Sediment trap location w/ gas flex line

[Joseph W. Keresztury]

Here is a pic w/ my comment at a recent new home move in inspection where I called out that the sediment trap / drip leg should be before flex line (low side), of water heater.
Thoughts on this, please.
I had a debate w/ builders superintendent, who insisted that it should be right by unit, which as seen is in pic is on the high side of flex- not making sense to me since sediment, condensation, etc would settle better on low side of flex.

[Joseph Hagarty, CMI]

What is pictured is correct.

The sediment trap
should be as close as possible to the appliance.

[Joseph W. Keresztury]

Thanx Joe, here are a couple of images showing it should be the other way.

[Jeffrey R. Jonas]

Joe, I agree with Joe!

Pic in 1st post is correct.

2nd Pic... there is a difference in the setup, thus the difference in the sediment trap location.

Pic 3 looks like it may have 2 traps, but you blocked a portion of the 2nd one with your text box.

[Chuck Evans]

Originally Posted by jkeresztury

Thanx Joe, here are a couple of images showing it should be the other way.

Here's how Bradford White says to do it. If in doubt (and you think it really matters which side of the appliance connector it's on) research the specific water heater you are working with or check with your AHJ for local requirements.

Connect this water heater only to the type of gas (Natural or Propane gas) as shown on the rating plate. Use clean black iron pipe or equivalent material approved by local codes and ordinances. (Dirt and scale from the pipe can enter the gas valve and cause it to malfunction). The inlet gas line must have a minimum length of three (3) inches (7.6 cm) drip leg (sediment trap) installed as close to the water heater’s gas valve as possible. A ground joint union must be installed as close to the water heater as possible in the gas supply line feeding the water heater to permit servicing of the water heater. Compounds used on the threaded joints of the gas piping must be resistant to the action of liquefied petroleum gases/propane gas. DO NOT apply pipe dope to the gas valve inlet and make certain that no pipe dope has become lodged in the inlet screen of the gas valve. Extreme care must be taken to ensure no pipe dope enters the gas valve. Avoid excessive torque
when tightening the gas supply line to the gas valve. Excessive torque may result in cracking of the gas valve housing and could create a gas leak. The suggested maximum torque is 31.5 ft. lbs. (4.4 kg-m).

[Robert J. OConnor]

Sediment traps and drip legs are actually two different things.

Sediment traps (also called dirt legs) are primarily to catch debris that may be inside the piping, and needs to be installed as close as practical to the equipment after the supply shut off valve (IRC G2419.4 Sediment Trap). All the pictures appear to show the required sediment traps.

Drip legs are installed to catch moisture that may be in the gas if the local authority consideres the gas to be "wet", and must be installed at the lowest point in the gas piping where condensate could collect (IRC G2419.2 Drips).


Many times the sediment trap and drip leg are the same thing (and the terms interchangeable) because it is both the lowest point in the piping and just before the equipment ... as in this picture ...





In the following picture it appears that both a drip leg (on the left just as the pipe comes thru the wall) and a sediment trap (right at the equipment) are installed.

[Joseph W. Keresztury]

Here is an email image sent to me by a member, showing the drip leg/sediment trap before flex line as required by IRC. Everyone here agrees the drip leg/sediment trap should be as close to the WH gas valve as possible, which is true. But taking in consideration of the loop of the gas flex line, my opinion is that it should be before the flex line, changing the requirements and opinions of the drip leg/ sediment trap on a stiff (non flex) gas line that should be right before the gas valve of the Water Heater. Does this make sense?

[Robert J. OConnor]

Originally Posted by jkeresztury

But taking in consideration of the loop of the gas flex line, my opinion is that it should be before the flex line ...

Sediment build-up from the flexible connector between the hard pipe and the gas valve isn't a significant concern, so what is shown in the diagram is adequate.

[David Hays]

Here is one that is incorrect.

[Jeffrey R. Jonas]

Originally Posted by dhays

Here is one that is incorrect.

Attachment 46401

Hate to be standing next to that TPRV when she blows!

[bdoles2]

Another illustration

[Joe Funderburk, CMI]

This Joe agrees with Joe also.

Either way is fine. Pick another battle. The direction of the leg (will sediment blow into it or blow past it) and the fact that it is after the shut-off valve are of primary importance. Whether it's before or after the connector is of little consequence.