Gas Water Heater Troubleshooting

Follow the gas hot water heater troubleshooting guide below to solve your gas water heater problem.

If you don't feel confident to preform a gas hot water heater repair this guide can give you a good idea of what's wrong with your gas water heater before the water heater repairman arrives.


This troubleshooting guide is for tank type residential water heaters.

Were looking for electric water heater troubleshooting.

Problems common to both electric and gas water heaters.

You will find links at the end of this guide to help you with testing and replacing water heater parts.


The probable causes are listed from most likely to least likely.


No Hot Water

1. Pilot not lit --- the most common gas water heater problem-follow the link at the bottom of this page for help.

2. Gas off --- check gas cut off valve at heater - check gas meter or gas tank.


Pilot Will Not Light

1. Gas off --- check cut off valve - check meter or gas tank.

2. Air in gas line --- hold pilot button down and try to relight several times.

3. Pilot orifice clogged --- remove and clean.

4. Pilot supply line kinked or clogged --- inspect - replace.

5. Defective gas control valve --- replace gas valve.


Pilot Lights But Will Not Stay Lit

1. Check thermocouple --- tip of the thermocouple probe must be in the pilot flame --- thermocouple must be tight at the gas control valve --- check thermocouple for kinks --- replace thermocouple.

2. Gas control valve defective --- gas valves can not be repaired --- replace gas control valve.


Pilot Light Goes Out Intermittently

1. Thermocouple going bad --- replace thermocouple.

2. Pilot orifice or line partially clogged --- remove and clean.

3. Main burner --- burner partially clogged causing blow back or roll out blowing out pilot light - Remove burner assembly and clean.

4. Down draft from flue --- this may happen on very windy days.

5. Gas control valve going bad --- replace gas valve.


Water To Hot

1. Short cycling --- this happens when you run just enough hot water to cause the burner to come on, by the time it cycles off the water in the top of the tank can be 20 to 30 degrees higher than normal.

2. Thermostat set to high --- adjust thermostat.

3. Gas control valve malfunction --- replace gas control valve.


Not Enough Hot Water

1. Thermostat --- adjust thermostat

2. Overuse --- You will only get around 50 percent of the water heater volume of really hot water - around 20 percent more warm water - Its very easy to use up hot water without realizing it.

3. Water heater undersized --- space out hot water usage - replace water heater

4. Thermostat malfunction --- replace gas control valve.

5. Burner orifice --- orifice partially clogged - remove and clean.

6. Water heater dip tube --- remove dip tub and check for cracks or breakage.

7. Low gas pressure --- call gas supplier.


Water Heater Slow To Reheat

1. Thermostat --- thermostat set to low.

2. Sediment --- extreme amount of sediment in bottom of the tank - drain, flush and clean water heater.

3. Burner orifice --- orifice clogged - remove and clean.

4. Weather --- incoming water temperatures may drop as much as 25 degrees in the winter.

5. Low gas pressure --- call gas supplier.


Water Heater Noisy

1. Sediment --- clean sediment from bottom of tank.

2. Heat traps --- heat trap nipples will cause a small amount of noise - this is normal.


Flame Rolls Out Of Access Opening When Burner Fires

1. Burner clogged --- remove burner assembly and clean burner and orifice.

2. Excess gas pressure --- call gas supplier.


Below you'll find testing and repair guides to compliment this water heater troubleshooting guide. More repair guides coming soon.

Temperature - How to adjust the water heater temperature.

Pilot light - How to light a pilot light.

Thermocouple - Check and replace a thermocouple.

Flush - How to flush sediment from your water heater.

Cleaning - Clean your water heater without chemicals.

This gas hot water heater troubleshooting guide brought to you by water- heater-repair-guide.com





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