If your hot shower isn't hot for very long anymore, one possible cause is a broken dip tube. A dip tube is used on top fed water heaters to carry the cold water to the bottom of the tank. If the dip tube should break (a common problem for heaters made in the 1990's), the cold water will enter the tank closer to the top; where the hot water leaves the tank, which will prevent the heating elements from having sufficient time to heat the water.
Symptoms of a defective dip tube
- Limited supply of hot water(could also be a thermostatelement problem)
- Plastic pieces clogging aerators and filters
- Manufactured between 1993-1997, a defective batch of dip tubes were installed on nearly every water heater and were prone to failure.
Replacing the dip tube
- Turn off the power to the water heater at the breaker.
- Close the cold water supply valve to the tank.
- Attach a garden hose to the drain at the bottom of the water heater and run it to a floor drain or sump pit.
- Open a hot water faucet to allow the tank to drain and leave it open.
- You will now have to remove the cold water supply to the tank and remove the nipple(short galvanized pipe), and remove the old dip tube carefully as it may crumble and fall into the tank.
- Replace with a new PEX dip tube and reconnect the cold supply. Replacements often come "one size fits all" and may need to be cut to size, about 6" from the bottom of the tank should be fine.
- If pieces were missing or fell into the water heater while you were removing the old dip tube you should flush out as much as possible from the drain on the bottom of the tank.
- This may be a good time to check the condition and replace the anode rod if required as well.