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Lead in the Water

(April 2004)

We've been hearing a lot about lead in the water in Washington, DC. Several people have asked me to talk about this subject as it relates to Virginia Hills. Here's what you should know.

Lead gets into the water supply in several ways. It can already be present in the water the water authority uses (usually where runoff from mines occurs). It can corrode into the water from the pipes and valves in the distribution system or from the pipes and fixtures in your house. Lead pipe was commonly used in water distribution lines and in the lines running from the distribution lines to houses up to about 1950. Solder containing lead was used to connect copper pipe until 1986. Faucets containing lead solder were available until the mid-1990s.

According to the EPA, lead's effects on humans include "interference with red blood cell chemistry, delays in normal physical and mental development in babies and young children, slight deficits in the attention span, hearing, and learning abilities of children, and slight increases in the blood pressure of some adults." Children and pregnant women should be careful to avoid water with high lead levels.

The U.S. Environmental Agency (EPA) has set the action Level for lead at 15 parts per billion (ppb) because EPA says, "given present technology and resources, this is the lowest level to which water systems can reasonably be required to control this contaminant should it occur in drinking water at their customers' home taps." By way of comparison, lead levels in the District have been reported at 50 to 300 ppb.

The problem in the District is due to lead distribution lines and possibly to a decontamination process which may accelerate the corrosion of lead into the water. Fairfax County, on the other hand, has no lead distribution lines, and the Water Authority (FCWA) has made an extensive effort to identify and replace any lead service connections in the older areas of its system.

As far as I know, all lines running from the mains to houses in Virginia Hills are made of copper. You can check this for yourself. Go out to where your water meter is at the street. Remove the cover and look at the pipes leading into and out from the meter itself. Use a bit of steel wool on them and they should brighten up to an easily identifiable copper color. A test that is almost as good is to look at the pipe running into the shutoff valve inside the house. Use the steel wool again if you're not sure. Lead will have a dull grey-silver color. If you do both tests, it's highly unlikely that lead pipe was spliced in between the meter and your shutoff.

Because Virginia Hills houses were built in the early 1950s, the solder holding the pipe and fittings together will contain lead. Faucets that are less than six years old or so probably contain lead. Since 1998, FCWA has been adding a corrosion inhibitor, zinc orthophosphate, to the water to help prevent lead corroding into the water. FCWA also adjusts the pH (a measure of acidity and alkalinity) of the water to minimize corrosion from household plumbing.

Here's the bottom line as reported by FCWA: "in 2002 (the last Lead and Copper Rule sampling period for the Water Authority), the 90th percentile value for lead was 2.1 parts per billion (ppb) compared to the EPA Action Level of 15 ppb." In other words, our water is well below the action level.

High lead levels in the blood are often caused by other problems. When many of us were growing up and gasoline contained lead, it was a major contributor. Ingesting lead paint or inhaling dust from sanding lead paint can also raise the lead levels. I wrote about lead paint in October 1994. You can read that article here.

To be 100% safe with your water, do the following:

1) before drinking tap water, let the cold water run until it turns cold, usually 60-90 seconds. That will flush out the water that has been sitting in your pipes.

2) Don't cook with hot water or use it for hot beverages. Use cold water that you've let run as in #1 above. The hot water has been sitting in the water heater and will therefore contain more minerals in general and more lead specifically.

If you would like your water tested, call FWCA's Customer Service Department at 703-698-5800. The charge for lead level testing of your home's water is $35.00 per faucet.

Copyright Doug Boulter, 2004

Heat Loss Calculations

(February/April 1999)

Part I

This month, out of curiosity, I was experimenting with heat loss calculations.  A heat loss calculation is a determination of how much heat your house will lose on the coldest day of the year.  Why would someone want to do the one?  First, if you were replacing your furnace, your heating contractor should do the calculation to insure he installs the right size unit.  Second, a heat loss calculation can tell you what energy saving measures you should undertake to improve your house.  I was surprised by some of the results I found doing the calculations.

Heating contractors will tell you that their clients often insist on furnaces that are too big for the house.  People assume that the bigger a furnace is, the better it will heat.  This is wrong!  A furnace that is too big for the house will not run efficiently.  It will heat the house quickly, which is good, but once the house is heated, the furnace will have to maintain that temperature, and there is where the problem arises.

When your furnace comes on, you notice that it doesn't start blowing hot air immediately.  That's because the burner must first warm up the heat exchanger so that the fan has hot air to blow through your ducts.  Of course all the energy that goes to warm up the heat exchanger is wasted -- it isn't heating up the air in your house, just that metal heat exchanger in the furnace.  To avoid this,  the furnace should come on again shortly after it shuts off and the heat exchanger is still warm.  If your furnace is too big, there are long periods when it is off and the heat exchanger gets cold.

An air conditioning system sized too large will produce a different problem.  As you know, your air conditioner is also a dehumidifier, taking the summer moisture out of the air.  If the air conditioning is too large, it won't run long enough to take much moisture out of the air and the house will feel cold and clammy.

A heat loss calculation is fairly complex, but I'll talk you through how it's generally done so you understand what your contractor is doing.  The first step is to determine the "Delta T."  This is the difference between the outside temperature on the coldest night of the year and the desired inside temperature.  In this area, Delta T is 70 degrees, an outside temperature of 0 degrees, and an inside temperature of 70 degrees.

From there, the next step is to determine the loss through ceilings, floors, walls, windows, and doors.  The contractor will find the square footage of each of these, divide by the R-value of your insulation or the R-value of the window or door, and multiply it by the Delta T.  The result is the heat loss in BTU/hr.  For example, let's say the insulation in your attic is the original four inch rock wool with an R-value of 12.  Your ceiling area is 900 square feet.  Delta T is 70.

900 / 12 x 70 =  4500 BTU per hour.

This gets added to the loss from windows, walls, and doors, all done in the same way.

Floor heat loss is calculated a bit differently.  Concrete slabs lose heat from their edges, so the calculation is based on the length of the perimeter rather than a square foot calculation.  If your basement is heated and entirely below ground, the floor loses only about 2 BTU per hour per square foot.  That's because the temperature of the ground below the frost line in this area is about 57 degrees.  Of course, losses for the walls and windows in the basement must be calculated as well if it is heated.

Finally, a factor is added for air leaks or "infiltration."  A house built or remodeled to current standards might need to add only 10% heat loss for infiltration, while an older house might need to add 30%.

Adding these together gives you an overall heat loss.  The new furnace will have to provide enough heat to make up that loss.  Your contractor should be able to recommend a furnace size based on this calculation.

Does it really make a big difference?  You bet it does!  I did the calculation for an original house, with its single pane casement windows, no insulation in the walls,  uninsulated wood doors, R-12 attic insulation, and a generally leaky construction would have needed a furnace producing 120,000 BTU.  As remodeled with R-15 walls, R-36 attic insulation, thermal pane windows, and insulated steel doors, it would need only a 60,000 BTU furnace.  The smaller furnace is more efficient AND costs less to buy.

In the next issue, we'll talk about the implications of this for making energy improvements, and how your contractor can use this information to size your heating ducts as well.

Part II

In my article in the last issue, I wrote about heat loss calculations that your contractor should perform to size your furnace and air conditioning systems.  This time we'll talk briefly about sizing heating ducts and discuss balancing your heating system.  Then we'll talk about the implications of heat loss calculations for energy saving improvements.

A good heating contractor can use the heat loss calculation for each room in the house to properly size the duct(s) for that room.  Unfortunately, at this stage in the game, unless you are doing a major renovation of the house, you probably won't be changing the size of your ducts.  What you can do, however, is to "balance" your duct work to improve the overall comfort level and avoid rooms that are too warm or too cold.

First, open each duct in your house as far as it will open.  Let the furnace run through several cycles.  Then, measure the temperature in each room.  Partially or completely close down the ducts in the warmest rooms and let the furnace run some more.  Measure the temperatures again.  Once more, close or partially close the ducts in the rooms that are now warmest.  The result should be a more even temperature throughout the house.

Of course once it becomes cooling season and you run your air conditioner, you will want to check the temperatures again and re-balance as necessary.

In the last issue, I compared the heat loss calculation for an original Virginia Hills house and the same house after it was remodeled.  As it turns out, the biggest energy savings came from insulating the walls.  The original house would lose 27,182 BTU per hour through the walls on the first floor, while, after insulating those walls to R-15, the loss is only 7,431 BTU.  This is a significant saving.

The problem with insulating walls is that it can't be easily done.  To insulate, you have only three choices.  You can have a contractor drill holes in the wall and blow in insulation.  You can tear out the drywall, insulate, and hang new drywall.  You can remove the siding and insulate from the outside.  Let's examine each of these options.

If you have a brick exterior, you certainly aren't going to be able to remove it to insulate.  If, however,  you have the old asbestos or newer vinyl or aluminum siding, you may want to replace it.  When the old siding comes down, you can also pull down the building paper and fiberboard that is under it and you'll have access to the stud bays where you would install insulation.  Add foil-faced insulating board to the outside, a vapor barrier, and replace the siding.  It's an expensive job, but probably the easiest way to get the insulation in the walls.

Tearing out the old drywall, insulating, and putting up new drywall can be done a room at a time.  Drywall work is not easy, however, and you can end up with a room or rooms that are out of service for a long time.  This and the previous method do have the advantage of giving you access to the stud bays not only for installing insulation, but also making any electrical upgrades you desire to make.

Having a contractor insulate your stud bays by cutting holes in the drywall is a standard fix, but due to the fire blocking in each of the stud bays, the contractor will have to make two holes for every 16" section of wall.  You are relying on the contractor's drywall patching abilities to make these holes invisible, and unless he does a good job, your walls may never look quite right again.

The next greatest energy saving comes from upgrading your windows, taking you from a loss of 12,645 BTU per hour to 5,033 BTU per hour.  Windows are an expensive upgrade, but there is a large gain in appearance as well as a savings in energy.

Surprisingly, replacing two old wood doors with insulated steel doors does almost as much as replacing all your windows, moving you from a loss of 9,240 BTU to 3,654 BTU per hour.

Finally, increasing the insulation in the ceiling from the existing R-12 to R-36 saves very little energy, despite the fact that it is often the most recommended method of saving energy.  The data suggests only a move from a loss of 4,940 BTU to loss of 1,976 BTU per hour.

These numbers suggest that there is no easy energy fix for Virginia Hills houses.  On the other hand, if you are doing work for other reasons such as adding on to the house or making cosmetic improvements, you can often attain energy saving at little additional cost.

Copyright Doug Boulter, 1999


(April 2013, updated from September 1997)

Get up in the morning, turn up the thermostat and freeze until the house warms up.  Go to work and turn it down to save energy.  Come home, turn it up, and freeze again until the house is warm.  Go to bed at night and turn it back down to save energy.  If this sounds familiar, you might want to consider a setback thermostat which will do all of the above automatically. While setback thermostats have been with us for over 30 years, a number of things have changed since I first wrote about them 15 years ago.

One change has to do with the heating system itself. Heating systems have gotten much more complex. A fairly recent change is the change on upper end systems from single stage to multistage. A single stage system has a single level of heating and cooling and a single speed fan. A multistage system may have three levels of heating and two of cooling. Instead of off-on, think high-medium-low (or high-low) and a variable speed fan. High end setback thermostats can handle this complexity. Low end ones can't.

Most setback thermostats can't handle electric baseboard heat, but many can manage electric or gas backup heat for heat pump systems.

In short, you'll need to know what kind of heating/cooling system you have to make sure your new thermostat will work with it. A good idea might be to call the manufacturer's hotline (they all have a hotline) to see if they think the thermostat you want will work with your system. And they can also talk you through the installation if you get stuck.

A second change involves the number of programs on setback thermostats. Thirteen years ago, your choice was every-day-the-same, or a 5-2 program if you wanted different program from the weekday program on Saturday and Sunday. Now, you can get a 5-1-1 program to allow different programs on Saturday and Sunday, or you can get a 7 day program to make each day different. Some, the Nest being the best known, will program itself as it learns your habits.

Most thermostats now come with a filter change reminder. The thermostat calculates how many hours the system has been running and, based on that, let you know when to change your furnace filter.

The latest thing, of course, is Wi-fi. If you have a wireless network at home, you can talk to your thermostat with a smartphone, laptop, or computer when you're away from home.

Of course, the more heating systems your thermostat serves, the more programming options it has, and having wi-fi will substantially increase the price. There are thermostats (the Nest being the most famous) that cost about $300. There are also some at a tenth that price.

Thermostats are easy to install if you follow the directions in the package. You will have to remove your old thermostat, mount a plate to the wall, and attach some wires. Removing the old 'stat is a matter of popping off the cover and removing some screws. Before you disconnect the wires be sure to write down the match between the letters by the screws and the wire colors. To mount the plate of the new 'stat, you will have to drill two holes in the wall, insert plastic screw anchors (provided with the new 'stat), and screw the plate on. Finally, you re-attach the wires exactly as they came off the old thermostat, maybe. Here's where reading the instructions is important or calling the help line if you're not sure what you're doing.

A setback thermostat can save you 33% on your heating and cooling bills. Well worth considering.

Copyright Doug Boulter, 2013

Gas Furnaces and Their Repair

(February 2013)

Gas furnaces are reliable and much less difficult (and much less expensive) to maintain and repair than an oil fired system. They're much less expensive to operate than electric resistance heating or a heat pump. Still, repairs can be costly, so it's helpful if you know how to maintain your system and can make obvious repairs yourself. To do this you need to understand how a gas furnace works. This article will mostly discuss furnaces that are under 90% efficient. While high efficiency condensing furnaces are similar, their problems are not identical.

Everything begins with the thermostat. When it's colder in the house (near the thermostat) than the set temperature, the thermostat calls for the furnace to heat the house. When that temperature is reached, or just a bit above that point, the thermostat tells the furnace to turn itself off.

Once the furnace receives the thermostat's on signal, most non-condensing furnaces start by creating a draft up the chimney. They do this for the same reason you create a draft in the chimney when you light a fire in a fireplace; if air isn't moving up the chimney, the smoke and invisible products of combustion, such as carbon monoxide, come back into the room and could kill you. The furnace uses a powerful fan to create and sustain the updraft.

Once the updraft exists, a sensor tells the furnace to light the burner. Fifteen years ago, this meant that the gas valve released gas in the vicinity of the standing pilot light which ignited it. To save energy, furnaces eliminated the pilot light that wasted gas and replaced it with an electronic spark igniter (you hear clicking when it's creating sparks) or a hot surface ignition that ignites the gas. If the burner doesn't quickly ignite, another sensor tells the gas valve to shut off the gas.

Once the burner has ignited, a different sensor measures the temperature in the heat exchanger. Until the heat exchanger warms up, this sensor won't let the fan start running because it would just blow cold air into the house and waste the heat being generated. If the heat exchanger gets too hot, a sensor will shut off the gas valve to stop combustion, as this would be dangerous.

When the heat exchanger is sufficiently warm, the blower will run and warm air will circulate to the registers in the house. When the thermostat determines that the house temperature has reached the desired level, it tells the furnace to shut down. Then the cycle begins again.

As you can imagine, the furnace is designed to fail if any of these sensors malfunctions. So if the furnace won't start or won't stay running, it's likely to be a sensor problem. Very few homeowners will want to replace sensors, circuit boards, or other parts and will want to call a repair person. However, before you make that call, there are some things you can check.

If the thermostat is malfunctioning, the furnace will never get the start command. Most thermostats these days are totally electronic and are powered by household batteries. If the thermostat information screen is blank, either the thermostat is off, in which case turn it on, or the batteries are dead, in which case change them.

If you are experienced and have the wiring diagram for the thermostat, you can essentially bypass the thermostat by jumping or touching the appropriate wires. If the furnace starts and keeps running until you stop touching the wires, the problem is the thermostat. However, I'm not giving you more information on how to do this because WARNING! touching the wrong wires can do some expensive damage.

Next, check your circuit breakers and ensure that the breaker for the furnace (not the air conditioning compressor) is on. Flip it off and back on to be sure.

There also should be a switch next to your furnace as an emergency shut off. It will look like a light switch and may have a red cover. Flip it off and on. If you have a multimeter, you can test to see if power is going through the switch. If it is, and the thermostat is ok, you likely have a sensor or electronic problem with the furnace.

Then check the gas shutoff on the pipe next to the furnace. Is it open? It should be, of course. It's worthwhile, however, to see if other gas appliances such as your stove will work to be sure that the gas supply to the house is still functioning.

If the furnace starts but won't stay running, check the filter. If it's so dirty that the airflow is seriously restricted, that may cause the heat exchanger to get too hot and the furnace will keep shutting itself down until it cools. A new filter will fix that.

If the blower in the furnace won't run at all, turn the fan switch on the thermostat to auto. If the fan runs, it's a sensor problem.

Copyright Doug Boulter, 2013


(September 1998)

This month, we're going to deal with a very mundane subject, the drains in Virginia Hills homes and how to maintain them.

Your may think of the plumbing in your home as a single system, but it really has two parts.  The supply system provides fresh, potable water.  The drain, waste, vent (DWV) system connects with the sewer to dispose of the fresh water that has been "used."  In Virginia Hills houses, the DWV system is composed of metal pipe, cast iron for the bigger waste pipes and vents and galvanized steel for the smaller ones.  Here is one place where old is good.  Cast iron today is used in very high end construction.  Plastic pipe, mostly PVC, is what is used in most houses.  On the down side for Virginia Hills homeowners, galvanized steel is almost never used these days because of its inherent problems.

PVC DWV pipe has several advantages over the other types.  First, it is very quick and easy to install.  You cut it with a hacksaw and glue it together.  Second, the inside of the pipe is very smooth and will not rust.  This means that the pipe's inside diameter will not get smaller over time because of a gradual buildup of rust and material from the sink that clings to the rust.  There is one major disadvantage to plastic pipe, and that is that it is noisy.  Flows of water through it are clearly audible, especially the flushing of a toilet.

Cast iron has the advantage of lasting almost forever and being very quiet.  Flushes are almost never heard.  The disadvantages of cast iron are its cost and, in the old days, the difficulty installing it.  Modern cast iron is now connected with special "no-hub" couplings, and is almost as easy to install as PVC.

Galvanized steel was used for drains under three inches in diameter, such as the drains from sinks, tubs, and showers.  Over the 45 years since it was installed in Virginia Hills, buildups have occurred inside the pipe, and these are the cause of most clogs today.   If you cut out a piece of 2 1/2" old pipe, you'll see that it has a diameter about the size of a penny or a dime.  Where hair or soap would never cause a problem in a clean pipe since it would easily go down the drain, it causes frequent blockages in pipes with such a reduced diameter.

The best way to clear such blockages is with a drain snake, a flexible piece of coiled wire with a larger head to clear the blockage.  Plumbers have power snakes, but hand snakes are inexpensive (under $10) and work well.  To snake a sink drain, remove the pop up stopper and push the snake down the drain while cranking on the handle.  You can only push a bit at a time, but your patience will be rewarded as the snake slowly goes through the drain.  You may have to go 12 to 15 feet to get to the clog (one reason why drain cleaning liquids often are ineffective).  If you are working on a bathtub drain, you can't get down through the drain hole.  Remove the overflow cover and go down through it.  Drains in old homes like ours may require snaking once a year or more.

Snaking a toilet requires a different type of snake called a closet augur.  It has a fixed curved piece at the end of it to get into the toilet's trap, and has a rubber covering to avoid scratching the visible parts of the toilet bowl.  A closet augur is also relatively inexpensive.

One other problem might cause a failure of a sink to drain, and that is a blocked vent on the roof.  The vent's function is to let air into the system to avoid a vacuum when the water rushes down a drain.  If a bird has nested on a vent, the system will be very slow to drain.  Often, a high pressure hose will clear any obstruction in a vent.

If your galvanized drains start to leak, replacement with PVC is usually the only option.  These smaller drains rarely make so much noise as to be troublesome, so PVC is an acceptable solution.  The larger cast iron pipes should not leak, except at the basement clean out where the threads might rust (a clean out is the access cover from which to get to your sewer outside the house).  Again, the best solution is replacement of the short clean out section with a PVC clean out.  I would strongly recommend against allowing horizontal runs of large PVC, however, as it will produce a great deal of unpleasant noise.  Burying PVC in insulation will cut down the noise somewhat, but you would be amazed at how much uninsulated PVC drain pipe is installed in the ceiling above dining rooms.

If I were building a house today, I would install no-hub cast iron for all my large drains and PVC for the small drains that feed into the large drains and the vents.

Copyright Doug Boulter, 1998

Should You Get Your Ducts Cleaned?

(April 2005)

You may see a number of offers to clean your heating /air conditioning ducts, and you may hear that you need your ducts cleaned for your health. Are these claims true? Should you get your ducts cleaned at a fairly substantial cost? In this article I'll summarize a report from the U.S. Environmental Protection Agency (EPA) as well as some other research, and I'll offer a tip or two to keep your indoor air clean and healthy.

The full EPA report can be seen on the web here.

How to Decide

The EPA says:

"If no one in your household suffers from allergies or unexplained symptoms or illnesses and if, after a visual inspection of the inside of the ducts, you see no indication that your air ducts are contaminated with large deposits of dust or mold (no musty odor or visible mold growth), having your air ducts cleaned is probably unnecessary. It is normal for the [air] return registers to get dusty as dust-laden air is pulled through the grate. This does not indicate that your air ducts are contaminated with heavy deposits of dust or debris; the registers can be easily vacuumed or removed and cleaned."

The fact is that, while all ducts get dirty, most of this dirt adheres to the surface of the duct and doesn't become airborne. If you've ever tried to scrub the dirty surface of the inside of a metal duct, standard in Virginia Hills homes, you know how hard it is to get that layer off. The only issue would be if mold were growing in the duct, which would only be likely to occur if water got into the duct space. While you might see dark spots on the inside of a duct, only a laboratory can determine if it is mold; most likely it won't be.

So when should you have ducts cleaned? Some few individuals with serious allergies might benefit from duct cleaning, although the cause of the allergy commonly comes from something outside the house (pollen, for example) or something that isn't in ducts (dust mites, found in carpets and beds) rather than something coming from the ducts. The EPA has published information for doctors about duct cleaning and recommends that you seek your doctor's advice before you spend money on cleaning your ducts to relieve allergy problems.

If you've just bought a smoker's house and you're a non-smoker, duct cleaning might be a part of your efforts to remove the smoke odors. If the previous owner had a lot of pets and you're allergic, a one-time cleaning might remove pet hair and dander from the ducts.

Finally, if you've had birds or animals, particularly mice, get into your ducts, a cleaning would be a good idea.

The bottom line is that duct cleaning is not needed as a periodic maintenance service for most people, and even after 50 years, there is no compelling need for most people to have their ducts cleaned.

What to Look for in a Duct Cleaner

Real duct cleaning will take four to eight hours and cost you $500-$1000, so it's not cheap. Duct cleaning firms that offer to clean your ducts for a few hundred dollars are either cutting some serious corners and/or will attempt to sell you very expensive add-on services.

Contractors who clean your ducts properly will put the system under negative pressure using a powerful vacuum and then insert various brushes to clean the inside of the ducts. The vacuum should exhaust outside or have a high-efficiency particle air (HEPA) filter on it. Otherwise, dirt that was inside the ducts and not causing a problem will be blown into your house where it might cause a problem–and increase your cleaning chores.

Duct cleaners may attempt to sell you on the value of using a chemical microbial agent on the inside of the ducts to kill bacteria and fungi. The EPA says that "there remains considerable controversy over the necessity and wisdom of introducing chemical biocides or ozone into the duct work. . . Little research has been conducted to demonstrate the effectiveness of most biocides and ozone when used inside ducts." The EPA goes on to note that "some people may react negatively to the biocide or ozone, causing adverse health reactions."

If you want cleaner air in your house, change your furnace filter at least twice a year; four times is better. Consider purchasing an electrostatic air cleaner to attach to your furnace. Vacuum your house regularly with a modern vacuum equipped with a HEPA filter.

Copyright Doug Boulter, 2005

Water Heater Maintenance

(June/September 2005)

Part I

No one thinks very much about their water heater unless it stops working. Then, we're reminded about just how much of a convenience hot water is. While new water heaters aren't very expensive to buy, they can be expensive to install, and being without hot water can be very inconvenient. In this article, we'll talk about how a few simple and inexpensive maintenance procedures can greatly extend the life of your hot water heater.

Safety First!

One of the biggest dangers of a gas-fired hot water heater is inadequate ventilation for combustion gases. This can be because the chimney wasn't installed properly, or because your house is tightly insulated and when the furnace kicks on, it needs so much combustion air that it causes a backdraft that pulls the products of water heater combustion into the house. A HVAC technician, chimney sweep, or plumber familiar with water heater installation can check this for you.

But to really be safe, as I've said before, you need a working carbon monoxide detector near your furnace and water heater. If you don't have one, get one!

If you're having constant problems with backdrafting, you may need to switch to an electric water heater.

Temperature and Pressure Relief Valve

The second danger for a hot water heater (gas or electric) is that if the heat doesn't shut off at the right time, it can boil the water in the heater, turning it to steam. At some point, the pressure build-up will be so great that the tank will explode with the force of a military bomb. Water heaters have been known to launch themselves through the floor above and through the floor above that.

To prevent this from happening, all modern water heaters are equipped with a temperature and pressure relief valve which senses the pressure and opens when it gets too great. You'll see this valve on the side of your tank toward the top, and it will have a pipe extending from it down to about 6" above the floor. If you see water on the floor under that pipe, it means one of two things: either your valve is doing its job and you need the water heater worked on right away, or, more likely, the valve has gone bad over time and needs to be replaced. It's about an $8.00 part, and you can replace it yourself.

Shut off the burner and the cold water line providing inflow into the heater, then drain enough water out of the heater so the level is below the valve. Using a wrench or a big pair of pump pliers, unscrew the extension pipe from the valve and remove the old one. Take the old valve to the home center or plumbing supply store with you when you go. There is a short valve and a longer one. You need to get the correct size. Install the new valve so that it is tight and the extension will point at the floor when it is screwed back in. Use teflon tape or pipe dope on the threads of the valve.

Ideally, you should test the valve a few times a year by pushing the lever on it to force it to release a burst of hot water. But be warned! If you haven't been doing this since the valve was new, testing it will likely start it leaking. If it's not a new valve, leave well enough alone.


Minerals in the water will precipitate out over time and form deposits on the bottom of the water heater. When water is heated, water trapped behind those deposits will be superheated and you'll hear a popping sound. While this is often diagnosed as the beginning of the end for the water heater, water heaters can last a very long time with sediment before the tank starts to leak.

You can prevent sediment build up with some simple maintenance. Every quarter or so, take a short length of garden hose and hook it to the end of the drain valve at the bottom of the heater. Put the other end in the floor drain. Shut off the burner or the electric heating elements, shut off the cold water inflow, and open the valve. To make the water heater drain fast, open several hot water faucets throughout the house to break the vacuum. Drain out about 10 gallons or so of water, less if the water runs clear.

Even on good water heaters, the drain valves are cheaply made and often break after a few uses. You may need to drain the heater entirely and replace that valve with a good one (which will only cost a few dollars too). Don't forget the teflon tape or pipe dope on the threads.

Next time, more maintenance and fixes for your water heater.

Part II

Standard water heaters haven't changed much over the years, except for additional insulation to improve energy efficiency. If you've purchased a water heater in the past ten years, there aren't many reasons to purchase a new one unless the old one starts leaking (and not from the temperature and pressure relief valve which you can replace). And you can make your water heater last for 20 or more years if you do some routine maintenance.


Both gas and electric water heaters have a metal rod or rods inside the tank called a sacrificial anode. Anodes literally give up their lives so the water heater can live. That's because the aluminum or magnesium anodes corrode away so that the minor amount of exposed steel inside the water tank won't. The warranty on any water heater is based on the number and quality of the anodes, because when they're gone, the steel starts to rust, and then the tank will leak. Soft or softened water will cause the anodes to corrode faster.

The good news is that you (if you're handy) or a plumber can replace the tank's anode very easily. They screw in the top of the tank. The problem most homeowners encounter is that there is limited ceiling height above the water heater. Needless to say, you can't install a 5' anode in a 5' high water heater if the ceiling is only 7'6" high. But not to worry. You can buy a flexible anode that will bend sufficiently to make it into the tank.

Magnesium protects better than aluminum, so you'd want to replace all the anodes with that, unless you have water with a bad odor. In that case, use aluminum, zinc, or a combination of aluminum/zinc. Manufacturers think a single rod should last about six years; two rods should last 12 years.

The problem is that a flexible anode may cost $100-$150. If you're paying a plumber to do the replacement, you're probably over $200 total for one rod. Depending on what you'd have to pay to have a new water heater installed, it may be worth it to replace the entire heater.

Dip Tube

The dip tube is a roughly 4' plastic or metal pipe that attaches to the water heater's cold water inlet and carries the cold water to the bottom of the heater where the burner or heating element is. If a dip tube cracks or breaks, incoming cold water will only slowly fall to the bottom of the heater. You'll feel a lack of hot water because the "hot" water flowing out the top of the heater will really be lukewarm at best.

The good news is that a dip tube isn't an expensive item. A plumber can replace it in 15-30 minutes. Other causes of too little hot water could be a bad thermostat, a burned out electric element in an electric water heater, or a teenage boy taking long showers. All of these are a bit more difficult to deal with.

Expansion Tank and Air Chambers

Heating water makes it expand. In a closed household system, that creates extra pressure, producing more strain on the weakest places, usually the faucets. If you've noticed that hot water faucets leak a lot, it may be due to the expansion of the hot water in your system.

One solution is to have an expansion tank installed. The tank allows the increased volume of hot water to expand into the tank. The water is released back into the water heater when a faucet is opened in the house.

However, many homes have air chambers installed to prevent water hammer (the pounding sound you hear when a faucet, washer, or dishwasher is turned on). These air chambers also allow space for the expansion of heated water, so an expansion tank may be overkill. However, over time the air in these chambers may be absorbed into the water. You'll know this has happened if you hear water hammer. Here's what you should do:

  1. Shut off the water at the main house shutoff.

  2. Open a faucet or two at the highest part of the house.

  3. Find the lowest faucet in the house. This is usually an outside spigot, but it might also be on a laundry tub in the basement.

  4. Open this lowest faucet and drain the system for a while. It doesn't need to be drained entirely.

  5. Turn the water back on and shut the faucets. You're done. The air chambers have air in them again.

Copyright Doug Boulter, 2005

Air Conditioning Fuses

(September 2003)

Even if your house electrical system has been converted to circuit breakers, you still have fuses for the outside compressor of your air conditioning system. Stand outside near the compressor and you'll see a box (usually gray and smaller than 6" x 12") on the wall of the house with a large wire going to the compressor. That's where the fuses are. If you opened the cover of that box, you'd see a pull handle. If you pulled on the handle, a "fuse block" would pull out of the box. The back side of that fuse block would reveal two bullet fuses in holders. Each fuse is about the size of a lipstick tube.

While these fuses almost never blow, when they do, it's often the result of a severe lightening storm in which lightening struck close by. When one or both fuses has blown, there is no physical change in their appearance, so the way you tell is to use a multimeter to check for continuity through the fuse. Most people don't have the equipment to do that, but they will recognize the symptom - the furnace fan works, but the outside compressor won't turn on and there's no cold air.

Save yourself a $100 service call when this happens. Now, while things are working fine, turn off the breaker to your air conditioner. Go outside, open the box, and pull out the fuse block. Pull one of the fuses from the block and go to your favorite home center. Purchase two fuses of the same type and keep them around where you can find them. Then, if your air conditioner compressor won't work, especially after a lightening strike, try changing both fuses before you call a repair person.

And be good to your compressor. Have a service person check the level of the freon charge every other year at a minimum! Do it every year if you have an old system.

Copyright Doug Boulter, 2003

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