Are you looking for help with projects around the house? Our blog offers helpful tips and DIY videos, or schedule a service appointment today.

Common issues with a water heater and self diagnostics


Hi, this is Chris from John C. Flood. And today, we're going to go over some common issues and possible repairs that you may need to be informed on your water heater. Now, I know it's blazing hot outside. So the last thing you probably have on your mind is anything that generates heat. But alas, you still need that hot water heater of yours to function. So we're going to go over seven common issues that you may be faced with your water heater. One would be no hot water; two, inadequate hot water; three, rust-colored water; four, rotten egg odor; five, low rumbling or popping noise; six, higher-pitched whining; or seven, water leaking around the base of the heater.

Now, before you begin troubleshooting, you want to make sure you turn off the power to your electric water heater. Do this by turning off the circuit breaker or fuse powering the heater. Now, if you have a gas heater, turn the gas power control valve to the pilot setting. And lastly, shut off the water supply to the heater.

Okay, the first possible issue, you have no hot water. Some possible causes could be a faulty gas pilot, a faulty gas thermocouple, faulty gas pilot control valve, faulty electric thermostat, or a faulty upper electric heating element. Now, some possible repairs you might be faced with, so the first thing you can do is check the gas pilot flame and pilot operation. If the small flame is not visible, then it's out, and it'll need to be relit. Retighten, reposition, or replace the gas thermocouple. Replace the gas pilot control valve. And you can confirm power is being provided to the electric water heater thermostat. If the power is being provided to the thermostat, you maybe replace the thermostat or the heating element.

Next possible problem you might face is you have inadequate hot water. Now, some possible causes for that would be the unit is not large enough to meet your water heating demands or a broken or damaged dip tube allowing cold and hot water to mix in the tank, faulty plumbing installation that is crossing the cold and hot water connections, a gas supply or control problem, faulty electric lower or upper heating element or high or low heating element thermostat. A constant supply of lukewarm water during a shower is indicative of a defective upper heating element. Short duration of hot water supply during a shower is indicative of a defective lower heating element.

Now, some possible repairs you might be faced with and some things you can check. Make sure your water heater is not being overtaxed by hot water supply demands. The water heater should have 75% of its capacity as hot water. And that could be a 40 gallon water tank or water heater should be used for a demand of 30 gallons. Undo cold water inlet and pipe nipple and remove the dip tube. Check the condition or replace it if required. Check for cross connection by turning off the water supply to the heater. Open the hot water tap at the faucet. If there is water flow, then a cross connection exists somewhere. Check for a hot water line connected to a cold water connection on the water heater or appliances such as a washer, dishwasher, faucet, or shower valves. Check for proper flame from the burner. A natural gas flame should be a bright blue with the tip of the flame having just a tinge of yellow. A propane flame should have a blueish-green flame with a tinge of yellow at the tip. Check for power and electrical continuity at the lower and upper heating elements. Replace water heating element if necessary. Clear tank of any sediment that may have built up. And if the elements test okay, check the power at the upper electrical, upper thermostat. If it's okay, check the lower thermostat and replace if necessary.

Another issue would be rust-colored water. Now, some possible causes for that would be corrosion is occurring inside the glass-lined tank. Sacrificial anode rod is failing. Anode rods dissolve slowly to prevent rusting in the tank. Some possible repairs that would be needed here would be replace the sacrificial anode rod with a magnesium anode rod. Anode rods are available from a plumbing supply house. So you can probably find that wherever you can purchase plumbing supplies.

Another possible issue you may have would be a rotten egg smell. Now, this isn't fun at all. A possible cause for that would be bacteria in the tank sediment bed from hydrogen gas created from decay of the sacrificial anode. Now, possible repairs for this would be flush your hot water heater. Using a hydrogen peroxide solution of two pints, 3% peroxide to 40 gallons of water, [inaudible 00:04:50] tank and run some of the solution into the water lines. Let the peroxide solution set in the tank and pipe for two hours. The solution is not toxic and requires no rinsing. If problems persist, replace anode with a zinc alloyed node. If problems still remain, replace the water heater with a plastic-lined tank type.

Now, another possible issue would be low rumbling or popping noise. Some possible causes for this would be if you hear a boiling water noise, this would occur due to excessive build-up of sediment in the bottom of the tank, which is causing the tank bottom to overheat, and subsequently, the water will boil. Now, possible repairs for this would be remove the sediment by flushing the hot water heater. And traditionally, this will solve the issue.

Next would be higher-pitched whining. And this would be associated with an electric water heater. Some possible causes would be build-up of scale material on electrical heating elements. So you want to go and probably check your heating element co-, and make sure that there's no build-up on there and replace if necessary.

Now, lastly, water leak around the base of your heater. Possible causes for that would be a faulty T&P, which would be temperature and pressure relief valve. Now, the temperature and pressure relief valve leak due to excessive pressure, overheating, or it could be stuck. Leak from overhead or nearby plumbing connection or leaking water tank, corrosion would likely be the suspect here. Now, possible repairs and things you can check. Place a bucket under the overflow pipe. Open and flush the T&P valve clear of any debris. If the leak remains from the valve, you will need to replace this valve. Reduce the thermostat setting to prevent tank overheating and opening the T&P relief valve. Inspect the bottom of the tank by looking through the combustion chamber. If the water marks are heavy, rusting is visible. Or if the water is noticed in the bottom or if you see water in the bottom of the chamber, then your water heater needs to be replaced. Not always the best thing to hear, but those are some issues that you will have to deal with.

Now, obviously these are all possible causes and possible repairs. Not all of these may exist in your situation, but some things to check. If any of these situations, these issues are occurring and if you need any further help beyond what you've checked or are capable of checking, then give someone at John C. Flood a call, and one of our service technicians will be happy to come out and take care of that for you. Thanks so much.