Sometimes, there is nothing more aggravating than low water pressure. In some instances, it can even be dangerous. Low water pressure problems are so commonplace that the national plumbing codes mandated, several years back, the use of pressure balanced shower valves to minimize injury caused by low water pressure problems.

There is a misconception by many homeowners that low water pressure is something they have to live with. Nothing could be further from the truth! Many low water pressure problems are a result of installation inadequacies. The plumber(s) simply put piping in that was either too small (undersized) or reduced the size of the piping, within a structure, too quickly.

Low water pressure problems can also be attributed to scale deposits inside of piping which reduce their diameter, low pump pressure (houses with wells), leaks in underground lines serving a house, and problems with outdated water mains in municipal systems (rare). These problems can usually be identified very quickly. Municipal water works companies have trained personnel that will visit your house and answer questions regarding your water service. Often it takes very little detective work to determine if one, or several, of these possibilities is the source of your low water pressure. Almost always they will help you determine if there is an underground leak, at no charge to you.

They can also attach a pressure reading device which will tell you just what the water pressure is inside your house when all fixtures are turned off.

You can also stop by your local firehouse. Fire engines are equipped with accurate pressure gauges. When a fire engine attaches to a fire hydrant, before they start pumping water from the hydrant they know what the water pressure is in that water main.

By the way, in case you didn't realize it, the fire hydrants on your street are hooked to the same water main you drink from. The only deviation from this is in some large cities. There are individual water mains specifically for fire fighting, but these are almost always located in dense urban/business environments.

The fire departments often have very specific records and they can tell you the specific pressure of the fire hydrant closest to your house. Stop by and chat with them, you may be surprised at what they can tell you about the water mains in your area!

Robert Boyle

Robert Boyle was an English chemist born in 1627. He was a pretty smart guy. Well educated and very methodical, he started experimenting with gases. He developed Boyle's Law which has to do with the relationship between a given volume of gas and its pressure.

He determined that liquids acted somewhat differently. It didn't take too long for him to determine that water couldn't be easily compressed. In fact, it was virtually impossible.

What he found out was that when you applied pressure to water (liquids) in a closed system (no leaks), whatever pressure you applied, the same pressure was exerted everywhere by the liquid against the container it was in.

This is a very significant finding. It tells you that when all of your faucets are closed in your house, the pressure within your plumbing system should be equal everywhere. Not only that, if you happened to visit your local fire department and/or call the water works, you will know what that pressure should be. The only deviation will be the resultant pressure drop due to friction loss as the water travels from the street into your house.

Those people who operate using well water and electric pressure pumps operate under the same "laws". The only difference is pump capacity. Smaller pumps simply cannot meet the demand (flow) you might impose upon them. They may be able to produce an adequate pressure (50 - 70 pounds per square inch PSI), but when asked to deliver lots of water at this pressure, they choke. You may have to jump to a bigger pump.

This is rarely the problem with a municipal system. The typical water main in a residential street can deliver hundreds of gallons per minute and maintain pressure. To put this in perspective with respect to your own water usage, you might use seven gallons per minute if you had four people using two separate bathrooms at the same time. This situation is somewhat realistic as people get up to go to work and school.

Friction Loss

OK, so we know that the pressure in a closed system is constant because of Bob Boyle's findings. What then accounts for water pressure / volume losses?

Well, a number of things can contribute to water pressure loss. Some of the major items are relative elevation differences between your house (fixtures) and the water main, size of water piping and restrictions in a pipe. The two most likely culprits in most cases are the last two, water pipe size and restrictions. These two items have a huge impact on friction loss. Friction loss can dramatically affect water pressure. What happens is simple. When water starts to flow through a pipe, some of it rubs against the side of the pipe. Depending upon how much water is rubbing against the inside walls of the pipe in relation to how much water is in the pipe in any given length, determines how great the pressure loss will be.

The technical term for this situation is called the hydraulic radius. But who cares about that, let me show you a simple example.

Bigger is Better

Let's look at a cross section of a 1/2 inch inner diameter copper pipe. Remember that grade school math homework you didn't do??? Well, it's payback time!

The inner circumference of the 1/2 inch pipe is 1.57 inches. The area of the cross section of this same pipe is 0.19 inches.

Let's look at a 3/4 inch pipe. It's inner circumference is 2.35 inches. It's cross sectional area is 0.44 inches.

Now, these numbers may seem either confusing or insignificant. But, look a little closer. Notice that when we jumped to 3/4 inch pipe, a funny thing happened. The circumference increased by 49.6 percent. But, the cross sectional area increased by 131.5 percent!

This means that as a pipe gets bigger, there is more room to move around. Not as much of the fluid in the pipe has the opportunity to rub against the sides of the pipe.

Restrictions inside pipes can also cause friction loss. Imagine a rough scalely pipe. The water trying to get from one end to the other hits and rubs against lots of "things". It loses energy. What's more, the deposits inside the pipe reduce its inner diameter. As shown above, small inner diameter pipe causes great pressure loss because of friction loss.

So, with respect to pipe size and pressure, bigger is better!

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Soldering Copper Water Lines

Copper doesn't rust. As such, it has become one of the preferred materials to use in residential water distribution systems. Copper, however, can corrode in certain circumstances.

Copper pipe and copper fittings are attached to one another by using solder. Solder is simply a metal, or combination of metals, that when heated bond to the copper. Think of the solder as a very permanent glue. Some metals which are used in solder are tin, antimony, silver and lead. Lead solder was used years ago because it flows at lower temperatures and is a "thicker" solder. Think of it as a maple syrup type solder. It has the capability to fill larger gaps between a pipe and a fitting in case the fit is sloppy. However, lead is poisonous! Don't use a solder that contains lead for water supply lines. It can be used safely for copper drainage lines. Look for solder that is often sold as "95-5". This is a solder that contains a mixture of tin and antimony. It is safe for water supply lines. Silver solder is often used for copper gas lines. It melts at a much higher temperature. The key to soldering is to get the surfaces which will be soldered clean. That's easy. You can use steel wool, sandpaper, plumber's cloth (a fancy sandpaper) and special wire brushes (for the inside of fittings) to accomplish this task. After they are clean, don't touch the cleaned areas! Dirt, grease, etc. from your fingers will spoil the solder job.

Now apply flux evenly to the two pieces which are to be joined together. Flux is a chemical compound, frequently zinc chloride. It removes oxidation which allows solder to bond more easily to the copper. It is often sold as a paste that has the consistency of petroleum jelly. Always stir flux with a clean stick to thoroughly mix. If allowed to get warm or hot, the zinc chloride will separate from the paste.

Apply heat to the assembled fittings and pipe. Heat with a propane or acetylene torch, being careful not to set adjacent combustible material on fire. Heat until the flux stops bubbling. Pull the torch away and touch the heated joint with the solder. It should begin to melt within two seconds. If not, heat again with the torch. If you heat the copper just right, the stored heat in the pipe and fitting will be more than enough to melt the solder. Applying heat with the torch WHILE soldering can give misleading results. The solder may melt at the edge of the joint, but not flow into the joint. Many an apprentice plumber and DIYer has found this out the hard way!

Repairs to existing copper lines are tougher. Existing lines need to be drained of all water. You simply can't solder pipes that contain water. The water absorbs too much heat and doesn't allow the pipe to get hot enough to melt the solder.

If you have to repair existing lines there is an easy way to drain the water lines. Turn the water off at your main shut off. Next, flush all toilets and open all valves everywhere as quickly as possible, starting at the top of your house. Go to the lowest faucet and open it and the water will flow to this low point suctioning much water from the lines.

If you have a persistent drip at the repair sight, use this trick as a last resort. Do all your prep work to the joints. Have everything ready to go, torch, solder, etc. Get a piece of white bread. Remove the crust. Make a ball of bread, firmly packed, slightly larger than the inner diameter of the pipe that is dripping. Insert the bread into the pipe and push it 4 to 6 inches away from the joint with a small stick. Quickly assemble the pipe, heat and solder. The bread should give you a 30 to 45 second window in which to solder.

Finally, always keep a bucket or two of water handy in the event you start a fire. I have used it on more than one occasion!

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Calculate Water Pressure Loss

Years ago, engineers developed tables to quickly calculate water pressure loss. They're often referred to as hydraulic friction loss tables. Studies produced constants (numbers which you use to help in the calculation) which make the math fairly easy.

What Do You Need to Know to Calculate Pressure Loss?

You need to know several things:

• size of pipe
• flow in gallons per minute (GPM)
• the distance which the water flows

Do Fittings Affect the Actual Distance?

Yes, fittings increase the actual distance. If you have lots of bends and tee's, 100 feet of pipe might really be 130 feet or so.

Flow is the thing that stumps most people. Flow rates can also be found on tables. Here are some standard flow rates for residential fixtures:

• toilet - 2.5 GPM
• kitchen sink - 1.25 GPM (H or C - times 2 if both handles are wide open)
• washing machine - 1.6 GPM (H or C - times 2 if H & C on at the same time)
• shower 2.5 GPM (both hot and cold on at the same time)

What are the Constants?

Now for our constants. I have listed several to show the relationship as the gallons per minute of flow increases.

Listed are 1/2 and 3/4 inch copper pipe Type M. Type M is the standard grade of copper tubing used in residential construction.

What are the Pressure-Loss Constants for Small Pipe?

The constants listed are pressure loss per hundred feet of pipe run.

Notice the difference in the constants for different-sized pipe, but yet the same GPM flow! It's HUGE. See why 3/4 is better?

Now, here is how you do a pressure loss calculation.

By the way, we need one other constant and it is a number that relates to pounds per square inch. It's really pretty complicated, so I would appreciate it if you would just trust me on this one. The number we need to remember is 0.4335. Okay, if you don't trust me and want to know more about the secret constant of 0.4335, click or tap here.

Can You Do A Sample Pressure-Loss Calculation?

Yes, let's calculate what will happen to the pressure if we flush a toilet while a shower is running in a bathroom 100 feet away from where the water enters the house. We are using 1/2 inch pipe.

Toilet flow = 2.5 GPM Shower Flow = 2.5 GPM Total flow = 5 GPM

Constant from table multiplied by 0.4335 = Pressure loss in PSI
39.2 X .4335 = 16.99 PSI

If we substitute 3/4 inch pipe, here is the calculation:
6.94 X .4335 = 3.00 PSI

Quite a difference!

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Cast Iron Pipe Tips and Suggestions

Cast iron pipe is really easy to install. I have installed it myself on several recent jobs. You really only need two tools to install this fine material: a snap cutter and a small torque wrench. The snap cutter is an interesting tool. There are two types of cutters, both of which cut cast iron pipe by snapping it in two. The cutter has carbide cutting wheels that are attached in between the links of a chain. The wheels surround the pipe at the point where you want it cut. You apply pressure to the cutter with your arms and BINGO, the pipe snaps in two very cleanly.

Assembly of the pipe is even easier. The pipe and fittings are attached to one another by using rubber gaskets that slide over the ends of the pipe. The gaskets have small ridges on the inside to firmly grasp and seal the pipe. A large stainless steel band completes the installation. This clamp slides completely over the rubber gasket and squeezes it firmly against the pipe. When the clamps are installed properly and tightened according to the manufacturer's recommendations, the joints absolutely will not leak. Since the clamps are made of stainless steel, moisture, salt spray, etc. will not affect them.

Weight Considerations

Cast iron is a heavy material. It needs to be supported adequately so that it does not fall. Homeowners or non-professional plumbers who try to do their own installations often do not install adequate supports when installing drain piping. This is especially true of plastic PVC piping. They feel how light the pipe is and feel that they only need to support the weight of the pipe.This is where they make a mistake. What they fail to take into consideration is the weight of the pipe when it is filled with water! Drainage pipes can readily fill with water for two reasons: clogs or temporary filling due to large discharge amounts of water from multiple fixtures. I have seen a small 1 1/2 inch branch line from a kitchen sink completely fill with water when a standard double bowl sink was drained. Recently, I relocated my kitchen sink drain line. After the work was completed, I filled the sink bowls to flush the line of any small installation debris that may have found their way into the plumbing lines. Because I installed a cleanout which faced the ceiling, I was able to view the water as it rushed by. I was amazed to see the entire pipe fill with water as the plugs were pulled from both sinks.

You may choose to use this information to help you keep your drain lines clear. I do this once a week. I fill both sinks with water and pull the plugs! Flush a toilet or two at the same time if you wish to really clear your entire sewer line. If the plumbing system is sized correctly and you have no obstructions, you will not cause any harm to your system.

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Water Supply Line Installation Tips

High Anxiety

Many a homeowner backs away from soldering copper pipe. The torch, molten solder, leaks, high pressure, etc. cause one to hesitate. Heck, isn't that one reason why plumbers make so much money? Well, I'm a plumber and I'm here to tell you that with a little knowledge and one or two practice joints, you can successfully solder leak-free joints in copper tubing.Yes, the process is dangerous, you can cause fires, you can burn yourself (I have various deep scars from serious third degree burns), however, I can't recall reading a story in the paper about a homeowner who drowned from repairing a copper line. If you do fail, so what? Call the plumber to bail you out (figuratively speaking of course!)

The Basics

To solder copper pipe you must heat the copper pipe and the fitting to be soldered to a sufficient temperature. When the copper is hot enough, it will actually draw the solder into the joint by capillary attraction. Believe it or not, solder will actually flow uphill. A simple propane torch that uses screw-on bottles will adequately solder pipe up to 3/4 inch in diameter. Plumbers generally use acetylene torches for two reasons. The acetylene burns hotter than propane, allowing for faster solder times. The acetylene is available in larger tanks which attach to handy hoses and lightweight torches. If you want acetylene, you just need to go to a large plumbing supply house or a place that services welders.

Solder, which is available in leaded and no-lead versions, attaches to the pipe on a molecular level. The surface of the soldered joint actually becomes an alloy where the copper and solder intermix. For this to happen, the copper must be very clean and free of oxidation. You can clean copper pipe in any number of ways. You can use coarse steel wool, sandpaper and/or a wire brush. Special round wire brushes come in a variety of sizes to clean the inside of copper fittings and valves. Simply twist the brushes or pipe to clean them. Even if you purchase new copper pipe, it too should be cleaned. You only need to brighten the area which is to receive solder.

Flux - The Catalyst

Flux is a chemical which helps you solder. It actually finishes up the cleaning job you started with the sandpaper and brushes. In addition, it prevents the pipe from oxidizing as you heat it. You can solder without flux, but it is really difficult! Flux is applied to both the pipe and the fitting with a handy miniature paint brush. You do not need massive amounts to be effective. Besides, once you start to heat the pipe, 90 percent of it boils off and evaporates.

Solder - Different Types - Beware!

Solder is available in three types: 50 percent lead/50 percent tin; 95 percent tin-antimony/5 percent lead; and lead-free solder.

Any water supply pipe should be soldered with solder that contains no more than five percent lead. If possible, use the lead-free solder. The 50 percent lead solder is used for copper drain lines. It melts at a lower temperature and is able to bridge larger gaps as it cools. This is handy when working with large diameter (up to 4 inch!) copper pipe and fittings.You MUST pay attention when you buy solder. The 1 pound rolls look very much alike. Carefully look at the label as you might purchase the wrong one.

Lighting & Working with a Torch

Plumbing torches can be lit with matches, lighters or preferably a flint striker. Matches and lighters can be dangerous, as you might not put them out. A flint striker makes sparks which ignite the flame. Plus, a single flint in a striker can last a homeowner 10 years or more!

Flame temperature is important. You need to set the flame on medium or high to generate enough heat to melt solder. If your flame is adjusted correctly, it will burn different shades of blue. You will notice at the center of the flame a darker blue section that comes to a point. This is the hottest part of the flame. You apply this part of the flame to the copper pipe.

Don't be afraid to heat both sides of the pipe. Rotate the torch around the joint for even heat distribution. When I use my acetylene torch and I am soldering 1/2 inch pipe, I can usually heat the pipe to the correct temperature in 10 seconds or less. A propane torch may take 15 to 20 seconds.

Always look beyond the pipe. Extremely hot temperatures are beyond the visible portions of the flame. You can easily scorch lumber or wires. If you are soldering near old lumber or in joist spaces near vertical walls, you can easily start your house on fire. Be careful and use flame shields. These are flame resistant fabrics or simple pieces of sheet metal which absorb and/or deflect the heat.

Applying Solder

As you heat the pipe and fitting you will see the flux begin to boil and evaporate. Once the flux stops boiling the pipe is generally hot enough to solder. Move the torch away and touch the solder to the pipe. It may take 2 to 3 seconds for the solder to melt. If the pipe is horizontal, apply the solder to the top of the pipe. The solder will roll around in an instant. If you have done the job right, a droplet of solder will be at the bottom of the joint. You can flick this molten solder away with an old rag. Blowing on the joint will allow it to cool. It will be hot, but rub the joint quickly with an old rag to remove flux residue. This will also polish the solder. Check the joint closely to see if you see a silver-colored band around the entire joint. If so, your first solder joint may be perfect. As I would say on a job: Another quality installation!

Common Causes of Soldering Leaks

Virtually every soldering leak is a result of "operator error" - that is, it can be traced to some fault on your part. Here is a list of some of the most common causes for failure. Most are easy to correct. Some will give you problems.

Insufficient Soldering Temperature

This is the most common problem. Rookies and homeowners apply the torch to the joint to be soldered. They follow immediately with the solder. Within 2 to 3 seconds the solder melts from the intense torch heat. However, the copper pipe and fitting have yet to reach the necessary temperature to allow the solder to be drawn deeply into the joint.

Insufficient or Stingy Use of Solder

Often leaks result because just one side of the joint was soldered or the solder was not left on the joint long enough. Try to look at all sides of the joint after soldering. If you do not see a thin silver line where the fitting meets the pipe, you may have a problem!

Flux Failure

The solder paste or flux that helps the solder flow in the joint can cause problems. First, if you have not thoroughly stirred it before use, you can have a problem. The chemicals in the flux can separate, especially in hot weather. Also, you can get the flux too hot and burn the joint.

Dirty Pipes - Hand Grease

You must already get the message that both the pipe and the fitting surfaces that are to accept solder must be perfectly clean. I have had problems where I touched a pipe surface with my hands before fluxing. The oil and grease from my hands fouled the pipe!

Water in the Lines

You can't solder copper pipe with water in the lines (unless you have a super powerful torch with a special tip.) The water acts as a heat sink. You can't get the pipe hot enough to melt the solder. A common problem is water that drains from above as you try to solder. Homeowners often can't trace the source. Well, you must open all valves to all fixtures and even flush the toilets! The best way I have found to evacuate the lines is to turn the main water valve off. Go to the top of the house and open all the faucets. Proceed to the basement opening valves on the way. Then open the lowest valve in the system. Had your plumber installed a boiler drain valve right next to the main water valve you could really do the job right! Just attach a hose to this and empty the water at a floor drain. This method allows you to get just about every bit of water from the lines.

Pressurizing the System too Early

If you have just one simple joint to solder, you can ruin it by turning on the water too quickly. You can actually blow air and water right through the hot, molten solder. I did this 20 years ago, I know!

It sometimes can take up to 20 or 30 seconds for a pipe to cool sufficiently. You can always cool it by pouring or spraying water on the pipe. Watch out for steam!

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Color Photos of Plumbing Vents

Here is a tub drain pipe and partial vent system. This is what the average bathtub drain and vent system looks like if you could remove the drywall or plaster from your walls. The plastic pipe connected to the tub is the overflow pipe. The chrome fitting up high on the inside of your tub is the overflow. Water enters it and flows down into the pipe. Just before the white pipe enters the gravel, you can see a tee fitting. Attached to it is a pipe that connects to the bottom of the tub drain outlet. The vertical pipe connected to the tub drops into a standard P-trap similar to one under any sink in your home. This trap connects to another tee fitting that is beneath the floor and is attached to the vent pipe that is passing through the notched wood floor plate.

I have drawn an isometric drawing above to illustrate the actual piping connections in this situation. It should make sense to you.

Another Vent Pipe Photograph

This photo is a continuation of the tub drain from the previous photo. In the isometric diagram above, I showed you - using the dashed line - the vent pipe that extends up straight to the roof. In reality, they rarely do this. Vent pipes can have all sorts of twists and bends in them as they travel from a fixture up to the roof. In fact, they can connect with other fixture vent pipes. This is why you might only see one or two vent pipes on a roof when the house below might have 10 or 15 separate plumbing fixtures.

In this photo, you can see how the vent pipe from the tub travels vertically up about four feet off the floor. It then travels horizontally until it intersects the vent pipe that services the toilet. You can clearly see the toilet flange on the concrete floor inside the bath area. The vents then travel horizontally a short distance and then start to go up once more towards the roof. They have a long way to go as this is a two story house and this bathroom is in the basement.

Whenever a vent pipe travels horizontally it needs to have fall so that condensate or rain water drains down the vent towards the fixture. You never want water to lay in the vent pipe as this water could block air that is trying to get to the fixture each time bath or sink water flows down the drain pipe.

You can also see that the vent pipe is protected from nail or screws with metal protection plates. These are a must as the wood framing is very thin after the holes have been drilled to accept the piping. It is a superb idea to take photos of the walls after all pipes, wires, etc. have been installed. Imagine how helpful photos such as these would be if you were remodeling or getting ready to drive a random nail in a wall. You would know what is behind the drywall!

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I don't believe the average person realizes the dynamics of the plumbing drainage system in their home. After all, the water flows out of the sink and disappears. As long as this happens each time, who really cares what is going on?

But I have come to believe that knowledge is power. The more you know the better you are equipped to handle problems. This holds true with many things in residential construction, including plumbing drain and vent systems.

Sanitation is the Goal

If you study the history of plumbing, or visit a third world country, you quickly begin to appreciate the advancements of modern plumbing. Turn the clocks or calendars back just 125 years ago and you discover that plumbers were treated with as much respect and reverence as doctors. The medical profession connected the dots after the Civil War and learned that the spread of many common diseases was linked to poor sanitation.

Doctors discovered that bacteria in plumbing systems could easily spread in a household if waste and contaminated water was not disposed of properly. A simple open pipe in a sink proved to be inferior. It allowed vermin as well as noxious fumes to enter the house through the pipe. It didn't take long for the simple plumbing trap to be invented. The water seal in the trap stopped small vermin and blocked fumes from entering the living space.

Before long, plumbers learned what happens when water flows down a pipe. They discovered that the water that flows into a pipe displaces and removes air from the pipe. They learned that flowing water can actually create a powerful vacuum. Vacuums are a bad thing in plumbing systems as they can remove water from traps. Shortly thereafter, plumbers determined that pipes must be connected to the system that allows air from the atmosphere to enter the piping system. This air stopped vacuums and helped to improve sanitation within a home.

Venting Tips

Plumbing vent pipes are not much different than the drainage pipes. They typically are smaller than the drainage pipes for several reasons. First, they are designed to transport air. Air can be compressed and the quantity of air traveling in a vent pipe can be increased by simply boosting its velocity. Since water drains through a vent system by gravity, you generally can't increase its velocity. But a powerful vacuum within a drainage system that is created by a large volume of water can increase the velocity of the air entering the vent pipes.

It is not uncommon for all of the drainage pipes in your house to eventually join together and leave the house through a single pipe. Venting systems can be designed to do the same thing in reverse. I have plumbed many a house that had over ten fixtures that were served by a single 3 inch vent pipe that poked through the roof.

Awesome Books

If you want to learn more about plumbing vent systems, you should get a few books on the subject. One of my favorites is a book titled Plumbing a House written by Peter Hemp. Peter has included some wonderful 3D diagrams and superb diagrams of all sorts of drain and vent combinations. This book is worth three times the purchase price.

Keep in mind that you must always follow the plumbing code. It is in place to protect you and your family. Be sure to read up on the subject and practice working with pipe materials before you started plumbing in earnest.

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Steaming hot water as soon as you turn on a shower valve is a great feeling on a cold morning. The same is true at your kitchen sink or any other plumbing fixture. As our lives become more fast paced, we don't want to wait for anything. Instant gratification is unfortunately becoming the norm.

The installation of a hot water recirculating loop system will allow you to have hot water at your fixtures. Those people who have their heaters below the piping system get the recirculating work done for free Those who live in slab houses or who have hot water lines below the heater must use inexpensive in-line recirculating pumps. The point is that you do not have to wait for hot water.

New Construction vs. Existing

If you are building a new home or rehabilitating one, now is the time to put in a recirculating loop! You will have no trouble installing the return loop lines and insulating all of the necessary pipes.

If your house is an existing two story house, it can be tough to get a return loop pipe up close to the second floor or higher bathrooms.

It is also virtually impossible to properly insulate all of the hot water supply pipes.

Existing ranch style houses that have a great majority of the plumbing pipes exposed in the basement are the best candidates for retrofitting. These houses allow you to insulate all but just a few feet of hot water supply lines. They also permit you to install a return loop close to each hot water fixture.

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Retro-fit Recirculating Pump Manufacturers and Tips
Sean Dougherty, an individual who works for The MWW Group, a public relations firm, was kind enough to develop this cool comparison of retrofit hot water recirculating pumps:

www.metlund.com Metlund's product, the D'MAND, requires the pump and valve to operate together under the sink, which creates a secondary requirement for electricity under the sink where there is not usually an outlet. In addition, it requires the user to activate it to call for water - in residential applications this will typically be a pushbutton. Therefore, the system saves the water and energy but doesn't provide instant hot water. At Grundfos, we don't spend a lot of time talking about cost savings with this product because we recognize that with water costs strictly regulated, the dollars returned from the water savings are modest. We do stress the comfort (hence the name) because that is the main sales feature of this type of product

www.lainginc.com/instant.htm Laing's Autocirc product uses a similar concept to the Grundfos Comfort Instant Hot Water System but without the timer - creating a recirculation loop using existing hot and cold water pipes. Instead of using the thermally activated valve, Laing's pump turns on automatically whenever the hot water supply line water cools and replaces that water with hot water. Of course, this 24-hour operation means more electricity use and more heat constantly in the pipes. Absent excellent insulation, this will drive up cost of operation. In addition, the pump is positioned under the sink, not in the boiler room, increasing the odds that electrical work will be necessary in addition to the plumbing.

www.grundfos.com Here is the one. It is Tim Carter, me talking now. The water circulation system that eliminates cold water runoff at the faucet, using a bypass valve and pump with a timer to control water flow. (You can find the nearest distributor at the Grundfos USA web site.) No return line is needed. The bypass valve has a thermostat that senses when hot water has reached the farthest plumbing fixture. The timer on the pump allows you to control when hot water is at the fixtures you need it to be at and when! This is the real deal. I highly urge you to give the Grundfos Comfort Series Pump a serious look.

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Hi Tim,

Do I leave the valves open or closed when you solder them in the line?

David Griebel

- - -

Hi Dave,

It depends upon the type of valve! If you are soldering a traditional valve that has a rubber or plastic washer, then you open it. It you are soldering a ball valve, you keep it closed.

Once the solder is set, you should try to slowly cool the valve body to stop the heat transfer towards the actual washer and ball.

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