Before you call for service …
There are many minor problems that you can easily fix yourself. If your water heater isn’t working properly, look for the problem you’re experiencing on this chart and see if it’s a do-it-yourself job.
| Residential Electric Water Heater | ||
| Problem | Possible Causes | What to Do |
| No Hot Water | Manual switch turned off | Turn to ON |
| Blown fuse at breaker | Replace or reset | |
| High limit switch tripped | Manually reset ECO button | |
| Upper thermostat defective | Check and replace | |
| Upper element defective | Check and replace | |
| Grounded thermostat | Check and replace | |
| Thermostat out of calibration | Check, tighten and replace | |
| Improper wiring - Shorted or loose wiring Undersized service wire | Check and replace | |
| Not Enough Hot Water | Thermostat set too low | Increase thermostat setting not to exceed 120 degrees |
| Defective lower element | Check and replace | |
| Defective lower thermostat or miswired thermostat | Check and replace | |
| Improper wiring | Rewire per wiring diagram | |
| Loose wiring | Check and tighten | |
| Improper heating elements | Check wattage and replace | |
| Scale formation on heating element | Check elements; clean or replace | |
| Thermostat not flush with tank | Position thermostat so back touches the tank | |
| Poor grounding of tank | Check grounding and tighten | |
| Heater is undersized | Resize residence and compare | |
| Damaged dip tube | Check and replace | |
| Water Too Hot | Thermostat setting too high | Lower thermostat setting |
| Thermostat out of calibration | Check and replace | |
| Thermostat not flush with tank | Position thermostat so back touches the tank | |
| Grounded element | Check and replace | |
| Slow hot Water | Heating elements too small | Check wattage and replace |
| Lower thermostat is defective | Check lower thermostat and replace | |
| Noisy heating element | Scale build-up on elements | Remove, clean or replace |
| High watt density elements in the heater | Install low watt density elements | |
| Excessive relief valve operation | Excessive water pressure | Install proper pressure reducing valve on cold side Check for open or closed system. Replace T&P valve and install thermal expansion tank. |
| Excessive temperature | Check thermostat; lower setting or replace; check for grounded element. | |
| Rusty or black water | Scale formation on elements | Clean or replace elements |
| Anode rod dissolved | Check anode rod and replace | |
| Excessive sediment build-up | Try to drain tank; replace tank if sediment build up is excessive | |
| Water heater is leaking | Cold in or hot out joints | Check joint and repair |
| T&P valve | Check valve and replace Caution: Do not confuse normal T&P operation as a leaking tank. If the puddle dries up, then look for a T&P problem. | |
| Heating elements, anode rod and gaskets | Check, tighten and replace | |
| Inner tank has a pin hole | Replace water heater When diagnosing a leaker – you will notice a puddle of water on the floor, next to the heater, that will not go away. | |
| Smelly water (rotten egg odor) | Bacteria formation inside water tank | Clean tank using chlorine bleach Replace anode rod if deteriorated Add automatic chlorine feeder to cold water inlet side of tank |
| Milky water | Aerated water | Allow a glass of hot water to set for a few minutes. If the water turns clear, the condition is a natural occurrence |
| Residential Gas Water Heater | ||
| Problem | Possible Causes | What to Do |
| No Hot Water | Gas supply turned off | Turn on gas supply |
| Pilot not lit | See Unable to light pilot and Pilot does not stay lit | |
| Not Enough Hot Water | Thermostat set too low | Adjust thermostat |
| Burner orifice is clogged | Inspect and clean | |
| Low gas pressure | Check gas supply pressure and manifold pressure | |
| Venting downdraft (or other improper draft) | Check for proper up draft venting. Check for other drafts that could blow out the pilot light. | |
| Clogged flue | Inspect and clean flue way | |
| Defective thermostat | Replace gas control valve | |
| Defective dip tube | Check and replace dip tube | |
| Heater is undersized | Adjust Peak Hour Demand | |
| Unable to light pilot | Gas supply turned off | Turn on gas supply |
| Gas cock knob dial not positioned correctly | Check lighting instructions. Set control knob | |
| Defective thermocouple | Check and replace thermocouple | |
| Defective safety magnet assembly | Check and replace gas valve | |
| Pilot burner orifice clogged | Clean or replace | |
| Pilot tube pinched or clogged | Clean, repair or replace | |
| Poor thermocouple connection | Check and tighten | |
| Air in gas line | Purge air from gas line | |
| Thermostat’s single use ECO is tripped | Check ECO and replace gas valve | |
| Gas valve defective | Check gas valve | |
| Pilot does not stay lit | Poor thermocouple connection | Tighten connection at gas valve |
| Thermocouple defective | Check thermocouple and replace | |
| Thermocouple not in pilot flame | Move tip of thermocouple so it is immersed in pilot flame | |
| Defective safety magnet assembly | Check magnet and replace gas valve | |
| Venting downdraft (or other improper draft) | Check for proper up draft venting. Check for other drafts that could blow out the pilot light | |
| Clogged flue | Inspect and clean flue way | |
| Pilot partially clogged | Inspect and clean supply tube and pilot burner | |
| Improper gas pressure | Check and adjust supply side | |
| Main burner will not stay lit | Low gas pressure | Check gas supply pressure |
| Main burner orifice clogged | Clean or replace | |
| Main burner supply tube clogged or pinched | Clean, repair or replace | |
| Defective magnet assembly | Check and replace gas control valve | |
| Defective thermocouple | Check and replace | |
| Poor thermocouple connection | Inspect and tighten | |
| Defective main valve | Replace gas control valve | |
| Improper venting | Check venting for proper sizing and down drafts | |
| Scale on burner and pilot assemblies | Condensation | Excessive condensation caused by undersized heater, poor venting or continued use |
| Contaminated atmosphere | Check for contaminant causing chemicals near the heater | |
| Sooting | Combustion air inlets or flueway is restricted | Remove obstruction or debris from heater or flueway |
| Not enough combustion or ventilation air supplied to room | Improve combustion air or ventilation air supply | |
| Improper gas pressure | Check and adjust | |
| Burner orifice dirty | Inspect and clean | |
| Yellow flame | Scale on top of burner | Shut off heater; allow to cool; clean burner plate |
| Burner orifice dirty | Inspect and clean | |
| Flue way clogged | Inspect and clean | |
| Improper gas pressure | Check and adjust | |
| Burner flame noisy (whistling) | Improper gas pressure | Check and adjust |
| Burner orifice dirty | Inspect and clean | |
| Burner flame floats | Improper gas pressure | Check and adjust |
| Wrong orifice | Install correct orifice | |
| Clogged flue | Inspect and clean flue way | |
| Burner flame too high | Improper gas pressure | Check and adjust |
| Wrong orifice | Install correct orifice | |
| Water too hot (follow by pilot outage) | Thermostat setting too high | Adjust thermostat to lower setting |
| Thermostat out of calibration | Check and replace thermostat | |
| Slow hot water recovery | Burner orifice clogged | Check and clean |
| Excessive drafts | Locate and eliminate drafts | |
| Clogged flue | Clean flue chamber | |
| Improper gas pressure | Check and adjust | |
| Noisy water heater (rumbling and sizzling) | Scale or sediment build up in bottom of tank | Clean tank |
| Baffles loose | Reset and tighten | |
| Condensation on main burner | Inspect for condensation (normal) and tank leaks | |
| Excessive relief valve operation | Excessive water pressure | Install proper pressure reducing valve on cold side Check for open or closed system. Install expansion tank. |
| Excessive temperature | Check thermostat; lower setting or replace | |
| Rusty or black water | Anode rod dissolved | Check anode rod and replace |
| Excessive sediment build-up | Drain tank; replace tank if sediment build up is excessive | |
| Water heater is leaking (Gas water heaters produce condensation that may drip on the floor. Condensation will produce only a few drips or small puddles that evaporate.) | Cold in or hot out joints | Check joint and repair |
| T&P valve | Check valve and replace Caution: Do not confuse normal T&P operation as a leaking tank. If the puddle dries up, then look for a T&P problem. | |
| Immersion thermostat or anode rod is loose | Check, tighten and replace | |
| Inner tank has a pin hole | Replace water heater (When diagnosing a leaker – you will notice a puddle of water on the floor, next to the heater, that will not go away | |