Importance of a gas line sediment trap

Have you noticed a short, vertical pipe sticking out from your gas heater or gas furnace that looks like it may not really have a purpose? That is what is called a gas line sediment trap, and it actually plays a very important role in keeping your gas-powered appliances operational. 

This short read will introduce you to everything you need to know about a gas line sediment trap.

What is it and why is it important?

Gas appliances tend to be very expensive, and it is only natural that you’d want them to last a long time. An important part of keeping them functioning flawlessly for years on years is to ensure that eternal debris does not enter the appliance and damage it.

This is exactly what a gas line sediment trap does. It keeps sediments and debris from entering the appliance. Sediment traps are also known as drip tees, drip legs, or dirt legs.

These traps also play a part in real estate transactions, especially home inspections while selling a house. If the home inspector notices that a gas-powered appliance that ought to have a trap is missing, it is likely to feature in the list of things expected to be addressed by the homeowner prior to closing the sale. However, it does not really have enough weightage to actually prevent the sale from going through.

Do all gas appliances need sediment traps?

State building codes generally dictate which gas appliances require sediment traps and which ones don’t.

However, in most cases, appliances that operate automatically, such as water heaters, as well as furnaces and pool gas heaters need to have them installed.

Appliances that have a visible flame when they are being operated do not need drip tees installed. This is because the user can easily notice when they are not working.

Examples of these types of appliances include illuminating appliances, ranges, clothes dryers, gas fireplaces, outdoor gas grills, and decorative vented appliances for gas fireplaces.

Installing a gas line sediment trap

If you have an appliance that requires a gas line sediment trap but does not have one, you could hire a plumber to install one for you for around $100. If you want to do it yourself, you could buy a DIY kit from the local hardware store for around $10.

Here are some key points to keep in mind while installing a drip tee.

1. The trap needs to be installed close to the inlet of the equipment.
2. It needs to be installed ahead of all pounds to inches pressure regulators.
3. The trap must be made of a tee fitting with a capped nipple and should be at least 3 inches in length.
4. The trap must have a 90-degree change of direction from the gas flow. This is to ensure that the sediments actually go into the trap and not into the appliance.
5. The cap should always be lower than the tee fitting. 

However, even here, there are laws that dictate how the trap shall be installed.

For example, in Florida, here’s what the building code states. 

“Where a sediment trap is not incorporated as part of the appliance, a sediment trap shall be installed downstream of the appliance shutoff valve as close to the inlet of the appliance as practical. The sediment trap shall be either a tee fitting having a capped nipple of any length installed vertically in the bottommost opening of the tee as illustrated in Figure 408.4 or another device approved as an effective sediment trap. Illuminating appliances, ranges, clothes dryers, decorative vented appliances for installation in vented fireplaces, gas fireplaces and outdoor grills need not be so equipped.”

Written by Narayan Shrouthy. December 26, 2022

Narayan is a content writer for Kukun. With experience in both content writing and editing, Narayan mixes his writing and love for reading with his passion for music. As an active musician, He aims to be a key player in Kukun's content experience.