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 –Drop the pressure by 5 psi at a time and wait to see
you can do something about it before furtherif you have any complaints.  Showerheads and
damage is done and additional money is wasted.aerators already restrict flow to 2.5 gpm or less. 
Circulating hot water is the fastest way to wear outNewer fixtures like the Evolve line of low flow
your pipes.  In fact 90% of all pinhole leaks and slabshowerheads have pressure compensating
leaks happen in hot water lines for the followingtechnology built into them and work just as well at
reasons:low pressure as they do at high pressure.
- Chemicals in water are corrosiveSecond, turn off the pump when no one is using hot
- Chemicals in water when heated are even morewater.  That’s right.  I said turn off the pump. 
corrosiveAs I mentioned earlier people only use hot water
- Chemicals in water when heated and circulated15% to 20% of the time.  The pump only needs to
through copper pipes that bend around corners andbe on when people need water.
turn up walls and curve around electrical conduit andThere are 3 methods of implementing this strategy:
sewer pipes and are reduced in size as water passes1. The Manual Method
through a building is extremely corrosive2. The Guessing Method
In order to understand the solution it is helpful to3. The Automated Method
know what causes the problem.  With a little insightManual Method
into how domestic hot water recirculation lines orHave someone go to the switch and turn on the
recirc loops are built and how they work we can seepump when you need hot water and turn it off
that the answer is as easy as flipping a switch.when you are done.  Might be practical for a single
Apartments, hotels and larger homes have recircfamily home (certainly not convenient) but impossible
loops designed to move hot water to the farthestin an apartment or hotel.
fixture from the boiler or water heater in aThe Guessing Method
reasonable amount of time.  Each loop has a pumpPlug your pump into a timer and guess when hot
pushing water through a copper pipe 24 hours a day,water will be needed.  This may be a practical
7 days a week.  Each loop has multiple joints andsolution if the number of people living in the house or
fittings that obstruct the flow of water.   Gate orapartment or with a limited number of guests in a
ball valves and flapper checks and expansion tankshotel and everyone has the same predictable need
and whatever else the plumber had on his truck thefor hot water.  Unfortunately when hot water is
day he built the line create disturbances in the flowneeded during an off period the timer gets disabled
path.and never turned back on.
Water likes to flow in a nice straight line with noThe Automated Method
obstructions.  This is called laminar flow – niceThink about your recirculation line as a closed loop. 
and smooth.  Anything in the flow path can disruptWhen there is no demand for hot water, no water
the flow and cause an eddy to form.  Eddies are theenters or leaves the system.  When a hot water
bad boys, the unwanted visitor, the black sheep offaucet is turned on there is a “leak” in the
the family.  system. 
Create a little friction, add in some turbulence and theWhen water leaves the system more water is added
next thing you know you have a leak.from the city water line through a cold water
As your reading this please keep in mind there aremake-up line (this is the technical name for the
things you can do to reduce or even eliminate leaks. copper pipe that brings cold water to your water
They are relatively inexpensive and I’ll tell youheater).
what they are in a minute.If a flow sensor is placed in the cold water make-up
When water pipes leak many things can happenline, any indication of water movement would mean
– none of which are any good.  Pinhole and slabsomeone is using hot water.
leaks, mold, wasted water, wasted energy, propertyIf the sensor sensed a demand (i.e., someone turned
damage, resident/guest complaints and inconvenienceon a hot water faucet) it could turn on the pump. 
all mean one thing.The demand would be met and the pump could be
It cost you time and money.turned off automatically when the demand ended.
The only question left is how much?   Please referThat is precisely how an On-Demand Intelligent Pump
to Table 1 for an idea of how much a leak can cost.Controller works.  The pump is only on when there
Table 1:  The Cost of a Leakis a demand.
$200          You caught the leak early and itAs it turns out, there are many benefits to
wasn't buried in a wall or under a slabautomating your recirc pumps operation:
$1,000       The leak was in a wall and you- Drastically reduces pinhole leaks and slab leaks –
caught it early and it was relatively accessible afterif the hot water is not moving, it is much less
tearing out some drywallcorrosive
$2,000        Same as above except you didn't- Energy is conserved – since people only use hot
catch it early and mold and light structural damagewater 15% to 20% of the time, the pump will be off
had occurred80% to 85% of the time.  That means the
$10,000       The leak was underneath arecirculation line isn’t full of hot water and no
concrete slab but you were able to pinpoint theenergy is being lost.  California Energy Commission
exact locationstudies indicate 37% less energy is consumed when
$20,000       Same as above except you had toan On-Demand Controller is installed.
chase the leak into another roomsNote:  A sufficiently high speed pump is required
$100,000 +  The leak went unnoticed until someone(2,200 rpm or faster) to implement this strategy.  If
got sick and you got suedyou have a high speed pump you will only need an
So there is the doom and gloom.  What’s theOn-Demand Controller.  If not you will need a full
solution?system including a high speed pump.
Good question.  The answer is there are a numberIn conclusion, cut your risks, lower your losses,
of things you can do.  As you go through my listreduce your energy bill and extend the life of you
keep in mind that people only use hot water 15% topipes and water heater or boiler by turning off you
20% of the time (based on a study by the Californiarecirc pump with an On-Demand Intelligent Pump
Energy Commission).Controller.
First, check your water pressure.  40 psi is highContact me directly at the email address below to
enough for most 1 or 2 story buildings.  Be sure tofind out if this solution will work for you or what
check it in several places to find the lowest pressureother options you might have.  To purchase the
in the building. Typically that would be the pointOn-Demand Intelligent Pump Controller click on the
furthest from the water meter.  If you don’tlink below. 
have a pressure regulator, put one in. Do it now and sleep better tonight knowing that one
When implementing this strategy do it in stages. of your biggest headaches just got cured.