Instructions on how to replace a water heater dip tube. How it works and how regular inspection can affect your heater's performance. How to diagnose a dip tube problem? Repair step-by-step guide.
The most common symptom of the broken dip tube is the lukewarm water when you are expecting hot.
A dip tube is the plastic pipe that delivers cold water from home plumbing to the water heater. It can be found only in tank-type heaters while it does not exist in tankless.
When looking at the top of the tank-type heater, either gas or electric type, you will notice two plumbing lines; incoming (with the blue ring) and outgoing pipe (with the red ring).
Note: Some water heaters with the cold water port located on side of tank do not have dip tubes.
The incoming line inside the water heater is actually a dip tube or cold water inlet extension. This system consists of the plastic tube and metal head, and it goes from the top of the heater, inside the water tank, and it ends only several inches from the bottom of the tank.
The cold water enters the water heater and gets heated either by the gas burner or heating elements. As the temperature of cold water increases, it rises to the top of the tank and from there it is drawn thru the hot water outlet to the fixture, shower or any other application. Every time hot water is drawn from the heater, it gets replaced with the cold water.
As explained before, a dip tube is used to bring the cold incoming
water from the home plumbing into the heater - lower part of the tank.
Some manufacturers use this plastic tube as a solution to the sediment
build-up problem. Specially designed tube utilizes ports to create
turbulent flow inside the heater's tank while preventing the deposits
on the heating elements and the bottom of the tank.
This advanced design can be found in Rheem and Ruud water heaters as the Everkleen system, Hydrojet in Bradford White and Dynaclean in AO Smith water heaters. This system is usually called the "self-cleaning system".
Inspection of the hot water heater dip tube and potential replacement should be done carefully. The dip tube can wear out, malfunction, disintegrate or even break. The first symptoms of the broken tube or incorrectly sized inlet tube are "no hot water", slow recovery and high operating costs. In such cases, cold water really enters the tank from the top of the unit, but doesn't reach the bottom part; it goes directly into the outlet pipe without being heated (it is diluting hot with cold water).
Another problem is associated with the material quality used for building these tubes. As the dip tube is being exposed to the water condition and chemistry including different temperatures, it might start falling apart where the small particles can affect the water flow. These pieces can clog strainers, filter screen, and aerators of the fixture or appliance that uses the hot water.
If you have a gas water heater, turn OFF the gas supply on the gas valve. If you have an electric water heater, turn off the breaker at the electrical panel.
Turn OFF the water supply to the heater. You can close the valve on the incoming water line or the main shut-off valve which is usually installed just above the water heater.
Use the garden hose and attach one end to the drain valve and other to the open drain. Before draining, open the nearby hot water faucet to vent the heater. Drain several gallons only (or below the inlet connection nipple), but be careful water might be hot.
To remove the dip tube you might have to cut the pipe.
Unscrew the dip tube and inlet nipple by using the pipe wrench and take it out. If dealing with the old heater you might use some help, such as WD-40 or any other substance for the rust.
Inspect the dip tube by looking for the cracks, obstructions, and any damage.
Install the new element and do not forget to put a Teflon tape on the threads, to prevent leaking, when the heater is full and works under pressure.
Note: Use the flexible hose connector to connect the plumbing and the dip tube (cold water inlet) as it makes the installation and future service easy.
As the dip tube is made of plastic and exposed to hot and cold water all the time, it is expected to see it malfunction. When the problem occurs you have two options; to call a plumber or do it by yourself. The guide from above shows how easy it is to remove and replace a dip tube. Either way, you go, the change will ensure great water heater performance and extend the life of a unit.