08 AM
We've lived only in houses with gas - never all electric. Never seen a drip leg on a gas stove.

Cobra4B
01-12-2010, 12:44 AM
Take it off and just run it normal with a shut off Valve.
So you're saying I can just remove the vertical tubing and T-pipe and run my flex hose to the remaining horizontal pipe after the shut-off valve right? No reason I need to change the valve assembly or anything right?
We've lived only in houses with gas - never all electric. Never seen a drip leg on a gas stove.
So these are called drip legs?

Thanks for the education :beer:

nate379
01-12-2010, 05:12 AM
Some places you need them, others you don't. Don't usually see them on gas stoves or dryers, but on the water heater and boiler.

Don't need them here by code/requirement, but many install jobs have them anyhow.

The gas pipe being in front of the electrical outlet seems like a big no no though!

Cobra4B
01-12-2010, 09:10 AM
^ Good point... well it'll be gone shortly when I remove it. I'm guess whoever plumbed the house back in '89 just did it out of habbit.

lawfarm
01-12-2010, 11:18 AM
My understanding (and I could be wrong) is that the 'drip leg' isn't for condensation, but rather is there to catch anything that could be in the pipe (flake of rust, etc) before it gets into the appliance and plugs a burner / orifice / valve.

Cobra4B
01-12-2010, 11:24 AM
^ That makes sense... maybe not required, but just good practice?

kbs2244
01-12-2010, 01:21 PM
Yeah,

They are called "drip legs" but are really for dirt, rust flakes, etc.
Sometimes called for by code sometimes not.

For some reason they are sometimes called for if the connection is "permanent" (all hard pipe) but not if the hook up is done with a flex pipe.

I never learned the reason for that.

ddawg16
01-12-2010, 01:26 PM
My understanding (and I could be wrong) is that the 'drip leg' isn't for condensation, but rather is there to catch anything that could be in the pipe (flake of rust, etc) before it gets into the appliance and plugs a burner / orifice / valve.

That is my understanding as well. Most gas lines are ver low pressure...typically around 2 psi....so it's not like it's going to blow a lot of stuff down the pipe....I think you could use the following guidlines...

If your feeding gas 'up' to something....you don't need it....especially if it's a 1-2' rise....

If you have a long horizontal run then a drip leg at the end would be a good idea....

When I installed the central air up in the attic, I installed a drip leg right where the furnace line connects....just to catch any left over slivers of metal that might have been left behind when I threaded the pipes...

Cobra4B
01-12-2010, 01:28 PM
Thanks for the feedback guys... learned something new.

therealjakeg
01-12-2010, 10:59 PM
So you're saying I can just remove the vertical tubing and T-pipe and run my flex hose to the remaining horizontal pipe after the shut-off valve right? No reason I need to change the valve assembly or anything right?

So these are called drip legs?

Thanks for the education :beer:

Yep sure am just dope that fitting then tighten it on but dont dope the flex it has a machine end with the flared fitting. Best of luck

Cobra4B
01-12-2010, 11:31 PM
Can you clarify? You said dope the fitting the tighten it on, but don't dope the flex line. Do you mean don't dope the joint at all, or are you saying apply the dope on the male threaded pipe then thread the flex line on?

metal1313
01-13-2010, 12:38 AM
dope the t, and the plug you insert. the flex line should not be doped, and the dope can cause problems with them. id replace the the flex line depending on age as well

Cobra4B
01-13-2010, 09:52 AM
But I'm talking about getting rid of the T and vertical pipes copletely. I just want to hook my new flex line up to the horizontal male pipe that is after the shut-off valve. My new range won't slide back to the wall unless I ditch that T and vertical part of pipe.

So if I'm reading everything correctly I can remove the T-fitting and 2 pieces of pipe with it (obviously I'll have to remove the 2 vertical pipes to allow room to rotoate the T fitting off). Then I can thread the new flex hose one the remaining male pipe end and do so w/o any dope. I did notice that the old flex hose was devoid of any dope/sealant, it looks to have an internal compression seal. And yeah... I plan on replacing as the one I took out was 20 years old.

Falcon67
01-13-2010, 11:29 AM
Our range is on the end of a 3/4" (why so big not sure) horizontal pipe with a shutoff right on the end of the pipe. Then flex line to stove. I would use gas compatible teflon tape with a bit of sealant. Gas pressure in a house is really low, measured in inches of water column.

W-Cummins
01-13-2010, 12:35 PM
That is my understanding as well. Most gas lines are ver low pressure...typically around 2 psi....so it's not like it's going to blow a lot of stuff down the pipe....

Not even close, The lines in your home are normally run at 7" H2O = about 0.2526 psi. William....

Willy Victor
01-13-2010, 04:49 PM
The shutoff has to be in the same room as the appliance.


Willy

Bill K
01-13-2010, 05:09 PM
A couple of things here for th OP
ARe you replacing an existing gas range or installing a new one?
If this is a new install I HIGHLY recommend contacting your building dept and see if you need to have it permited and inspected. Reason I bring this up is that if you are required to pull permint and undergo inspection and do not AND you ever have GOD FORBID a fire or gas explosion etc your insurance can deny the claim flat out.
I notice there is no regulator at the water heater. Most homes built now have a 2lb system with a regulator to drop the pressures down at each appliance. Other systems are at 1/2lb set at the meter. These system usally are 3/4 black pipe as you need the size to ge the correct amount of gas. If you put too may appliances on an older 1/2 lb it can starve for gas and not burn as effecient. Then you have to switch over to a higher pressure system. This usally happens when people add a gas log set or two and gas stove to an existing system. They want notice a problem till moms cooking dad's taking a shower and the furnace is running with a set of logs burning.

Cobra4B
01-13-2010, 05:32 PM
I'm replacing my existing gas range. The new range won't slide in place because it won't clear the verticle portion of pipe in the first picture. The old range obviously would. I simply made this post to verify what my GF's father said about removing the vertical pipe and runnnig the flex hose directly to the remaining horizontal pipe.

Bill K
01-13-2010, 05:43 PM
Cool better safe ya know. Most of the drips here are only a couple of inches long. You could come off the horizontal. There is a valve with 3/4 pipe thread on one end and fitting on the other for a flex. Shame you are not closer I got a pile of em I've picked up off jobs this past few months.
To clarfiy use pipe dope on the 3/4 pipe end and nothing on the flex connection, it is a compression type much like a brake line.

W-Cummins
01-14-2010, 01:54 PM
I notice there is no regulator at the water heater. Most homes built now have a 2lb system with a regulator to drop the pressures down at each appliance. Other systems are at 1/2lb set at the meter.

Are you sure about that?? 2 psi is a medium pressure system and requires externally vented regulators.
As I stated above, most systems are 1/4 psi and any higher than that you would need regulators at each appliance. I have heard of some places running 1/2 psi and then regulating it at the point of use for residential use. A 1" line at all most 400' long @ 2psi will provide over 1 million BTU's


William