Thread: Circ pumps thinning copper pipe

Has anybody come across the thinning of copper piping near fittings resulting in pin holes and leaks caused by constant circulating hot water?

I am aware of a situation where this appears to be the case. This home was built in the early 90’s and has had 2 water leak events in the circulation line.

Plumbers that I have spoken with told me that the constant movement of the hot water breaks down the copper.

Comments and experiences appreciated.

Thanks, Chip


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See "Water Velocity Limitations" on pp 11 here:

http://www.copper.org/publications/p...e_handbook.pdf

Good information, from page 11:
Water Velocity Limitations—
To avoid excessive system noise and
the possibility of erosion-corrosion, the
designer should not exceed flow
velocities of 8 feet per second for cold
water and 5 feet per second in hot water
up to approximately 140°F. In systems
where water temperatures routinely
exceed 140°F, lower flow velocities
such as 2 to 3 feet per second should not
be exceeded. In addition, where 1/2-inch
and smaller tube sizes are used, to guard
against localized high velocity turbulence
due to possibly faulty workmanship
(e.g. burrs at tube ends which were not
properly reamed/deburred) or unusually
numerous, abrupt changes in flow
direction, lower velocities should be
considered. Locally aggressive water
conditions can combine with these
two considerations to cause erosion-
corrosion if system velocities are too high.
Water Velocity Limitations—
To avoid excessive system noise and
the possibility of erosion-corrosion, the
designer should not exceed flow
velocities of 8 feet per second for cold
water and 5 feet per second in hot water
up to approximately 140°F. In systems
where water temperatures routinely
exceed 140°F, lower flow velocities
such as 2 to 3 feet per second should not
be exceeded. In addition, where 1/2-inch
and smaller tube sizes are used, to guard
against localized high velocity turbulence
due to possibly faulty workmanship
(e.g. burrs at tube ends which were not
properly reamed/deburred) or unusually
numerous, abrupt changes in flow
direction, lower velocities should be
considered. Locally aggressive water
conditions can combine with these
two considerations to cause erosion-
corrosion if system velocities are too high.

I remember an old pool contractor doing an inspection on a pool at a home that I was inspecting some years ago. The circulation lines used copper and he felt that they would be largely worn out because of just what you are referring to. However, this was an old pool and pool pumps are a much higher velocity and volume of water.

I believe the condition you described is caused by Cavitation

What is Cavitation?

Cavitation

Originally Posted by Raymond Wand

I believe the condition you described is caused by Cavitation

What is Cavitation?

Cavitation

Which is typically caused by improper reaming, or not reaming, fittings, also excessive solder. Anything inside the pipe which disrupts the smooth flow of the water.

However, water flow speed which is too fast can also cause problems.

When the damaged piping was removed it was noted that the original cut ends had not been properly reamed or de-burred. The plumber that made the repairs commented on this condition and said the plumber that did the original work did not follow plumbing code and could be held responsible for repairs.

All comments and experiences related to this are appreciated.

Thanks, Chip

Air entrainment is a likely possibility as bubbles under pressure act as projectiles in the fluid. If a fitting is located less than a certain number of pipe diameters away from the pump discharge (forgot the exact no.) it changes the laminar flow characteristics of the fluid and will also cause erosion.

Originally Posted by Chip Roberson

When the damaged piping was removed it was noted that the original cut ends had not been properly reamed or de-burred. The plumber that made the repairs commented on this condition and said the plumber that did the original work did not follow plumbing code and could be held responsible for repairs.

All comments and experiences related to this are appreciated.

Thanks, Chip

The trouble of saying the work is "Original" on a home that was built in the 90's can be hard to prove. There can be to many "what ifs" like what if the circ pump went bad 3 or 4 years later and they had a handyman change it for them or they changed it themselves? One thing I do as a plumber on systems that can be easily modified after I leave is I take Polaroid snap shops of the work and the units installed as well as document the model and serial numbers of the devices.

I had a home owner call my office a week after I installed a ISE garbage disposal. They said I installed it wrong and now it is burned out. They told my boss they did not me back, they wanted another plumber. One of our other plumbers went there with the photo's and the documents. and found that they had removed the new disposal and installed some other unit. Turns out they had a bar sink with a defective 10 year old unit so they swapped units. So as a good plumber I documented everything and protected the company from the home owner committing fraud. As inspectors you should always document everything as well just to cover your arse.

Originally Posted by Ron Hasil

The trouble of saying the work is "Original" on a home that was built in the 90's can be hard to prove.

Chip was not stating that the piping was "original to the home", but that the removed pipe and fittings, i.e., "original", were not properly reamed and deburred, where the new, i.e., "replacement" pipe and fittings would be.

Not that "new" does not mean "new forever", just like "original" does not mean "original to the house".

When you remove a damage piece of pipe (could be wire, duct, anything) and replace it with new, the piece removed becomes "the original" piece - regardless of when it was installed "originally".

Originally Posted by Jerry Peck

Chip was not stating that the piping was "original to the home", but that the removed pipe and fittings, i.e., "original", were not properly reamed and deburred, where the new, i.e., "replacement" pipe and fittings would be.

Not that "new" does not mean "new forever", just like "original" does not mean "original to the house".

When you remove a damage piece of pipe (could be wire, duct, anything) and replace it with new, the piece removed becomes "the original" piece - regardless of when it was installed "originally".

There is still the assumption of the not properly reamed pipe was installed by a plumber. When home inspectors or other plumbers make that assumption it can cause headaches for the plumber that may have piped it properly when the home was built if the piping has indeed been changed since then with out any decimation proving so.

In Chicago they require a plumber to get a permit for any aspect of a job be it a repair on the potable water supply, repair on a recirc system for radiant heat, to cleaning a drain. All that is involve in getting these permits is to call City Hall permit office tell the scope of work and mail them a check. Now if this is done on a regaler basis a new home owner just getting into a home could call City Hall and see what kind of work has been done on the home. I am not saying this is a perfect system but it is a way of a plumber to cover their arse from others making changes to the plumbing system.

As I mentioned in my first post there has been two leak events. The first event was approximately within the first 8 years which cost for repairs was $5000+ and the second event was last week which will cost $3000+ to repair. The plumber service call was $80, the remaining cost was for the restoration.

The only piping that has been replaced is where the leakage occurred. There is a good chance that future leaks will occur. In order to replace the entire ½ inch circulation line, finished drywall and ductwork will need to be removed for access.

I attached 2 photos of the defect.

Originally Posted by Chip Roberson

As I mentioned in my first post there has been two leak events. The first event was approximately within the first 8 years which cost for repairs was $5000+ and the second event was last week which will cost $3000+ to repair. The plumber service call was $80, the remaining cost was for the restoration.

The only piping that has been replaced is where the leakage occurred. There is a good chance that future leaks will occur. In order to replace the entire ½ inch circulation line, finished drywall and ductwork will need to be removed for access.

I attached 2 photos of the defect.

Wow, that Tee its was in real bad shape , and you can tell the soldering job was not up to par. I was going to suggest a product like the Water Titan After seeing the picture of the Tee the leak seems to be inside a wall so the Water Titan wouldn't be a huge help but you can put its sensors in areas once they detect a leak it shuts off the water supply to the house.

I do wish there was a clear picture of the piping of the top of the water heaters. Its hard to tell if they have them plumbed in in a parallel or serial installation. As well as how the recirc pump is tied in. Also are you on a well?

Originally Posted by Chip Roberson

When the damaged piping was removed it was noted that the original cut ends had not been properly reamed or de-burred. The plumber that made the repairs commented on this condition and said the plumber that did the original work did not follow plumbing code and could be held responsible for repairs.

Originally Posted by Ron Hasil

There is still the assumption of the not properly reamed pipe was installed by a plumber.

There is nothing wrong with making the assumption that another plumber did the work, especially with a plumber making that assumption.

Should one assume instead otherwise?

Jerry all I am saying is never assume something with out facts to back it up. How would you like if someone calls you out of the blue saying you did not do your job right 10 years ago when you inspected a home, due some home inspector that is now inspecting the house which is going up for sale. How does this inspector today even now that the violation was even present at the time you inspected a home? How does he know that things where not modified since then?

Just because a plumber is saying the other plumber did imperfect work does not mean the plumber that built the home was the last one to ever work on the system. To even say the last person that worked on the system was even a plumber. That is why I never assume anything. Yes I will tell a home owner that there is something wrong with the way something is plumbed in. But I will never make the assumption that a plumber, homeowner, or even a handyman did it. Now if the home owner has invoices showing who did the work last, I will tell them to contact that person and give them a chance to correct it themselves. And if the person that did the work was not a licensed plumber give them a chance to hire one to fix the mistakes made. If that fails then call me back and I be happy to make the repairs, and write up an invoice to what repairs where made as well why, but I will not accuse anyone in my invoice of fault. Mainly due to the fact I have no idea who was the last person to touch the plumbing system.

Here is another attached photo. I hope this give you a better view.

Thanks Chip

A plumber once told me that 90 degree bends that are not 90 degrees can lead to premature leakage due to the water 'burning' a hole through the pipe from the way it swirls. I can't say I've ever seen this happen or am totally on board (the plumber was a bit of a 70's burn out) but it seems relevant.

Originally Posted by Chip Roberson

Here is another attached photo. I hope this give you a better view.

Thanks Chip

Ok from what I can make out the water heaters are installed in parallel configuration. Meaning the cold supplies of each water heater are tied together and the hot outlets of each heater are tied together. One big problem in this type of an installation the distance and number or turns as well as sharpness of turns in the flex connectors used here must be of equal distance and turns to each heater from the tee. The slightest difference on the supply pipe and outlet pipes between the two heaters will cause the water to draw water from one heater more often than the other. Now this doesn't have anything to do with your pipes leaking but can be a problem in one of the heaters burning out more often than the other.

I myself prefer the serial installation of twin heaters. Which is where the cold water supply goes into tank one the hot of tank one goes into the cold inlet of tank two and tank twos hot supplies the home. Now you set tank one to raise the water temp to 90 degrees. Then set tank to to 120 degrees. This way tank one is doing approximately a 40 degree rise (assuming city water is coming in approx 50 degrees) and preheating the water to tank two and tank two only has to do a 40 degree rise to the final desired temperature. The recovery is very quick this way and both heaters get an equal work out. Oh the recirc pump would return the water to tank two.

The Recirc pump you have is not a high velocity pump Looks to me its a LAING pump with a timer on it UCT-303-B As I said before that one pick of the TEE in the wall that defiantly was a poor solder job. you can tell by the solder running down the pipe and all the green can of been caused by a few things, one if the person that soldered that tee didn't clean off excess flux it would corrode like that, other is if it was a poor solder job that has been leaking a very small amount for a long period of time, and last ting I can thing of that would cause that is electrolysis, which is caused by the coper touching indifferent metals like electrical conduit or galvanized fittings mixed into the copper system. Sometimes I seen where people grounded appliances on water pipes which caused the same. I hope this helps a little. Also I am sorry for semi-hijacking the thread about assumptions and such with Jerry.

Originally Posted by Ron Hasil

I myself prefer the serial installation of twin heaters. Which is where the cold water supply goes into tank one the hot of tank one goes into the cold inlet of tank two and tank twos hot supplies the home. Now you set tank one to raise the water temp to 90 degrees. Then set tank to to 120 degrees. This way tank one is doing approximately a 40 degree rise (assuming city water is coming in approx 50 degrees) and preheating the water to tank two and tank two only has to do a 40 degree rise to the final desired temperature. The recovery is very quick this way and both heaters get an equal work out. Oh the recirc pump would return the water to tank two.

Ron,

When installing two water heaters I also prefer to connect them in series, however, many prefer to connect them in parallel (although their reasoning escapes me).

However, when connected in series, I prefer setting each to 120 degrees, burning out one element a little before the other is not that big of a concern, and with the first water heater preheating the water to 120 degrees, the total amount of how water available is greater, and recovery is faster, then if it were set to only preheat to 90 degrees.

Not sure that it really makes that much difference on the life of the elements, or on the amount of hot water available (how many people are going to use 80 gallons of hot water anyway?

Chip,

What is on the other side of that wall? The wall is not sealed around the drain pipe. Also, there is a section of NM cable hanging over the edge of the wall at the top - is it being pinched?

Looks like the plug for the recirculating pump is only partially plugged into the receptacle, that could lead to poor connections of the plug blades and the plug or receptacle burning out. The fitting where the cord goes into the pump also looks like the wrong type of fitting, it should be a clamping strain relief, that looks like an adapter for flexible conduit.

Originally Posted by Jerry Peck

Ron,



Not sure that it really makes that much difference on the life of the elements, or on the amount of hot water available (how many people are going to use 80 gallons of hot water anyway?

Jerry,

have you seen the new gas water heater that Bradford White came out with? Model is GX series. The Gx2-25S which is a 25 gallon water heater,can provide 155 gallons of hot water within the first hour. Compared to a standard 50 gallon gas fired water heater which only delivers 90 gallons with in the first hour. This is a lot more cost effective for people that seem to run out of hot water with their 50 gallon tank and was considering adding a second tank or converting to properly sized Tankless. If not here is the spec sheet on it. http://www.bradfordwhite.com/images/...eets/115-B.pdf The way this heater does this is they raised the BTU's to 78,000 and they have the thermostat set to 180 degrees. On the top of the heater is a temperature tempering valve that will bring the output water temp back to 120 degrees.

Ron; that is one sweet water heater. I can't wait to see one installed. After looking at the photos, a few thoughts come to mind. Though corrugated copper tubing makes quick work, I have noted that it does tend to fail before rigid copper tubing would. The location of the circulating pump creates a scenario where the pump motor could be damaged if the seal goes bad. Instead of a puddle of water on the floor, a fried motor might be the homeowners signal that something is wrong. As for the leak, more investigation might be in order. Was the tubing used light or heavy? The heavy tubing is more durable. The light tubing is what we see in new construction, and this has been the case for 10-12 years now. Fittings, unfortunately, seem to be getting thinner and seem to suffer from poor quality control. Two things of note at the joint: excess solder and excess flux. It appears the joint was not wiped after sweating. Leaving the excess flux in place is not good - it will create pitting and accelerate oxidation, leading to premature failure. I have seen failed fittings due to pitting from the inside. Only once was the joint clean and tidy. That particular fitting failed after 40+ years in service, in a hard-water environment.

Hi, all &

YES indeed - This situation doesn't surprise me at all in my own experience - Hot water constantly circulating just "wears" - all depends on how many bends (90's are much worse than 45's) and how hard /soft (K/L/M copper grade), as to how long things wear-out & it's virtually guaranteed to go eventually...

CHEERS !

Randy,

In Illinois that flex tube is not code. So when I install that new heater we take out the flex tube and hard pipe it in.

That recirc pump has a timer on it so it should not run 24 hours. The timers are usually set to turn on at peak usage times. I am in agreement that that is a poor quality joint with excess flux. But wiping the joint right after being soldered is not a good thing either it introduces air bubbles and debris into the solder joint. A proper soldered joint would have just enough solder to make the joint, and would have been cleaned of any flux run-off after the joint cooled down. When I took my State Plumbing test they subtract 1 point for every joint that has a doblet of excess solder(doblet = small bump up of solder not running down the pipe) and 5 points for any joints wiped while the solder was still hot. If the solder was running down the joint like that they would of failed it right on the spot.

As for thickness of copper most codes state type M is what they want which is the thinest allowed. Illinois code allows Type M, but most cities up in Cook and Du Page county wants Type L copper which is the thicker or medium grade , Type K copper is the thickest which Illinois requires for any underground installation. The color coding is as follows Type M = Red Marking , Type L = Blue Marking , Type K = Back Marking, and if you see Yellow markings on a pipe it is DWV copper which is even thinner than Type M.

Ron, the water supply is city supplied from an aquifer beneath the Columbia River. It is not hard water.

Jerry, the drywall that is not finished tightly against the waste pipe is on a wall between a basement bedroom and the mechanical room.

The wire that Jerry noted is not pinched; it appears to me that the electrician that wired the home didn't provide for the circulation pump.

As for the plug Jerry noted that was not pushed in completely, well, I was in a hurry and temporarily placed it there to show where it connected. I pulled it out after I snapped the photo.

This home was built by people not angels, so I will recommend to the owner to install a leak alert system.

Chip

Originally Posted by Chip Roberson

Jerry, the drywall that is not finished tightly against the waste pipe is on a wall between a basement bedroom and the mechanical room.

Chip,

If the mechanical room is not heated and cooled, then that wall must not only be sealed (top, bottom, ends, all penetrations, etc.), it must also be insulated.

Originally Posted by Chip Roberson

This home was built by people not angels, so I will recommend to the owner to install a leak alert system.

Chip

Chip the best water leak system I have seen in use anywhere is the Water Titan System Here is the site with the Distributors across the US Leak detection, water shutoff valve, water leak detector, water alarms Whats nice is the Shut-off valve can be used with up to 20 leak detectors. Better yet here is the 4 page PDF that explains each part of the system. Leak detection, water shutoff valve, water leak detector, water alarms

Jerry's quote: [If the mechanical room is not heated and cooled, then that wall must not only be sealed (top, bottom, ends, all penetrations, etc.), it must also be insulated.]


Jerry, the mechanical room is in a finished basement. Wouldn't the furnace, which is used for cooling as well, be enough to condition the temperature in the mechanical room so that the partion wall wouldn't need insulation?

Chip

Originally Posted by Chip Roberson

Jerry, the mechanical room is in a finished basement. Wouldn't the furnace, which is used for cooling as well, be enough to condition the temperature in the mechanical room so that the partion wall wouldn't need insulation?

Chip

It would only be considered "conditioned space" if it was within the thermal envelope of the building, then, if small, one could consider it part of the conditioned space, just like one would a closet which has no heat or cooling, however, if larger, then it would need a heat and cooling supply to be part of the conditioned space.

First, though, it must be within the thermal envelope of the building.

I presumed that most basements are not within the thermal envelope, that the bedroom would then need to be insulated around it to be included within the thermal envelope, and, with that being the case (if it is), then that wall would need to be sealed and insulated.

So, the question becomes: where is the thermal envelope of that house? Does it include the basement, and, if so, is that unit sized to include the basement in its heating and cooling load?

On a different issue, don't forget that the bedroom requires 8% of its floor area for natural light (window area) and 4% of its floor area for natural ventilation (operable part of the window area), plus two means of egress, one of which can be an EERO.

Additionally, if the heater if fuel burning, then considerations for combustion air must be made without that bedroom, and then the wall would need to be sealed regardless - insulated or not.

Jerry, the mechanical room is within the thermal envelope of the building; it stays warm in the winter (as long as the electric power stays on) and cool in the summer.

This structure is a day light basement. The bedrooms have 5 ft x 4 ft windows approximately 30 inches off the floor.

What is EERO?

The area in where I live is a great basin or valley, so many upper end home here have walk-out basements. I suppose you live where it is flat with full basements if there are basements at all.

The Columbia River runs right through town. This river has many hydro electric dams, so our electrical bills are cheap compared to what the rest of the country pays. Very few homes have gas furnaces, if they do, they are thinking about changing over to electric heating.

While I am making the repairs to the walls, I will finish around the sewer pipe for the h*ll of it. I have plenty of time these days. I hope this economy improves soon and houses start selling again!

Chjp

Originally Posted by Chip Roberson

What is EERO?

Emergency Escape and Rescue Opening