A long story has brought me to this point but I will try to make it brief. If maore details are needed I’ll add them.
In 1997 I had a new home and workshop built. Since the home was uilt I have had nothing but problems with the GSHP installation. Mostly water flow faults or high presure faults. The installation contractor has attempted to fix them each time and the system will usually run anywhere from 3 months to a year with no issues, then it faults again.
The most common cause for the faults is the groung loop circulation pumps are failing, either the bearings are going bad or the motors burning up etc. I have a total of four pumps in the system and three of them are currently too hot to touch, (this has usually been due to them being in essentially a locked rotor state). Sometimes you can get them spinning with a screwdriver in the slot on the pump shaft but ot always.
We are ten years into this system and I can’t get a decent diagnosis of what is wrong. The mfg will not speak directly to the end user, the installer, while he has “fixed” it numerous times, he has obviously never found the root cause of the problem. To his credit he has not charged me for all the service calls he has made, but then again, the system has never worked properly. I beleive I am at the end of his rope and I will be on the hook for all future repairs.
I guess I don’t really know where to turn at this point. I am talking to other techs to try to get it resolved but I can’t get the orignal installer to give me the details of what was done previously to repair the system, or the details of the ground loop configuration. Without this info I am at a severe disadvantage when talking to new service people.
If a new guy finds that the issues are due to the original system eing designed improperly do I have any recourse against the installer?
I’m a reasonable guy and understand that things aren’t always easy to troubleshoot, but I am concerned that there is a serios design problem and I’m going to be on the hook for some major repair bucks.
Any insight would be greatly appreciated.
Replies
It should be fairly easy to install ports for measuring pressure on the ground loop. If the pumps are failing due to excessive resistance in the ground loop, that should show up as excessive pressure.
(But I'm wondering you have more than one pump. This is apparently a more complex system? Or do you have multiple systems for zoning, with a separate loop for each?)
I have a total of four pumps and two units, one for the house and one for the shop. They are on a combined loop. I have suggested installed temp and pressure sensors on the loop in a couple locations so I could monitor what is happening during different phases of operation.
One of my other concerns is that there are no check velves in the system which, to me, seems like it gives an opportunity for the pumps to fight each other. I have suggested check valves after the outlet side of the pumps and was told it was not necessary.
This is a little more complex than a single unit installation but they tell me they have many systems set up the same way with no issues.
These circulation pumps should last for years and no one can give me any idea why they are failing.
Bell and Gosset pumps?? Or what type/make. All the details you can provide would be a help, such as types, one-line diagram of the system, pipe sizes and lengths. Very hard to troubleshoot on the minimal info given.
Have a few similar pumps in some of my systems, the B$G need to be oiled every six months at a minimum or the bearings can freeze.
A flow problem cannot cause a locked rotor condition.
Have had locked rotor problems on B&G and similar pump due to one of the springs breaking on the coupling.
Also have had water drips getting into the centrifugal switch and leaving the start winding ON all the time, fast overheat and motor failure.
If the motor/pump assemble is not mounted almost perfectly horizontal, bearing failure will also occur (one time I mounted one vertically, it failed within a few months)
I beleive these are grundfos pumps but I'll have to look when I get home in the morning.
I don't beleive the flow problem is causing a locked rotor but possibly disrupting proper flow enough that it is causing premature bearing failure.
I may have to sketch something up and scan it to show how the system is plumbed.
I beleive these are grundfos pumps
You're saying that Grundfos refused to talk with you? I can't imagine that from my experience. I've found them excellent, particularly when I had a problem.PAHS Designer/Builder- Bury it!
Water furnace is the one that refuses to talk to me. The pumps are installed in water furnace flow centers. I may give grundfos a call.
You learn a lot about a company by how they handle end-user problems. Water Furnace... I'll try to remember, not that I expect to ever want a GSHP.
I'm a Grundfos fan, but haven't spoken with them lately. My problems were with a well pump, sold two wrong ones by a drillers' supply (that's the only thing they do). System still didn't work. Took Grundfos 2 minutes to diagnose and solve the problem over the phone.PAHS Designer/Builder- Bury it!
From your description, it sounds like the major problem is with the pumps. I will add a couple of comments that are more from a pump point of view than a gshp point of view
Every time you have multiple pumps on a common system, they should have check valves.
I would start with that.
Every time you have multiple pumps on a common system, they should have check valves
That is my feeling too but every time I suggest it I am told it is fine without them. Frustrating to say the least.
Tom, if you make suggestions and they say that can't be it, but they still can't diagnose a problem.........sounds like they're not trying very hard.
Do you feel the installers are taking you seriously? Perhaps if you threaten them with legal action they will step up their concern and do what needs to be done: call in the manufacturor, or an engineer for a consultation. It seems as if you have a problem that's over their heads, they're not taking responsibility for it and they're waiting for you to go away.
Ed
Edited 8/18/2007 7:44 am ET by edlee
The installer has had the mfg out here twice, although both times were scheduled on very short notice and both at times when I was out of town. I have considered legal action to the point of briefly consulting with an attorny but his take on the matter was that I don't have much of a case.
I can't get the installer to try anything much different than installing new pumps or changing the pump configuration slightly. Obviously none of this is working and a better solution is needed. Finding the right person to troubleshoot this is the real dilemma. Water furnace has been abosolutely no help and they are the ones that refuse to talk to the end user.
I beleive the installer wants to fix this, it's had to have cost hima pretty penny over the years in service calls that he has never charged me for. I just don't have any faith that they can fix it.
Tom,
In addition to all the great advice you have already recieved........
w/o knowing more about the system, I would take a guess the motors are simply too small for the application, w the system set up as is ( not to say "as is" is a correct set up ).
You say the pumps "lock up". Are the pumps breaking or are the motors failing?
Check the amp draw on the motors. Compare it w the motor name plate.
Harry
Here is a bit more info.
The current flow centers that are installed are shown here http://www.geocomfort.com/Products/Residential_Products/accessories/Geo-Flo1028DualPumpFlowCenterSpecifications.pdf. These have the type UP 116 116f 220v cast iron pump installed. Warranty looks to be five years on these pumps and I have never gotten a year out of them.
In the past I have mainly relied on the installer to fix this issue and as I have said he hasn't charged anything to do this, and each time he is sure the issue is resolved, then nearly a year later we have a failure and we are without AC (or Heat in the winter) for days in the middle of a GA summer. Time fo a different plan of attack I guess.
I have an independant guy coming onday morning to take a look at the whole system and see where we stand and what his feel for the total design of the system. The installer is sending his crew tuesday so I should have some notes to go over with them and maybe a new plan of attack.
I also hope to learn enough about the system to effectively service and troubleshoot problems myself, or at least be able to monitor it for developing problems. I'm an aircraft mechanic by trade so I have a good technical background. Getting anyone to teach me about the maintenance and servicing of this system has ben nearly impossible thus far. The guy coming monday sounds like he may be willing to work with me in that regard. A refreshing change for sure.
Here is a rough sketch of the current loop configuration inside the house. There is a valve installed between the water furnace the flow center on each unit to adjust the amount of flow to that nit. The 5 ton valve is wide open and the 2 ton is partially closed. I have no idea what method is used to determine the position of these valves. There are no pressure or temp guages installed i the system anywhere to assist in monitoring operation.
I don't know the outside loop configuration, that is a big bone of contention with me as it really limits the amount of info I can to anyone else that is coming to evaluate the system. I intend to get these documents as well as any previous service history this week, even if it means a letter from an attorney demanding the info.
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Since your have dealt with "pros' on the problem, try asking the questions at hvac-talk.com.
Make sure you come across as a bewildered homeowner, dont mention DIY <G:>
You may get some good suggestions for what to ask your "pro'" contractors.
Good Luck.
When I asked about details in an earlier post, it was VERY specific details, such as pipe sizes and lengths, flow rates, etc. Apparently that data is not available to you?
As others have said, if you could get the motor currents and power factors (or are thaey actually 'locked' or stalled as implied earlier)
I don't currently have the details you need. I'm trying to get those btu that request always meets some resistance, which i don't quite understand. As far as the pump motors they are getting power, but not turning, IE frozen. The grundfos pumps have a small screw on cover that allowas access to the motor shaft and when that cover is removed you can see if the pump is turning or not. These ( 3 out of 4) are not. The pumps that are not turning are also extremely hot, too hot to put a hand on. When working properky you can lay your hand on them with no problem.
I wonder if the pumps are 240V units, on a 120V circuit? Or perhaps they need an external starter but weren't installed with one.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
No starter needed
not turning, IE frozen
Wow.
I have a hard time visualizing a flow problem freezing up a cenrifugal pump, have never seen it happen with water.
Grit or other foreign objects mentioned by other posters jamming the impeller is a possibility, also improper alignment or electrical problem, such as failure of the start winding switch or capacitor.
I notice you dont have info on your profile as to geographic location (click on your name in the header to add), cant recall if you mentioned in a previous posting. If you just happened to be in Seattle area or someplace I travel to often I'd come take a look gratis just out of curiousity.
One thing for you to try when you spot a frozen motor is to see if you can apply extenal mechanical force to get the rotor to move or start spinning. (Easy on B&G pumps, not that familiar with Grundfos, but dont think you can get to anything rotating??) Mechanically locked means a jam on the impeller, if you move it mechanically and it starts spinning, the problem is likely electrical.
If it were my own system, one of the first things I'd do would be to pull the motor off the impeller housing and look for foreign debris - you installer should have already tried that???
Water flow problems on centrifugal pumps simply do not freeze up the impeller (unless the water freezes) - check for crap in the lines or a start circuit failure, which is unlikely on multiple pumps. Call Grundfos for similar case histories as Tom suggested.
There is a famous aircraft crash over a decade ago that was the result of the same technician installing an o-ring on both engines of a plane incorrectly, so that both engines failed*.. That is another thing to check out - were ALL your pumps installed incorrectly or was there a failure to purge all the lines of debris?
*multi engine aircraft engine maintenance is now done by a different technician on each engine to avoid that type scenario.
You can get to the motor shaft on the grundfos pump and try to get it spinning, there is a slot on the shaft for a screwdriver. I can't get these to turn. I'm am thinking that it is a bearing failure in this case. I never get the opportunity to inspect the pumps when they are swapped so I don't know what the cause of any previous failures is.
I'm quite familiar with the aircraft engine maint scenarios. We deal with that every night. I review all my paperwork at the end of each night to make sure we didn't have a dual exposure situation.
I would imagine all the pumps were installed by the same tech and I know it was all flushed at the same time so it is a possibility. The problem is this happens so often that I am led to bleive it is a systemic/design failure, not just a servicing issue.
I'm located in Georgia.
Edited 8/19/2007 1:29 am ET by TomW
These are wet rotor pumps. Not like a B&G 100.
Update:
Had a ground loop designer/installer come out today to look at the setup. Super guy. Didn't talk down to me like most every other technician does. We went over all the issues I am having, confirmd that at least one pump is failed. We didn't get into any actual temp/presure measurements since the system is in a failed mode already our readings won't be very acccurate.
I brought up the idea of ading check valves and since he is relatively new to this and has only dealt with single unit systems he said he would research it and get back to me but he understood why I thought it could be a problem.
We dug out some pictures of construction where I hade taken pics of the loop installation so we were able to go out and measure the approximte length of the loop an he could get a rough idea of whether the loop was sized correctly. It appears to be correct.
He gave me a list of things to ask the installer for, that should have been provided at the time of construction, inclding a site diagram and a tag that specifies the specific gravity of the glycol solution in the loop. This apparantly can have a great effect on the flow characteristics. He also said I should ask for a copy of the initial circ pump head loss worksheet, this would be very helpful in determining if there has been a reduction in flow of one of the loops.
He showed me where I need to monitor temperature and pressre of the loops. I will get some probes and start documenting this for future trouleshooting purposes. He also suggested getting a water sample when the pump is changed and checking the specific gravity of the fluid.
All in all very helpful and informative. A real credit to the profession. He gave me some printed trouleshooting guides and some contact info ofr water furnace regional reps and other local loop installers in case I wanted other opinions or help. He left and said he would get back to me on the check valve issue after some research.
About four hours after he left Igot an e-mail stating that he had found some documentation about the check valves and that they are required in multiple unit systems that share a loop to prevent short circuiting. Basically if there is a difference in demand between the two units, (there often is since the shop sytm is not always on and it is set to much different temps and is 1/2 the size), there is a possibility that one heat pump will circulate through the second heat pump, bypassing the gound loop. This will lead to much higher loop temps and is probably causing the pumps to fail due to overheating.
The installers crew will be here tomorrow so I have a lot to discuss with them and hopefully we are headed towards a resolution.
Hopefully I will have another positive update tomorrow evening.
Hey Tom
Can you send me the contact info for the latest ground loop designer/installer? How about the original installer too?
TIA
I sent you the info John.
Today's update. the original installer's tech came out today and confirmed that we had three pumps failed. Other than that no new news. The tech had no opinion on whether or not we should have check valves installed or not The owner, whom I spoke on the phoe with later in the evening is adamant that it does not need the check valves installed and that we had them installed in one of the previous configurations and was instructed by water furnace to remove them. I don't recall them ever being there but it is possible although I remember asking about installing them previously.
He is supposed to be getting me copies of everything in my file.
Back to square one for now.
ARRRGGGG!!!!!
Something to try that may prove nothing.
Take the cap off the end of the pump and turn on another pump. See if the pump turns backwards. If the shaft turns freely by hand, and doesn't turn, check probably not needed.
What is there in the ground loop for removing air?
There is nothing in the ground loop for removing air. I beleive it relies on being properly flushed/purged whenever serviced. If there is something available to automatically remove air I would be interested.
I have since spoked with another loop contractor with 18+ years of experience and he also beleives the check valves are necessary.. I don't see that installing them could posibly hurt anything as flow is only supposed to go one direction anyway. maybe I am missing something.
I am trying to get in touch with water furnace directly although that has proven nearly impossible in the past.
Here is a link to the servicing and flushing procedures for the system if you are interested.
http://www.geocomfort.com/Products/Residential_Products/accessories/IM1961_GeoLinkFlowCenterInstallationManual.pdf
Like I said before, two things kill a wet rotor pump. Grit and air. And getting air out of a coiled loop is tough.
Can you hear water rushing through the pipes with the pump running. If you can, you have air.
Can't normally hear any water running through them.
What about when the motors are running (realizing that that isn't "normal") ;)
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Edited 8/22/2007 9:43 am by DanH
When the system is running, pumps on it is virtually silent so I don't beleive air in the system is the problem. I suppose grit is a possibility, but the system is closed so I don't know where it would be coming from. It has been flushed several times and the water has been sent out to be tested but I don't know any of the results of said testing. As the homeowner I am left completely in the dark on just about everything.
I wish I knew of a way to get this thing resolved but I really feel like I'm at the mercy of the original installer here.
Tom This may seem like a dumb question , but could the return and discharge lines from one flow center be crossed. Discharge from the 5 ton to the return of the 2 ton and visa versa . Red
> The most common cause for the faults is the groung loop circulation pumps are failing, either the bearings are going bad or the motors burning up etc.
What other kinds of problems have you had? Maybe there's a common thread between them.
Two things wil kill a wet rotor pump. Grit. Assume your fluid is clean.
The second is air. Any air that gets trapped in the can will kill the pump.
And purging a ground loop can be tough.
Have you been adding any water to the loops?
I have not added any water to the system. That has been one of my concerns, that the system has not been getting flushed/bled properly. Of course I don't have any way of knowing if this is the case.
These particular flow centers were installed in 04 replacing the original water furnace flow centers. I beleive they use the same type of pumps.
I assume the fluid is clean, once again, I don't have any way of checking this but there is no reason it shouldn't be.
Tom: Keep in mind that your pump is failing. I would ask your installer to replace a pump with you paying for the replacement pump. Then disassemble the frozen pump. You're either going to find the pump full of crud (my vote) or frozen bearings from an over-temp. This is the information you HAVE to have to figure out what's wrong. Stop waiting for the installer to have a "moment of brilliance".
Some notes:
1) make sure the pumps are rated for high-temp operation and the
voltages are right (test these!)
2) the system MUST have anti-backflow valves or it won't work properly
and can't be flushed properly!
3) next time they flush the system, make sure they flush everything,
and in both directions! If they just flush by replacing the pump
with the flushing apparatus they're just running water through the
other pump and not through the ground loop (or vice-versa).
Let us know..
Brooks
Edited 8/22/2007 3:11 pm ET by Brooks
Where would the "crud" be coming from? I beleive this has been a cause of failure in the past. Supposedly they sent a set of pumps from my home to grundfos for analysis but I don't know what the results of that were.
Unfortunately it is getting to the point of me being in an adversarial position with the installer. My intentions are to cooperate in finding a solution to the problem but I beleive as soon as I have anyone else touch the system my warranty rights will be null and void with the original installer. I was handed a bill today for ~1500 and 'm sure you can guess what ny position is on paying that. I don't know as of yet if I am expected to but they were out here just one year ago and the replumbed everything inside the house and replaced at least two pumps.
I beleive we have a design or servicing issue but I really don't know how to get it fixed short of cutting all ties with the original guy and having checkvalves and a pressureized failsafe unit such as the one here http://www.flowcenterproducts.com/Accessories.htm installed. This unit should remove any air that is still in the system even after flushing and I would be able to esily monitor loop pressure.
I may even have to get my own flush cart and handle all the maintenance myself. I can at least get the pumps themselves covered under the warranty and labor will be my own. I certainly can't afford to spend 1500 a year in upkeep.
As far as flushing the system I have been told by a couple respected people in the indusry that flushing this systme properly should take at least acouple of hors to ensure all air is out of the system, especially if the possible cause for pump failure is air. They were only here for a little under two hours working on the system which included replacing three pumps and flushing the system which was only done from one location. I don't beleiveit can be properly flushed that way, especially with two flow centers installed and no check valves. I wasn't able to witness all of the flushing procedure so I don't know exactly how it was done. The tech that was here certainly wasn't interested in answering any questions or having his methods questioned.
If there is "crud" in the system that is causing the failures who has the liability. The only person that has had access to the system is the installer. He has taken water samples and sent them out and they cane back fine so I would think that should be a non issue at this point.
Do I just cut all ties and start maintaining this thing myself. I paid a lot of money for this system up front and have yet to have a solid year of uninterupted service. The only thing I can fault is either a design or servicing issue which IMHO is squarely in the hands of the original guy.
I'm willing to pay for the additional parts to have the check valves and failsafe nit installed by him but Idon't think he will be agreeable to that even though every industry expert I have spoken with aggrees that check valves need to be installed.
Well, if you've been handed a bill for $1500 and don't think you should pay it you've just arrived at an "adversarial position". It doesn't look like you have any further "warranty rights". And if someone showed up at my place and "certainly wasn't interested in answering any questions or having his methods questioned" I'd have made my requirement of courteous information clear to him!There's no way one can properly flush a multi-path system, no check-valve system from one point! SO if you originally had an impeller failure the debris are still there...To answer your question about where the crud could be coming from, the ground-loop could have failed deep under and be pulling in grit...I'll stick with my original post: get a bad pump replaced and tear down the old one. You're just guessing if you don't know why it failed. Get the system sorted out, and sue the installer if you think its appropriate.Let us know - this is getting be be like a Perry Mason novel!Brooks
Well, if you've been handed a bill for $1500 and don't think you should pay it you've just arrived at an "adversarial position". It doesn't look like you have any further "warranty rights". And if someone showed up at my place and "certainly wasn't interested in answering any questions or having his methods questioned" I'd have made my requirement of courteous information clear to him!
It has not yet been determined whether or not I will have to pay the bill, hence why I don't know if I am in an adversarial position at this point or not. My preference is to work with them to solve the problem.
The tech that came out today has never worked on my system and probably isn't used to homeowners asking technical questions about what he is doing. I know he is not in a position to tell me yes he thinks it needs check valves or a pressure failsafe unit or no it doesn't That would put him in an adversarial position with his employer.
I am trying to schedule a sit down meeting with the owner of the company to explain my concerns, and find out exactly where we stand warranty wise. I also need to have all the documentation of what has been done previously.
A lawsuit is exactly what I am trying to avoid. The installer is holding all the cards at this point since he has yet to give me any documentation on what has been to in the past. I have zero proof of what has been done. I have been too trusting of him to fix this and now am finding myself in a bad position should it come tothe point of actually suing him.
The fact is it would be cheaper and easier for me to just drop him and start maintaining it myself, but that pretty well lets him off the hook for a system that hasn't worked right since day one.
Edited 8/22/2007 3:59 pm ET by TomW
Edited 8/22/2007 4:05 pm ET by TomW
Fair enough. I'll leave you with the comment that the pumps are failing, and tearing down a failed pump should provide a lot of information regarding the cause of the failure.I have another thought (I have an hour drive home each night - I have lots of time to think!). I was wondering about the temperature of the upcoming water, and whether or not this is a pressurized system. It occurred to me that it its not a pressurized system, and the upcoming water is fairly hot, the low-pressure area at the center of the pump impeller may be low-pressure, high-temp enough for the water to flash into steam, stalling (in terms of cooling flow) the impeller and heat-damaging its seals and bearings.As I said before, let us know, will you? Its intriguing...Brooks
I am in the proces of getting temperature and pressue probes so I can start recording operateing data so i will be able to give some info in that regard soon.
I am hoping we can have one of the pumps sent off to grundfos to determine the cayse of failure. I would hope I wouldn't have to "buy one of teh pumps back in oreder to open it up. As far as I know the only thing they have to return to receive warranty payment from grundfos is the faceplate.
Like I said, my preference is that this is a cooperative effort to solve the problem, thus far the installer has not bee real receptive to that idea. I don't know why.
This is a pressureized system.
Edited 8/22/2007 6:38 pm ET by TomW
Update, met with the installer today and the pumps have been sent to water furnace and/ or grundfos to determine the cause of failure.
We went over the service history and he gave me a printout of all previous service visits. It looks like we have had a minimum of 18 pump failures over the years. Some entries show a single pump replace ment but I beleive some of those may have had two or more replaced.
The loop has been flushed several times and the water completely purged and replaced a couple times.
Flow centers have been replaced.
Check valves were originally installed then removed per water furnace after a site visit in 2000.
Water sample was taken and tested in 05 and 06 apparantly with no issues
We are now waiting for a response from water furnace on the cause of failure and a recommended plan of action.
The installer has suggested going to a commercial style pump (grundfos cr http://net.grundfos.com/doc/webnet/cr/int/pdf/cr_innovation_inside.pdf ).
This would be a single pump installation and to me appears to be the equivalent oh hitting a nail with a sledgehammer. I doubt I would ever have a pump failure with this arrangement but they are talking about install costs around 2k (that may even be partially subsidized)
I plan to look at that option but I'm a bit miffed a water furnace. These problems have been ongoing since 1998 and I feel like they have left the contractor holding the bag. They can't find a fault with his installation of cite a cause for failure, yet he is still the one coming out replacing parts free of charge.
I am also not happy about throwing another 2k at a system that hasn't worked correctly since it was installed (or at least not reliably) I'd like to see water furnace credit me back for the original flow centers and pumps and pay the difference for the new style. Of course there is no guarantee the new style will fix it but it is a hell of an upgrade pumpwise.
Looks like a bit of a waiting game for now.
That's not a sledgehammer, more like a jackhammer mounted on a skidsteer.
And trust me, those pumps can fail too.
18 pumps????????????????????
They ain't getting all the air out.
And moving too much water is a bad thing.
Edited 8/24/2007 7:34 pm ET by rich1
Water furnace has been on site for a couple of the time it was flushed. The owner of the company was here as well a couple time and assures me that it is not air. After changing that many pumps I'm pretty sure he wants this fixed.
The system is silent when operating. If there were air in the system would't it make some kind of noise. This company has lots of geothermal systems up and runing and none have the issues mine has. The owner and service manager don't know what else to do at this point and having, me, mr homeowner, tell them they have air problems ain't gonna fly. I've asked about it and he assured me that it's not the case.
I know when you service it with the flush cart you can tell if the air is removed y deadheading the pump. I am old that when they do this they are not geTting the level to drop in the tank, thus there is no more air in the system to compress.
I would love to beleive it was something that simple, but that would mean that every single tech that has serviced this system has done it wrong. The loop is not losing pressure so there are no leaks for air to get in.
minimum of 18 pump failures over the years
OH cr@p,
sorry for the profanity, but that is about 16 more failures than the FAA would have tolerated on any airplane or the military at a critical installation without a full up root cause analysis investigation. WF and GF should have responded long ago.
Thanks for the update, keep us posted. You can write a paper for AIAA or IEA heat pump conference once the root cause is determined.
I always have slow down and look closely whenever I have a call on parallel pumps, they can be tricky. They need perfectly matched piping to work properly without losses. If you have a shutoff valve after each pump there is a simple test you can do to check if a pump is being deadheaded by flow. A pump discharging into a pressure equal to or greater than it produces itself is like pumping against a closed valve. Use a digital ammeter on each pump in turn with all pumps running and record the readings. Then, deadhead a pump by closing a valve, and take another set of readings. Open that valve and close the next one, repeat. 4 pumps will get you 5 sets of readings etc. The amperage will drop on a deadheaded pump. A deadheaded pump will fail prematurely due to overheating since the flow of water provides the cooling. You didn't say if the failures were limited to one or two pump positions ar if they were all failing.
We have had failures in all 4 positions. There are no valves at the pump outlets that would provide a means of doing the check you described.
Edited 8/25/2007 12:24 am ET by TomW
If all of the pumps are the same EXACT model then the amp draws on the pumps should match. The volume of water flowing will correlate to the amperage on the pump. If you were to have a means to "throttle" the water flow you could watch this and plot it on an x-y axis and you would have a pump curve. You can still use this knowledge to help you troubleshoot your water system, just requires some ingenuity on your part. Try taking readings and then cycling through different operating scenarios while watching the amp readings. A drop in amp draw is a drop in water flow. It won't hurt these little pumps to deadhead them for only a couple of minutes so don't be afraid to try it out. This will help to establish if there is a water flow or piping issue or not.
You will have to use an ammeter with at least tenths and preferably hundredths resolution since the amps are so low on these pumps.
Let us know what you find out.
Tom,I don't have a heat pump and I'm surely no expert...but I do have a few observations:My understanding is that flow centers consist primarily of two pumps in a series, push/pull configuration. Seems to me that if you lose one pump in a flow center, it might obstruct the flow enough to cause a problem with the other pump. It depends on the pump design, but it might be a question to ask. Either way, though, if you lose a pump in one loop and the other loop keeps running, the two pumps could overpower the remaining pump in the first loop and stop the flow, which would cause a problem for that pump as well. Seems like one failure could lead to another, unless you catch it right away.If you have the same flow centers on both loops, they would both be sized for the 5 ton loop. The flow valve on the 2.5 ton loop would be - as you noted - the one that was throttled, because that loop would not need the full flow capacity. But you'd have to ask them how they came up with the setting they used for the valve.Unless you always run both loops simultaneously (and you say that you don't), I agree that you'd probably need check valves to keep from short circuiting through the loop that's idle. And as Brooks noted, the same short circuiting would make flushing the system more difficult. You could get around that manually by plugging one of the flush connections on the opposite flow center and switching its associated three-way valve over to block the flow. But that's not covered in the manual, and it probably doesn't get done.I think the pressure and temperature data you will be collecting will most likely be the key. If the system pressure gets too low or the temperature gets too high, one of the pumps may cavitate, which is worse than having air in the system. And as your ground loop designer suggested, it would also be good to know you've got the proper glycol concentration in the system. If it's gotten diluted from all the flushing and filling, that could also contribute to cavitation.Finally, back on the flow control valve, I would think the place to put it would be between the flow center and the ground loop rather than the water furnace and the flow center. Placing it upstream of the second pump decreases the pressure at the suction and increases the possibilities of cavitation, especially when you're in cooling mode and picking up heat from the water furnace.The real answer may turn out to be none of the above, but it's an interesting puzzle, and I'll be looking forward to seeing what you end up with.Good luck,
Dan
bump
pumps have been sent to water furnace and/ or grundfos to determine the cause of failure
Any feedback yet, would love to know the true cause of this situation.
Nothing yet. I've been out of town but no one has called about it. I'd love to get to the bottom of it as well.
another bump re grundfos fail analysis?
Still no word back yet. The pumps were going to waterfurnace first and then to grundfos. My experience with water furnace customer service is not good at all. I will be calling this week to see if any progres has been made.
I didn't address the pump question you had. The pumps installed in this system are very common to geothermal systems grunfos up26-115f. This si a 220pump and the voltage going to them is correct. (i have checked it).
Both geo-flo http://www.geo-flo.com/New%20catalog%20pages/2005%20GPM-2%20FOAMED%20PDF.pdfand flow center products http://www.flowcenterproducts.com/docs/GFM-116-2.pdf use the same pumps that I have and other industry experts I have spoken with don't beleive it is a pump sizing issue, in fact Ron Klaty, the owner of flow center products beleives I have a good quality flow center (not his product) installed and that the pumps are in the correct application.
Tom
Go to the 'wall' on heatinghelp.com and post your problem. The guys at heatinghelp.com mostly do raidiant floor heating and steam systems, so their all familiar with how to diagnose pump and flow problems - if they can't diagnose and give you a course of action to take, no one can.
The guys on the Wall at Heatinghelp.com are the best in their field.
Good luck.
I just wanted to give this thread a bump, and see if there had been any progress in getting the problem solved.
Kenny
Unfortunately, no, we haven't made any progress. I called water furnace a couple of weeks ago and to find out what they found with my pumps and they said they were testing my water to see if there was something in it causing the problem. I asked how that was possible since all that was sent was the 3 pumps. No water samples had been taken. They said that was all they had on record and that they would get in touch with the installed.
I called the installed the same day to see if they had heard anything back about the pumps and they said that they were meeting with water furnace the next week and would get back to me.
Since then a water sample has been taken and sent to them but I still have no idea what has caused any pump failures. I am very skeptical of the notion of the water quality being an issue. It is serviced from my home water supply which is excellent. I have no issues with any other plumbing fixtures and have a hard time beleiving a grundfos pump could be fragile enough to fail that often from poor water.
Hey Tom,
I've been following this thread since inception and it's hard to believe the run-around you're STILL getting. It's like a fictional lead-in to some article about bad customer service horror stories.
I mean, it's a mechanical system that has a limited set of variables. I can't help feeling that if someone knowledgable spent time investigating, they'd figure it out.
It's not like they're trying to cure cancer.
Ed
Edited 10/9/2007 6:56 am ET by edlee
With cancer the patient eventually dies and the problem goes away. This patient is refusing to go away and it's irritating them.
If your view never changes you're following the wrong leader
Well, I got a call from the installer today, more correctly from the service manager. He is relatively new and appears to be taking a much more proactive stance. He and the owner went to water furnace and discussed my system. We still don;'t have any definitive answers but they are coming out tomorrow to replace all fours pumps with new units that will be warranted and they are completely purging the system and replacing the water. Apparantly water frnace was concerned about the ph of the water crrently in the system. I do know that having the wrong ph can cause the viscosity to be too high and will case pump problems. I don't know if I'm convinced but they are at least trying something.
They are covering the last set of pumps as well so the 1500.00 bill I have been fighting is out of the picture. I have hopes that the new service manager will stay on top of the issue until it is resolved. My real disappointment is with water furnace though since they have essentially ignored the problem for 10 years and I am still basically unable to speak with anyone there without being talked down to.
A link that might help you to dial in on the problems.
http://www.proctoreng.com/reports/invest.html
Thanks for the link. I wish that it was a more recent study. It appears that many of the issues raised are still being encountered, at least in my case. It is also interesting to me that only one case in that study involved a problem with the ground loop, which is essentially the only part of the system with which my problems are asociated.
It does point out that customers often feel caught in the middle of distributors and manufacturers, a situation that I am all too familiar with.
Give Bob Reinmund at Grundfos a call next week. He's a ground water pump guy with lots on the ball & if he can't help, he'll know who you should be talking to. Tell him the guy who wrote "the Grundfos handbook" sent you. He'll be back from vacation next week.
We don't sell the WF brand of GSHP, but their products look good to me. Another local contractor uses their units & he's got nothing but good praise for WF. Although we're compettitors beyond our shop and meeting areas, we're good friends & he's no reason to embellish about their products in our frank discussions.
I'll be at the Solar Decathlon on assignment this weekend, but feel free to contact me via e-mail at [email protected] if you want me to put you in touch with our local WF guru.
This isn't going to help your particular problem but just gives you, and others, an idea of what some problems are like.
I went to a hydronic in-floor heating installation seminar and learned (and forgotten) all about concrete in-floor installations. After the seminar I asked the instructor that now we know how to install the system what was the worst or toughest problem he ever came upon.
He went onto explain that this customer had in floor heating and that it worked just great but then at certain times of the year (I can't remember when) he would get less and less heat and then almost nothing and then a month or so later all would be well again.
To make a long story short, it took years and many man hours from the installation company and manufacture reps to find out what the problem was. And I still think it was luck.
They found that at the certain times of the year the water table came up under the concrete slab and literally sucked the heat right out of the floor and then when the water table went down all worked well.
There is always a reason for everything but can that reason ever be found.
roger