Closed Loop Water System Issues
I live in a condo building, and my HVAC unit is connected to the closed water loop that runs through the coils (for keeping the system cool, I'm told). Over the past 7 years, I have had to replace my Trane unit twice (yes, the entire unit), and I'm pretty certain at this point that it is due to debris in the closed loop water. That being said, the condo board and the building engineer keep saying that the issue is fixed and that they had the towers check/serviced and the water chemicals checked & adjusted (I get that line every year).
I have technicians coming to my apartment regulary to flush out the black water, and then my unit goes back to running normal (less normal each time I have to do this). In fact, some service companies refuse to work in my building because they know what the problem is, and there isn't anything they can do. They also won't give me anything in writing explaining the problem, nor will Trane honor the warranty on their units as a result of this murky water.
Other than a flow regulator that was installed about 9 months after I moved into the unit, everything else about my system is the way it was when the building was built 7 years ago, and I'm told by a couple different service companies that everything is installed properly. So here is where I need some honest advice:
Does the flow/pressure regulator make the water run too slowly, therefor slowing the speed of water in my unit giving the debris/sediment less of a chance to pass through?
Is there some sort of filter I can attach to the closed loop input water line to prevent the gunk from getting in there in the first place?
I seriously am gonna go postal this summer if I can't figure something out (other than moving, which is not an option). Help!
Without seeing your installation, it sounds like each water cooled system (or water source heat pump, which it may be) does not have an in-line strainer installed to catch larger debris. Even if one is installed, it would need regular cleaning to prevent operational problems with the a/c.
Originally Posted by HeywoodJ
Even if the strainer is in place, it cannot prevent scaling and corrosion of the water pipe/heat exchanger surfaces if there's no effective water treatment program in place. Good water treatment makes all the difference how well a closed loop system, chilled water plant, etc. operates. It is perilous for an owner/operator (in your case, the condo association) to not understand and insist on high water treatment quality for his system.
The service companies can't do anything about the closed loop water quality, for it's out of their control (unless they hold the water treatment contract). The only people who can are the ones charged with managing the system. I would bring this before the condo board, if your neighbors or you have not already done so. It's possible the problem involves more than just water quality, and the board knows it and is cringing at what it might cost to remedy. Hard to say from here.
The flow regulator can be a problem is it is adjusted improperly. If it does not let enough water in during high cooling demand, your system may trip out on overload. Also, if the flow regulator does not open up far enough now and then, sediment could build up in the heat exchanger due to solids settling out of the water that is flowing more slowly through the exchanger.
I've seen first hand what neglected closed water loop systems are like and what they can do. It is NOT pretty.
i would recommend getting all of your damages documented
if you keep having to clean scale out of your hx
then imo maybe the building owner should be liable to some extent
or maybe you need to ask permission to install an air cooled system in your condo (good luck with that)
you are in a very tough position, i am sure this is happening with plenty of other tenants
maybe yall need to get together and demand that a proper water maintanance program
be innitiated to avoid further types of similar problems
may be a good idea to move
i would attempt to get information on what type of maintanance is being done with the closed water loop
sometimes when they start treating the water, if the system was full of scale and debris
and the entire system is not flushed properly there can be debris in the loop that may be there for a long
time, but anyway document all your repairs and demand an explanation
fair is fair they should deduct that stuff from your rent
what they should do and what they do are 2 different things
Hey fellas, I appreciate your feedback.
Hey Shophound, your description "trip out on overload" perfectly describes what happens to my system in the summer. The unit gets louder and louder, and then ultimately only the fan comes on (the compressor will come on for a couple seconds, but then cut out).
What would happen if I just removed that regulator? It wasn't there when they built the building, but they put it on later nin response to some of the compaints about how the units were running. If it's pressure related, I never had an issue with leaks or anything like that. Should I pull it off?
Who installed and paid for the regulator? Was it the condo owner or the condo association?
The valve may have been put there in an attempt to balance pressure issues in the closed water loop (just an educated guess). I would not remove it just to "see if that helps". By what you describe, the problem is mainly poor water quality. From what I'm gathering, your condo uses a water loop system which may or may not be open to a cooling tower. If it's open to the cooling tower, it's going to be vulnerable to debris for ever and ever, even with good water treatment. A running cooling tower sucks in all kinds of crap day and night, which must be removed by strainers, filtration, and periodic cleaning. A closed loop system, that uses a heat exchanger between the building loop and the cooling tower water loop, isn't subject to being fouled by matter entering the tower, but if the closed loop is not chemically treated, the water will foul due to eroding pipes and microbials that can grow in the loop.
It's likely you're not the only condo dweller in this building having problems created by the water loop system. I would make it a hot topic at condo board meetings, and find out how the system is being cared for. The performance of that system has a direct affect on the performance and longevity of your own system, as you well know.
Even if you were to jump ahead with removing the regulator, if the water is fouled, it will slow heat transfer. It keeps sounding to me like the water treatment leaves much to be desired.
Call a water treatment company to sample the water. Your going to have to pay but it will verify your fouled up water system.
Not much to say, just hanging in my shade tree!!!!
I know that you wrote you have a closed loop, but just to make sure, inquire if you have a closed loop or open loop. Open loop circulates through a cooling tower. A closed loop rejects heat to the cooling tower through a heat exchanger. If you have a closed loop, red water is a very bad sign, it indicates active corrosion. Black water is good and bad, it indicates lack of O2 (with o2 it would be red), but the black (magnatite sp?) stuff will coat the heat exchange surfaces, esp if the system was not properly flushed of residual oils. The good news is that a closed system can be cleaned up over time through filtration and treatment. The bad news is that it takes board action to correct. A 10% side stream filter can be installed if the closed loop pump has some excess capacity, else a self contained filter and pump set up. With a dirty system, problems are worse at the bottom of a teir. Lightly tinted water with out debris or foul smell is ok.
If you have an open system, you are at the mercy of the maintenance program.
What you can do is learn to back wash your unit. And call a water treatment company to sample and test your water. National companies are NALCO, ARC, Chem-Aqua. Smaller reagional companies are numerous. Look under industrial water treatment. These are commissioned sales guys, they may come and do a field test just to get access to the maintence staff / BOD.
Your water treatment problems
Last edited by DCSCO; 04-04-2008 at 05:37 AM.
Reason: double post
Thank you too for your input, this has all been very helpful.
The building I'm talking about is in Arlington, VA, I just noticed that you're in Frederick. Any chance you work down that way?
Last edited by HeywoodJ; 04-04-2008 at 10:31 PM.
I'm not sure desco's description is right
An open loop system has one pump(possible backup pump too) that pumps water through the system and tower - the tower does not have an exchanger in it at all. thus the water mixes with the air and can pick up all kinds of debris/dust etc.
a closed loop system has the same pump set up that circs water throughout the building and through the tower heat exchanger
the tower then has its own water system seperated from the loop system and has its own pump to pump its water from the bottom of the tower to the top and trickles down - its seperate and does not mix with the loop water
this system tends to sty cleaner and does not pick up as much sediment/debris etc as an open loop system
From what infor is provided - it would seem as if infomation is being held back
its likely that there may be an issue wit the the loop water and expensive issue too.
Water treatment is critical to a loop system
there are filters available - consult your HVAC co for proper application/installation
the op needs to do the following.
1 have a sample of the loop water tested by an independant expert.
2 attend his condo owners meeting and question the council with regards to water treatment of the loop water
3 ask for documentation of the mechanical/loop system.
4 if needed use a lawyer to pressure the council for the paper work regarding the maintenance of the mechanical/loop system.
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Penguin, based on what everyone has been saying, I am pretty sure my system is a closed loop. I think I've heard the engineer make mention of the heat exchanger, and he has told me that back flushing my individual unit is bad for the loop water as a whole (he told me this after I suggested we get a contractor to back flush everyone's unit who had a problem on a regular basis because it would save us all some money if they could do several in one trip).
If you have a closed loop system, and it is properly maintained you should not be having these problems.
Originally Posted by HeywoodJ
With a closed loop system that is being properly maintained back flushing will silute the chemicals in the system. But again if the system has properly chemical levels you should not have to back flush.
You might insist that the maintenance man (does not sound like an engineer) show you the report from the chemical company, and if he does not have any ask why? Normally the chemical company should come around once a month to check the chemical levels and be sure that they are at the correct levels. I have been working stationary since 1971, and I understand the chemistry in treating towers and closed loops. But If our chemical rep was not at the property montly would be repaced. It does not mean that I do not know what I am doing, it is a double check that I and my testing equipment are working properly.
From what you have said there is something wrong with the system and it sounds like your maintenance man does not understand.
Old snipes don't die they just loose their steam
It sounds like your building has serious water flow problems.
One building that I have to deal with is only 2 1/2 years old & the black iron pipe for the closed loop was not flushed out adequately during construction, so the loop had a great deal of oxidation present (not to mention rocks, leaves, etc.).
The oxidation became a black sludge, the consistency of mud (I'm told that, in the presence of air, it would be rust). This and all of the other debris clogged up the strainers. We had 20+ compressor failures out of appox. 135 Water-Source Heat Pump Units in the 1st year!
Even after flushing the loop twice & running a side-stream filter, we are still trying to clean up the loop. It is getting better, but the loop is still contaminated.