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How to Prevent Pinhole Leaks, Slab Leaks and Mold and Conserve Energy by Controlling Your Hot Water Recirculation Pump

If you have had 1 leak, more will surely follow – you can do something about it before further damage is done and additional money is wasted.

Circulating hot water is the fastest way to wear out your pipes.  In fact 90% of all pinhole leaks and slab leaks happen in hot water lines for the following reasons:

• Chemicals in water are corrosive
• Chemicals in water when heated are even more corrosive
• Chemicals in water when heated and circulated through copper pipes that bend around corners and turn up walls and curve around electrical conduit and sewer pipes and are reduced in size as water passes through a building is extremely corrosive

In order to understand the solution it is helpful to know what causes the problem.  With a little insight into how domestic hot water recirculation lines or recirc loops are built and how they work we can see that the answer is as easy as flipping a switch.

Apartments, hotels and larger homes have recirc loops designed to move hot water to the farthest fixture from the boiler or water heater in a reasonable amount of time.  Each loop has a pump pushing water through a copper pipe 24 hours a day, 7 days a week.  Each loop has multiple joints and fittings that obstruct the flow of water.   Gate or ball valves and flapper checks and expansion tanks and whatever else the plumber had on his truck the day he built the line create disturbances in the flow path.

Water likes to flow in a nice straight line with no obstructions.  This is called laminar flow – nice and smooth.  Anything in the flow path can disrupt the flow and cause an eddy to form.  Eddies are the bad boys, the unwanted visitor, the black sheep of the family.  

Create a little friction, add in some turbulence and the next thing you know you have a leak.

As your reading this please keep in mind there are things you can do to reduce or even eliminate leaks.  They are relatively inexpensive and I’ll tell you what they are in a minute.

When water pipes leak many things can happen – none of which are any good.  Pinhole and slab leaks, mold, wasted water, wasted energy, property damage, resident/guest complaints and inconvenience all mean one thing.

It cost you time and money.

The only question left is how much?   Please refer to Table 1 for an idea of how much a leak can cost.

Table 1:  The Cost of a Leak

$200          You caught the leak early and it wasn't buried in a wall or under a slab

$1,000       The leak was in a wall and you caught it early and it was relatively accessible after tearing out some drywall

$2,000        Same as above except you didn't catch it early and mold and light structural damage had occurred

$10,000       The leak was underneath a concrete slab but you were able to pinpoint the exact location

$20,000       Same as above except you had to chase the leak into another rooms

$100,000 +  The leak went unnoticed until someone got sick and you got sued

So there is the doom and gloom.  What’s the solution?

Good question.  The answer is there are a number of things you can do.  As you go through my list keep in mind that people only use hot water 15% to 20% of the time (based on a study by the California Energy Commission).

First, check your water pressure.  40 psi is high enough for most 1 or 2 story buildings.  Be sure to check it in several places to find the lowest pressure in the building. Typically that would be the point furthest from the water meter.  If you don’t have a pressure regulator, put one in. 

When implementing this strategy do it in stages.  Drop the pressure by 5 psi at a time and wait to see if you have any complaints.  Showerheads and aerators already restrict flow to 2.5 gpm or less.  Newer fixtures like the Evolve line of low flow showerheads have pressure compensating technology built into them and work just as well at low pressure as they do at high pressure.

Second, turn off the pump when no one is using hot water.  That’s right.  I said turn off the pump.  As I mentioned earlier people only use hot water 15% to 20% of the time.  The pump only needs to be on when people need water.

There are 3 methods of implementing this strategy:

1. The Manual Method
2. The Guessing Method
3. The Automated Method

Manual Method

Have someone go to the switch and turn on the pump when you need hot water and turn it off when you are done.  Might be practical for a single family home (certainly not convenient) but impossible in an apartment or hotel.

The Guessing Method

Plug your pump into a timer and guess when hot water will be needed.  This may be a practical solution if the number of people living in the house or apartment or with a limited number of guests in a hotel and everyone has the same predictable need for hot water.  Unfortunately when hot water is needed during an off period the timer gets disabled and never turned back on.

The Automated Method

Think about your recirculation line as a closed loop.  When there is no demand for hot water, no water enters or leaves the system.  When a hot water faucet is turned on there is a “leak” in the system. 

When water leaves the system more water is added from the city water line through a cold water make-up line (this is the technical name for the copper pipe that brings cold water to your water heater).

If a flow sensor is placed in the cold water make-up line, any indication of water movement would mean someone is using hot water.

If the sensor sensed a demand (i.e., someone turned on a hot water faucet) it could turn on the pump.  The demand would be met and the pump could be turned off automatically when the demand ended.

That is precisely how an On-Demand Intelligent Pump Controller works.  The pump is only on when there is a demand.

As it turns out, there are many benefits to automating your recirc pumps operation:

• Drastically reduces pinhole leaks and slab leaks – if the hot water is not moving, it is much less corrosive
• Energy is conserved – since people only use hot water 15% to 20% of the time, the pump will be off 80% to 85% of the time.  That means the recirculation line isn’t full of hot water and no energy is being lost.  California Energy Commission studies indicate 37% less energy is consumed when an On-Demand Controller is installed.

Note:  A sufficiently high speed pump is required (2,200 rpm or faster) to implement this strategy.  If you have a high speed pump you will only need an On-Demand Controller.  If not you will need a full system including a high speed pump.

In conclusion, cut your risks, lower your losses, reduce your energy bill and extend the life of you pipes and water heater or boiler by turning off you recirc pump with an On-Demand Intelligent Pump Controller.

Contact me directly at the email address below to find out if this solution will work for you or what other options you might have.  To purchase the On-Demand Intelligent Pump Controller click on the link below. 

Do it now and sleep better tonight knowing that one of your biggest headaches just got cured.

About the Author

On-Demand Intelligent Pump

Mark Franklin is CEO of Saves You Energy, LLC a manufacturer and retailer of water and energy conservation products. As a civil engineer Mr. Franklin was involved in the design of multi-family and commercial projects worth in excess of $100 million.

Mr. Franklin has worked with companies ranging from the US Navy to Embassy Suites and Biltmore Hotels to Stanford Student Housing. Pinnacle Properties, United Development Group and ConAm are among the apartment ownership and management companies that have used his products. School Districts like the Blue Valley School District in Kansas and ESCOs such as Johnson Controls have utilized his technologies to reduce energy consumption.

Mr. Franklin can be reached at mark@SavesYouEnergy.com

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