Gas Water Heater Repair Tips

Water Heaters Are Pretty Expensive

Your water heater is one of the single most expensive components of your plumbing system.  It costs a lot of money to buy it and it costs more money to operate it.

If your water heater isn’t working properly it can make your life miserable.  Unless you really like cold showers it is a big deal when your water heater has problems.

Consider Calling A Plumber

This is a good time to talk a little about when it is appropriate for you to fix things yourself and when you should probably go ahead and call a plumber.  Water heater problems are a good example of when this choice is important.

If you water heater itself is leaking, as opposed to the piping connected to it leaking, this probably means that it needs to be replaced.  It is virtually impossible to repair a leaking hot water heater.  If you can’t confidently say you know how to install a water heater you really need to use caution.

A water heater replacement raises a lot of safety concerns and there are some fairly technical skills needed to do the job right. It is usually better to call a licensed plumber if yours needs replacing.  Licensed plumbers know how to install a gas water heater without creating a potentially dangerous situation (and how to install electric water heater without getting electrocuted in the process).

If It’s Not Leaking You Might Be Able To Fix It
On the other hand, if you have a non-leaking water heater and no hot water, you can often correct that yourself without calling a plumber.  You don’t need any really technical skills to learn to troubleshoot water heaters, just a little common sense and patience.

The first good news is that, although the trend is toward more economical water heaters, the basic operation and controls haven’t changed much over the years.  So some basic knowledge will allow you to troubleshoot water heaters of almost any age or manufacturer.

Gas Water Heaters

There are two main kinds of storage water heaters (we won’t get into tankless right now): gas and electric.  We’re going to focus on gas this time.

Gas water heaters use natural gas (and sometimes LP) to fuel a burner which in turn heats the water sort of like a pot on the stove.  They have only a few components that control whether or not you have hot water.

The first thing to check if you have a gas water heater and no hot water is whether or not you have gas.  I know it my sound silly, but I have gone to many homes only to find that the gas had been turned off for one reason or another.  If you have a gas stove see if it works.  If not, check your meter to make sure it’s on.

The Pilot Light

If you have gas, the next step is to check your pilot light and, if it’s out, try to light it. The lighting instructions are usually right on the water heater.  If your gas has been off it may take a while for the air to bleed out and the gas to get to the pilot, so be patient.

If your pilot won’t light, or won’t stay lit, the thermocouple may be the problem.  This looks like a copper wire coming from the control box on front of the water heater and going down to where the pilot light should be.  It has an enlarged tip at the pilot end.

The Thermocouple

The thermocouple is positioned with it’s enlarged end in the flame of the pilot.  This heat from the pilot flame causes a tiny electrical signal to be sent to the control valve, telling the control valve that there is a flame present so it’s OK to let the gas through to the main burner when it the thermostat calls for heat.  You can change a thermocouple on most water heaters with only a small adjustable wrench.   Just make sure that the bulb end is securely positioned in the pilot flame.  You can get a new thermocouple at most hardware stores for under $20.  This will usually correct a pilot light problem.

On more recent water heaters, the combustion chamber may be sealed.  If you have one of these there will usually be a small inspection window you can look through to check the pilot.  You may need to call the manufacturer to get a complete pilot assembly and new cover seal in order to repair these models, but the procedure is still pretty much the same once you get the parts. These parts are usually covered by the manufacturers warranty.

The Gas Control Valve

If you are sure you have gas, and replacing the thermocouple doesn’t fix the problem, the gas control valve is about the only thing left to check.  This is a fairly major repair so if you aren’t very comfortable working with gas connections you may want to call a licensed plumber for this.

If You Aren’t Sure, Call A Professional

Learning how to troubleshoot water heaters can be fairly simple but you do need to understand and be comfortable working with gas and understand venting.  Either one can literally kill you if you fail to observe the proper safety precautions.  If you aren’t qualified or aren’t sure about something it is better to be safe than sorry.

This article is for information purposes only and in no way should be interpreted as an encouragement to attempt any repairs for which you are not qualified.

Copyright 2008 Bryan Stevens

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1 comment to Gas Water Heater Repair Tips

  • Phil Loken

    The replacement gas control valve for a Sears Power Miser water heater has a plastic sleeve over the temperature probe. I expect this needs to be removed before installing. Is this correct?

    Thank you.

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