Plumbing Xperts?
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Topic: Plumbing Xperts?
Posted By: modirt
Subject: Plumbing Xperts?
Date Posted: 12 Nov 2020 at 10:09am
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Having trouble with a hot water circulation pump. Keep getting pinhole leaks downstream of the pump. Appears to be galvanic corrosion, with pump as the source of the problem. |
Replies:
Posted By: Tbone95
Date Posted: 12 Nov 2020 at 11:03am
| What are the materials of the pump and of the pipes? |
Posted By: modirt
Date Posted: 12 Nov 2020 at 11:20am
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Sequence of events....... Short copper riser from hot water tank Grundfos circulation pump installed, with rubber flanges to isolate cast body pump from copper water lines... https://product-selection.grundfos.com/us/products/up-ups-series-100-north-america/grundfos-comfort-system-north-america?tab=models" rel="nofollow - https://product-selection.grundfos.com/us/products/up-ups-series-100-north-america/grundfos-comfort-system-north-america?tab=models Then original install was short section of copper pipes that transition to PVC lines before hot water line leaves utility closet. It is this short length (3 feet) of copper pipe downstream of pump that keep developing the pin holes. One after another. Plumber replaces copper with PEX.....pin hole then develops in next closest copper. Three holes fixed so far......at that point, I turned pump off and no more leaks since. Plumber was at a loss......."I'm a plumber, not an scientist. I can keep fixing it, but can't tell you why it keeps happening".
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Posted By: modirt
Date Posted: 12 Nov 2020 at 11:23am
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Pump might have some kind of short and bleeding a low voltage......only thing I can think of. |
Posted By: jaybmiller
Date Posted: 12 Nov 2020 at 11:27am
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I'd be asking Grundfos what to do !!! Seems like it's 'galvanic corrosion' ( aka 'battery effect') due to 2 dissimilar metals. Obviously BEFORE the pump was installed , no issues, so , yup, call Grundfos PDQ !! Jay ------------- 3 D-14s,A-C forklift, B-112 Kubota BX23S lil' TOOT( The Other Orange Tractor) Never burn your bridges, unless you can walk on water |
Posted By: Tbone95
Date Posted: 12 Nov 2020 at 11:35am
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Thing is, the water is also a conductor, so the rubber flanges don't make the connection isolated. My hot water circulator is brass body, copper pipes, so not that much potential. You have galvanic potential with Fe to yellow metal, with the water as an electrolyte. A short in the pump could add to your problems, but even without it there's an issue. Quick check for a pump electrical issue, is it or could it be connect to a GFCI outlet for power? On my pumps for the wood boiler, if a seal starts to go it won't run on GFCI anymore. |
Posted By: modirt
Date Posted: 12 Nov 2020 at 11:35am
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We bought house 5 years ago.......pump was here then......not sure when installed. But developed 3 pin holes in 3 years before I turned it off. Would leave it like that, but takes long time (30 to 45 seconds) to get hot water to kitchen sink.....distance of about 12 feet. Lines run in or under slab foundation. I'm getting heat from spousal unit on lack of hot water. Just looked and ALL copper pipes and fittings downstream of pump are now green and white from exterior corrosion.
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Posted By: plummerscarin
Date Posted: 12 Nov 2020 at 12:29pm
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Hot water will cause copper piping to fail before cold water. Second, in a recirculating system the friction wears out piping quickly. Third and most important is the copper piping MUST be de-burred as it will cause cavitation in the system which also accelerates wear. After all the copper has been replaced with new, I would look into reducing the flow rate to a minimum setting and if practical add a timer to circulate during high use times of the day. |
Posted By: steve(ill)
Date Posted: 12 Nov 2020 at 12:47pm
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YEA... that pump puts out 6 GPM... You need one about 10 x smaller... If you were moving a quart or 1/2 gallon a minute, that would be all you need.... Your lucky to get 1 GPM out of a faucet, and your moving 6 x that much water !! FRICTION . One way to do it is to have a check valve in your 3/4 inch line with a TEE on each side. Put a VERY SMALL pump between the TEES so it pumps a quart a minute thru the system, and can not flow backward. ------------- Like them all, but love the "B"s. |
Posted By: modirt
Date Posted: 12 Nov 2020 at 12:51pm
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I have heard of cavitation erosion, and that may be plausible, except the first fitting downstream of the pump is a 90* copper L fitting......holes always developed downstream of that....in the straight run copper lines. Not in the L. If that is because the walls of the L fitting are thicker, that might explain it too. |
Posted By: plummerscarin
Date Posted: 12 Nov 2020 at 1:02pm
| Fitting is thicker. But turbulence it creates affects the piping downstream. Would also recommend type L copper as it is thicker than M |
Posted By: modirt
Date Posted: 12 Nov 2020 at 1:24pm
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This is the actual pump, and condition of things as of moments ago...... Sorry the image is upside down......not sure how to rotate it to make it readable. I'm assuming the screw is a flow control.......which way to cut flow back to nothing?   |
Posted By: modirt
Date Posted: 12 Nov 2020 at 1:30pm
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BTW, current pin hole is in short riser between pump flange and L.....the nasty looking little green section..... That is with a water softener too.
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Posted By: modirt
Date Posted: 12 Nov 2020 at 1:52pm
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https://product-selection.grundfos.com/product-detail.product-detail.html?productnumber=59896155&qcid=1135010531" rel="nofollow - https://product-selection.grundfos.com/product-detail.product-detail.html?productnumber=59896155&qcid=1135010531 OK, if I got this right, that is up to a 17 gpm pump with cast iron body? What could possibly go wrong? So what would be an suitable replacement with bronze body?
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Posted By: plummerscarin
Date Posted: 12 Nov 2020 at 2:27pm
| Not entirely sure which way to turn for slowest setting. You should be be able to hear the difference from one extreme to the other. Grundfos has low volume recirc pumps for this application. Check model number UP10-16. Also check out Laing E1. They’re imported but I have installed a number of them with no issues. They have a timer attachment available that is 24hr programmable. |
Posted By: jaybmiller
Date Posted: 12 Nov 2020 at 2:51pm
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their site says it's 'discontinued'.....but is a 3 speed pump though HOW to change baffles me( no documentation). sad thing is I think there's one in the garage 'somewhere'... I agree though a new 'smart' pump, low flow and one that learns your pattern would be better. heck my Well pump is only rated for maybe 6 GPM...... every dang 'head' is maybe 2.5 gpm, kitchn faucet SUX.... try filling a pot......zzzzzzzzzzzzzzzzzzzzz... Jay ------------- 3 D-14s,A-C forklift, B-112 Kubota BX23S lil' TOOT( The Other Orange Tractor) Never burn your bridges, unless you can walk on water |
Posted By: plummerscarin
Date Posted: 12 Nov 2020 at 3:57pm
| The data plate shows amp/watt rating. The screwdriver slot changes the route through the windings. This controls motor speed vs closing a valve |
Posted By: modirt
Date Posted: 12 Nov 2020 at 3:58pm
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On a hunch, I looked and I have my description backwards. What you are looking at on the top of the pump is the return line. Verified that by turning pump on, opened isolation valves and got cold water. You could feel the flow and lines were vibrating......so moving a LOT of water! Return water then flows through pump, into bottom of the tank through drain outlet......and water to faucets leaves top of tank. That way any flow to faucets is not interrupted as cold makeup water enters to replace it. Not sure what that does to the high flow cavitation theory.
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Posted By: plummerscarin
Date Posted: 12 Nov 2020 at 4:45pm
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It boils down to this: Flowing water erodes metal pipe. Anything that affects smooth flow(burrs,bends, tees, etc.) causes turbulence. Turbulence accelerates erosion. Doesn’t matter which side of the pump your on. To that end the will relate a story. Several years ago as service plumber I was called out to a single story motel with 60 rooms. As can imagine that is a long way for hot water to travel from mechanical room to end unit. In the span of a week was called five times to repair a leak in the recirc line. Each time a different location in the same run. It was a straight run. Point is, it just wears out the pipe in relatively short period of time. |
Posted By: modirt
Date Posted: 12 Nov 2020 at 5:19pm
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At this point, that is my biggest concern of all. House built on a slab (really bad idea), with plumbing buried in or under slab. If this is causing leaks at the water heater, where else is it leaking or about to? Only possible saving grace is the rest of it might be pvc pipe. Copper return line switches to PVC when it enters utility closet. Not sure if I want to take a chance on a leak I can't get to. In other words, leave pump off.
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Posted By: DiyDave
Date Posted: 12 Nov 2020 at 5:47pm
Since your copper is all shot, anyway, replace with pex, its cheaper, and don't corrode. JMNO! ------------- Source: Babylon Bee. Sponsored by BRAWNDO, its got what you need! |
Posted By: jaybmiller
Date Posted: 12 Nov 2020 at 5:50pm
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this... House built on a slab (really bad idea), with plumbing buried in or under slab. is really scary !!! copper in concrete ??? yeesh... I'd be planning how to run PEX , 100% if possible.... or move.... Jay ------------- 3 D-14s,A-C forklift, B-112 Kubota BX23S lil' TOOT( The Other Orange Tractor) Never burn your bridges, unless you can walk on water |
Posted By: steve(ill)
Date Posted: 12 Nov 2020 at 5:55pm
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I did in-laws house trailer in PEX to get away from the steel-copper piping in the crawl space.. Took paneling off a couple walls to install some... then ran across the ceiling in bathrooms and laundry room... built a FAKE wood beam to cover the tubes afterward... Worked great.... 45 years old so was a good time to install new faucets / shower head / etc.
------------- Like them all, but love the "B"s. |
Posted By: DMiller
Date Posted: 12 Nov 2020 at 5:56pm
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So long as NO air entrainment and low flow erosion in any water line will be minimal and Take LOADS of time, will generally take a point of a turn to burn thru. Parents house had a recirc pump, pump died twice in thirty pus years living there, NO Piping destruction. Iron or Steel flanges, copper fittings, Plumber here used Sweat Solder Ends for installing our pump(Brass), NON ISSUE in over five years running, lost a timer once so far. Is a Ecocirc ITT unit. Sis in law stays a few weekends a year, enjoys that timer and temp setting side program keep her shower at seconds of delivery time to hot and at 50' from water heater. Did add insulation wrap to the piping after installed as AC time would chill the utility corridor area of our basement and make the pump extended run.
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Posted By: Tim NH
Date Posted: 12 Nov 2020 at 6:18pm
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Looks like from the picture of the 45' fitting, you have high sodium water. Going to a reverse osmosis system will solve your problems. ------------- 1950 WD 1959 D14 1955 WD45 1976 7000 B 207 |
Posted By: plummerscarin
Date Posted: 12 Nov 2020 at 7:26pm
| R.O. treated water should not be be run through metal piping |
Posted By: Tim NH
Date Posted: 13 Nov 2020 at 7:00am
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I agree RO water should not be used copper pipe system. I didn't read the postings close enough. Tim ------------- 1950 WD 1959 D14 1955 WD45 1976 7000 B 207 |
Posted By: Kansas99
Date Posted: 13 Nov 2020 at 7:36am
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Dumb question why shouldn't RO water be ran through copper pipe? ------------- "Thank you for your service Joe & the Ho"-----Joseph Stalin |
Posted By: Tbone95
Date Posted: 13 Nov 2020 at 7:46am
| K99, because the more purified the water, the more it attacks metals and absorbs minerals. RO is extremely pure, and begins to dissolve any metal it comes in contact with and therefore copper would not last long at all. |
Posted By: modirt
Date Posted: 13 Nov 2020 at 8:48am
Good news on this front. Went on a quest and discovered that all risers I can get to coming up through the slab are in fact PEX......hot water lines even wrapped in insulation. So probably safe to conclude the hot water circulation loops are also PEX, so probably OK to replace high flow pump with low flow and be back in business. Comments on sodium........water district is known for having hard water..........so everyone has water softeners. Mine is a Kinetico. It goes through a lot of salt. About 40# per month. My question has always been where does the salt go? Flush cycle water goes into the drains. Does that mean my septic system gets salt.....or what had been NaCl that is now tied up as something else? Lines to faucets that you might drink from.......kitchen and line to ice maker.....remain hard water. That suggests to me a lot of the salt (sodium) must end up in the water domestic use water? Source of sodium? |
jaybmiller wrote:Posted By: jaybmiller
Date Posted: 13 Nov 2020 at 12:19pm
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whew... glad that those pipes are PEX !, sigh of releaf... My weater softener is an 'on demand' style... regens based on actual water uages NOT a 'time clock'. I don't go though mush salt... my 'salty' water to the weeping tile bed.. I was going to plumb it out to a 'drywell', sigh , that was , um, ahh.....20-25-30 years ago.... maybe, one day.... Interesting note, plans for new house next door , say on plans....'NOT to have water softener drain plumbed into septic tank'... You can usually 'dial in' the amount of salt. maybe just reduce by 25%, see what happens to 'soapy hair test' , lotsa bubbles, reduce some more... ------------- 3 D-14s,A-C forklift, B-112 Kubota BX23S lil' TOOT( The Other Orange Tractor) Never burn your bridges, unless you can walk on water |
Posted By: DMiller
Date Posted: 13 Nov 2020 at 2:09pm
| Our softener, Laundry and Kitchen Sink discharges go to a Gray Water Drain field, no need for septic when put bleach and salt down that drain, all biologics DIE in that trench/French Drain |
Posted By: modirt
Date Posted: 07 Jan 2021 at 4:02pm
Epilogue: Went on a quest and found this 2 or 3 gpm pump at a local plumbing supply. If you think $320 is pricey for that pump, I'd agree with you. They also agreed existing 17 gpm pump was running way too much volume. Should have been on a large commercial or industrial site. Anyway, swapped out pump, plus all the old patched up pex and copper plumbing with new type L copper, turned it on and it started cooking. Takes nearly 90 seconds to make the loop, but even that low flow is plenty to deliver instant hot water. So thanks for the helping solve my problem! At least one thing we talked about ended right this year. |
Posted By: Pat the Plumber CIL
Date Posted: 07 Jan 2021 at 9:14pm
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Do not believe that pump is designed for potable water . Bits of cast iron are washing down line reacting with the copper. Need a Grundfos UP10 - 16 . A lot more expensive but brass body. Also believe it is installed upside down. Not sure on flow but should flow to bottom of heater. That pump is designed for circulating water for heating not potable water. ------------- You only need to know 3 things to be a plumber;Crap rolls down hill,Hot is on the left and Don't bite your fingernails 1964 D-17 SIV 3 Pt.WF,1964 D-15 Ser II 3pt.WF ,1960 D-17 SI NF,1956 WD 45 WF. |
Posted By: modirt
Date Posted: 08 Jan 2021 at 12:58pm
On the bits of cast iron, that was confirmed when I starting purging air from the hot water lines. Bathtub in guest bath that rarely gets used, dumped a bunch of what looked like fine iron particles, plus some pink water, which may have been rust forming in the line leading to that faucet. So I'd agree.....between the high volume pump, thinner type M copper lines, and possible corrosion from mixing metals, that whole thing was a mess. Would be interesting to know what the thinking was of the guy who installed it. Was like that when we bought the place. Been trouble the whole time we have been here. We did replace with the Grundfos UP10-16 pump with brass body. Is working well. |
Posted By: plummerscarin
Date Posted: 08 Jan 2021 at 6:29pm
| My guess would be price first. Glad your system is working well |
Posted By: Coke-in-MN
Date Posted: 09 Jan 2021 at 11:59pm
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Seems rather than a timer or along with a timer a heat sensing thermostatic switch could be added so it would turn on at some low temp and turn off when hot water is sensed on line temp equaling water at desired heal content in the return line . ------------- Life lesson: If you’re being chased by a lion, you’re on a horse, to the left of you is a giraffe and on the right is a unicorn, what do you do? You stop drinking and get off the carousel. |
Posted By: plummerscarin
Date Posted: 10 Jan 2021 at 8:31am
| Laing has that type you mentioned. I put one in for my cousin a couple weeks ago. It's a point use type. Went in cabinet under kitchen sink where there is a 120v outlet already. Has 24hr timer as well as temp sensor. He loves it. It works by pulling hot water from the hot side and sending to the cold side back to water heater and shuts when temp reaches 95 degrees. Granted you might have to wait a bit for cold water to fill a drinking glass but for his purpose it works great and is planning to get another for a vacation home. |
Posted By: modirt
Date Posted: 10 Jan 2021 at 11:47am
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Took me a while to wrap my head around that one, but can see how it would work. A way to graft a hot water circulation system onto a house that was not plumbed for one when built. But other than that, can't see the advantage. Pump on timer or temp sensor would work either way. This house, which was plumbed for the circulation system has a first level loop that goes to all hot water faucets on the ground level. Two bathtubs, two bathroom vanities, plus kitchen. Instant hot water to all. But now that this one is working, we are finding the same issue with the warm cold water. Cold water lines apparently plumbed parallel and close to hot water lines, which despite being insulated, over time will still warm the slab they are running through. So hot water is circulating, but cold water is stagnant until used, so instead of staying cold, cold water in the line is being warmed to slab temp, just as a stagnant hot water line would get cold. What I have discovered, however, is how pleasantly warm it is to be standing on the section of floor where those lines run. This is the first slab on grade house I've ever lived in, and I must admit, I'm not a fan. But if I was going to build one, it would be great to utilize the slab with a hot water radiant heat system.
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Posted By: Coke-in-MN
Date Posted: 10 Jan 2021 at 2:14pm
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they also make a small point of use hot water heater one can install under a sink and runs on 110 v - friend has on in her kitchen so has instant hot water . Have thought about one of them . ------------- Life lesson: If you’re being chased by a lion, you’re on a horse, to the left of you is a giraffe and on the right is a unicorn, what do you do? You stop drinking and get off the carousel. |
Posted By: DMiller
Date Posted: 10 Jan 2021 at 3:26pm
| Put in a Keep Warm loop in our Hot Water system when built, Laing pump and timer, can adjust for Water temp on return side for shutdown. Insulated the Outbound pipe and return leg, runs 1/3 the time as uninsulated. Cool water when first turn on shower or bath faucets, takes but moments and already warm, at temp less than a minute in either upstairs bath. |
Posted By: Sallymilr
Date Posted: 22 Apr 2021 at 4:40am
| I am not so strong at drain blockages. From my point of view, I believe that these are the worst plumbing issues that can appear. I got a massive headache due to this problem. I tried to solve it with my own hands but with no chance. So, I decided to call the guys from one of the http://https://www.wilcoplumbing.com.au/blocked-drains-sydney/" rel="nofollow - best plumbing services in Sydney . They sent me a team of experts that resolved all the questions regarding plumbing needs. I am very thankful to these guys because they saved me from big wastes. Also, they held a lot of my time. |
Posted By: plummerscarin
Date Posted: 22 Apr 2021 at 6:44am
| The worst is a clogged urinal drain. That's all I got to about that |
Posted By: joannsabki
Date Posted: 08 Sep 2021 at 9:41am
| Oh, I've never been able to do a job with pipes. I always called http://https://plumbingservicescolumbiamd.com" rel="nofollow - Emergency plumbing because once I tried to make a pipe myself, I then had the floor of the house in the water. Since then, I no longer do plumbing. And apparently, you have the same situation, haha. Friend, don't worry so much. In my opinion, it is better to call professionals and let them deal with such things. Yes, you will have to pay money, but at the same time, you save your time and nerves. Well, everyone has their own. I just expressed my opinion on this matter, and I hope someone shares my opinion here. |