Comprehensive Guide to Hot Water Heater Troubleshooting

In our previous post, we gave you a quick preview to common problems and repair tips – from erratic temperature to no water produced, irritating sound emission and foul water odor to low pressure and water tank leaking. This time, we will give you the most comprehensive guide to hot water heater troubleshooting.
Your hot water tank is probably one of the most expensive components of your plumbing system. It costs a lot to buy it, it costs a lot to install and operate, and a replacement will further multiply the expense. Which is why, as much as possible, if your hot water tank is having some minor troubles, don’t head right away to the nearest store. You might have the perfect solution right in front of you. So read on.

There are two primary kinds of storage water heater: gas and electric. Both use insulated steel storage tank jacket with insulation located between the storage tank and the tank jacket that works to reduce heat loss of the heated water. In an electric heater, upper and lower heating elements are used to heat water and gas burner for gas. Electric or gas heater, these appliances are indispensable to most homes with colder climate.

NOTE: Before planning to troubleshoot, make sure to prepare safely by shutting off power to the electric heater. Turn off the circuit breaker or fuse for both electric and gas. Set the gas pilot control valve to “pilot” setting then shut off water supply. Hang warning signs to alert other family members you’re working with electricity-conductor device.

Here are some problems and repairs you can try:

No Hot Water

* Potential Problem

  • Circuit breaker was tripped or fuse handling water heater was blown hence heating elements are off.
  • Electric thermostat or upper electric heating element is broken.
  • Faulty gas pilot, thermocouple and pilot control valve for gas heater.

* Repair Tips:

  • Reset circuit breaker and replace blown fuse immediately.
  • Check if electricity is provided to the heating elements.
  • Replace upper heating element if it is not working.
  • Replace faulty thermostat or heating element.
  • For gas, check gas pilot flame and operation. Reposition and tighten gas thermocouple or replace if necessary. Also replace gas pilot valve if needed.

Not Enough Hot Water

* Potential Problem

  • Too much demand for heated water from an undersized device.
  • Dip tube is damaged causing cold and hot water to mix inside the tank.
  • Crossed cold and hot water connection due to improper installation.
  • Problems in the electric lower and upper heating elements thermostat. Lukewarm shower indicates defective upper heating element while short duration of hot water supply indicates defective lower heating element.

* Repair Tips:

  • Check unit capacity against demand for heated water. The heating device should have 75% hot water capacity.
  • Turn off water supply to hot water tank to check for crossed connection. Open the hot water faucet. If water flows out, then crossed connection lies somewhere in the device.
  • Check electrical power continuity in both lower and upper heating elements and thermostat. If necessary, replace any or all of them.
  • For gas, check water inlet and pipe nipple then remove dip tube. Replace if necessary.
  • Check burner for proper flame. Natural gas flame should have a bright blue color with a yellow tinge at the tip of the flame. Propane flame has a bluish green flame and a tinge of yellow at the tip.

Too Hot Water Temperature

* Potential Problem

  • Thermostat is set too high.

* Repair Tips:

  • Normal heating temperature is between 110-140 degrees F. Check both upper and lower heating element and reduce temperature.
  • If problem persists, replace thermostat.

Rust-colored or Yellowish Water

* Potential Problem

  • Corrosion, oxidization or deterioration inside the tank.
  • Sacrificial anode rod fails to dissolve to prevent rusting.

* Repair Tips:

  • Sacrificial anode rod must be replaced with magnesium anode rod.

Bad-smelling Water

* Potential Problem

  • Decay of sacrificial rod form hydrogen gas in the tank sediment where bacteria inhabit and feed from.

* Repair Tips:

  • Flush the water heater then treat tank with a hydrogen peroxide solution of 2 pints 3% peroxide to 40 gallons of water. Run the same solution into water pipes. Allow peroxide solution to sit for 2 hours. No rinsing required since solution is non-toxic.
  • If problem still remains, replace water heater with a plastic lined tank type.
  • If smell remains, a zinc alloy anode should be put in place of the old one. If problem not eliminated, a plastic lined water heater tank type is most desirable.

Rumbling and Whining Noise

* Potential Problem

  • Boiling water emits noise. When sediments build-up at the bottom of tank, it causes overheating hence boiling noise is heard.

* Repair Tips:

  • Flush water heater to remove sediments.
  • Remove scale and install low-density heating elements for heat to transfer to the water efficiently.

Water Leaks

* Potential Problem

  • Leaking overhead or other plumbing connections
  • Leaking loose bolts or bad gaskets
  • Leaking heater tank due to corrosion
  • T&P relief valve is defective. Overheating and excessive pressure could cause water heater leaking.

* Repair Tips:

  • Start by placing a bucket under overflow pipe then open and flush the T&P valve. Replace the T&P if leak continues from the valve.
  • A leak from the tank connection – in the water inlet or outlet or from the T&P valve would require tightening the connection using appropriate tool. Too tight can cause connection to snap.
  • Leak from heating elements needs tightening the element’s bolts. Turn off water and power to the water first. Do not over-tighten. Just snug enough to stop the leak. If leaking persists, remove heating elements and replace gasket.
  • Once the corroded storage tank is the source of the leak, you will have to replace your hot water tank unit.


Learning how to troubleshoot water heaters will come handy when you own one. However, safety precautions must be observed to prevent accidents that may cause injury or worse. If you are not qualified or confident of the task, then you’d better hire a professional to do the job for you.

This article does not encourage anyone to try their hands on water heater troubleshooting or attempt any repairs you are not qualified to do. It is always better safe than sorry so make sure you understand the job and the risks it entails.

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