Water Heater FAQ

My gas water heater runs out of water too quickly. What causes this?
In a gas water heater the usual culprit is mineral deposits on the bottom of the tank, primarily composed of lime and other minerals from local reservoirs. These deposits tend to insulate the water from the heat created by the gas burner, leading to very slow recovery. Also all storage type water heaters utilize a part known as a dip tube, whose job is to carry the incoming cold water to the bottom of the tank while the hot water is drawn off the top. These tubes tend to degrade over time, allowing cold water to be drawn into the hot water supply.

My electric water heater runs out of water too quickly. What causes this?
Again mineral deposits, this time on the heating elements. A defective element or thermostat will also cause this condition. Also electric water heaters have the same dip tube as gas models, and they fail in the same way.

Can I replace the dip tube?
That usually depends on the age of the heater. Dip tubes can be very difficult to replace in older heaters, and it's also not that cost effective in replacing a dip tube in a older heater whose tank will probably leak a few years later. If the heater is eight years old or newer it's a good option.

My heater doesn't work that well, it runs out of hot water quickly and by the sound of things, I'll probably eventually need a new one. But I don't want to do it now. What's the harm in trying to get a few more years out of this one and save some money?
The best way to save money is to avoid spending it, isn't it? Read on and I'll show you part of the reason why your utility bills take your breath away.
The problem in keeping old water heaters in service forever is that a ten year old water heater is on average, only 50% efficient. That means spending twice the amount of energy to supply a house with hot water than it needs to. As that hot water heating accounts for 14 to 25 percent of the average household's heating costs that amount of money is significant. Water heaters, except for the "on-demand" type, are not passive pieces of equipment, they re-heat numerous times during an average day, and again multiple times during the evening. Remember the old adage about the dripping faucet that added up to thousands of gallons a year?
Now let's do some quick calculations using the cost of energy in our area and see what the numbers tell us:
We'll start with an older natural gas 50 gallon heater that consumes 242 therms a year at 1.427 per therm which is what national Grid is currently charging, adding cost of delivery and fees.
242 x $1.427 = $345.34 (Annual operating cost)
But we have to double that figure since the heater is only operating at fifty percent efficiency.
$345.34 x 2 = $690.68 (Actual annual operating cost)
So our old water heater that we're keeping in operation to save money is now costing us seven hundred dollars a year to run, and if we keep it in operation an extra 3 years, we will have spent $1036.29 that we didn't have to.
Let's try this again with a 50 gallon electric water heater that consumes on average 4721 kWH per year at National Grid's price of $.1698 per kWH, again with taxes and fees included.
4721 x $.1698 = $801.64
Now we'll double that to account for the 50% loss in efficiency.
$801.64 x 2 = $1603.29
Now we're spending sixteen hundred dollars in electricity a year simply to have hot water, keep that heater in service an extra three years, and by doing so you'll spend an extra $2402.92.
Do you see the problem? Our water heater that we're keeping in order to save money is actually sending us to the poor house with it's voracious appetite for energy. But because it's always hidden in the monthly utility bill we simply pay the extra charges month after month, never aware of what that cost truly adds up to. And like the proverbial dripping faucet, it's at work 24 hours a day but it's natural gas or electricity going down the drain this time instead of water.

There's something coming out of the side of my heater and it's leaking.
It's called a "T&P" valve, which is short for temperature and pressure valve. It's job is to release excess water pressure due to thermal expansion and it's there to protect your water heater and plumbing system.

Now I know what it is, thanks, but why is it leaking?
If the T&P is leaking constantly, it's probably simply worn out and needs to be replaced. If the valve is opening intermittently, especially at night, that's usually an indication that the water pressure being delivered to the house is extremely high; the T&P opens at 150 lbs. per square inch. Water pressure this high puts an enormous strain on piping, water heaters, faucets, and toilets. You can solve this problem by putting a valve in your main supply line that regulates the pressure to your house and insulates it from potential damage.

My "T&P" is leaking, also my hot water is coming out scalding hot, how do I fix this?
The thermostat in your heater has failed, you need to shut it down immediately; this is a dangerous condition. If you can't do this yourself and don't have access to anyone knowledgeable enough then you need to call a professional immediately.

Both pipes coming out of my hot water heater are hot, the cold side more than the hot side. Is this indicative of a problem?
Not really. Remember that water expands when heated and since there's much less resistance on the cold water side, (it's connected to the municipal water system which is thousands of times larger than your household piping) so it will tend to move up that pipe first. You might want to insulate the cold water pipe though to stop that heat loss.

How do I drain my tank to flush out the sediment?
You'll need to hook up a garden hose to the drain valve at the bottom of the heater, and run it to a safe location. Most people make the mistake of trying to flush water heaters while the heater is under full street pressure, that merely blows the sediment around so that very little is flushed out. Turn the shutoff valve to your heater to where only a little water flows through. You'll only need to drain a few gallons to remove any sediment. Also be aware that if the valve has never been opened before, it may not shut completely off when you are done and may need repair. Also approach plastic drainage valves with extreme caution, these valves did not hold up well under water heating conditions, which is why few manufacturers still use them.

My pilot light keeps going out, why is this?
The usual cause of pilot failure in a conventional gas water heater is a thermocouple problem. Thermocouples sit directly in the pilot flame and supply a small amount of electricity, measured in millivolts, to the gas valve. This allows the gas valve to operate and also serves as a safety feature. If the pilot goes out, the thermocouple stops sending electricity to the gas valve, ensuring that it won't open up and send out gas that won't be ignited immediately. It's also important before replacing anything that you check for proper draft both at the draft hood and make sure that all passages that allow air into the combustion chamber of the water heater are free and clear.

But I've had the thermocouple changed, it still keeps happening.
At that point you'd look towards changing the gas valve. Be advised as well that there were a few models of gas water heaters sold at Lowes and elsewhere that had some major design flaws and were nearly impossible to keep running. These were built by American Water Heater and sold under a number of brand names. A gas valve going bad is extremely rare, the vast majority of the time they outlast the tank of the heater. So it's important to find out whether you have one of these defective models before installing a lot of parts in it.

My water heater has some sort of motor on top of it. What is this?
It's called a power vented water heater. The motor assembly is called a draft inducer, and it vents combustion product to the outside of the building without the use of a chimney. These water heaters came about as furnaces became more efficient and no longer used a chimney, they became power vented and vented through the wall of the home. At that point builders stopped building chimneys in new housing and the demand arose for a water heater that vented the same way. Power vents are also a great way to install a gas water heater in a house with no chimney, or where the chimney is unsuitable.

The motor is making a lot of noise, can I replace it?
Yes, but it's important to determine the age of the heater, as replacement draft inducers are fairly expensive. And when replacing an entire power vented water heater, they must be replaced with an appliance of the exact same type.

I have an electric water heater, and I'm getting almost no water from it. The water is plenty hot, but there's no pressure.
The usual culprit in this case is what's called a heat trap, they're installed in the dielectric fittings on both the hot and cold side of the water heater. The purpose of them was to stop heat migration up the pipes, even though the heat loss was minimal. The first renditions of these used little hard plastic balls inside them that were very susceptible to both trapping sediment as well as sticking in place. The modern ones use small rubber flaps so that isn't a problem any longer.
Heat traps more commonly fail on the hot water side of the heater. You can determine if that's the case by hooking a hose to the drain at the bottom of the heater, placing the end in a safe location, and opening the valve. If you have plenty of pressure inside the tank, then you know the problem is a heat trap located on the hot side. However, if you're going to take the tank out of service, it's advisable to change or remove the heat traps from both sides.

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