Combination Domestic & Space Heat from HWT

Brad_11

I hope I can get some input from you folks. Up here in Vermont, we're on the verge of adopting the IPC 2003. Our Plumbers Examining Board (PEB) has amended Section 501.2 to require the separation of space heating water from domestic use water. Opponents of the amendment want the code to be adopted as is, thus allowing the mixing of potable supply and space heating water. Opponents argue that such systems have a greater efficiency. Are these systems common in other states? How do other localities test the potability of the water in such systems? Are there studies that provide data related to systems that use a hot water tank to supply both domestic and space heating water without separation? Thanks.

Paul Pollets

Separate Systems

Daye Yates is the resident expert on closed loop vs open loop systems. Closed loop systems are preferred for many reasons, possible contamination of the potable supply and legionella are but a few. Using water heaters in Vermont for heating would not be very efficient also due to large heatloss up the chimney. A condensing boiler would be preferred on a radiant load. There is ample data (and a few lawsuits related to improper piping practices) to support the arguments. Post a message to Dave Yates on the Wall, and you'll hear from him.


To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Dave Yates (PAH)

Where to begin...........................

First of all, there's nothing that enhances efficiencies by utilizing an open system with the exception that an additional pump is required for closed systems - using about the same amount of electricity as a refrigerator light bulb. When you stop to consider the benefits that wee bit of energy grants, it's well worth the investment in health benefits gained.

If free air conditioning is part of the stated "benefits" the open system side is claiming, I have the cold hard facts stored in my laptop and home computer, which I'll gladly share with you if needed. Just as there's "no free lunch", the over-extended hype regarding free air conditioning by diverting incoming potable water through floor circuits doesn't hold up when crunching the real numbers. A side "benefit" of diverting cold potable water through floor circuits residing in an insulated joist bay is the condensation and mold growth potential. I have the dew points nailed down too. And, if you've been told watering the lawn somehow grants extra free A/C, I can debunk that myth too.

Legoionella bacteria is present in our potable water systems. That's a well established fact and there have been a number of studies that clearly link residential potable hot water systems as being excellent breeding environments. A few deaths have been traced to home potable hot water systems & although that's difficult to do within the time frame required to absolutely identify that as the source, it's not impossible because Legionella bacteria have a wide variety of strains, which can be traced much like fingerprints or DNA. That's also why the legal community is finding Legionella cases to hold great monetary potential. It's traceable.

There's an article in the Nov/Dec issue of Smart Homeowner Magazine that details open and closed system construction and the potential risks/benefits. I worked hard at trying to present the information to consumers on a level they could easily understand & without the technical jargon we typically use/understand as contractors.

There's an excellent DVD available for free from Watts (www.wattsreg.com) called "Danger - Scalding Lurks". Although it does not deal directly with open systems, it does explain quite clearly that our potable hot water systems and codes need to be revised if we are to protect the American consumer.

If you'd like to read a bit of give and take on open vs. closed systems, you can read the commentary at the RPA site:
http://www.rpa-info.com/forums/forumdisplay.cgi?action=topics&number=A:000002&SUBMIT=Go

Other articles you may find interesting and helpful:

http://www.contractormag.com/articles/column.cfm?columnid=98

http://www.contractormag.com/articles/column.cfm?columnid=17

http://www.contractormag.com/articles/column.cfm?columnid=162

http://www.contractormag.com/articles/column.cfm?columnid=168

http://www.contractormag.com/articles/column.cfm?columnid=193

If you're still awake(G), try putting "Legionella + potable hot water" into Google or your favorite search engine. In all of the research I've done over several years time, I have yet to find any scientific evidence that supports the notion that open systems can be safe. In fact, they can't help but be a perfectly suitable bacteria breeding environment and, therefore, offer great potential for degrading potable water. In my opinion, it makes no sense to condone or permit the inclusion of a non-necessary component within our potable water systems - especially one which offers the potential of bringing death.

Nothing more than a suitable dose of common sense is needed to arrive at the only conclusion the scientific evidence indicates - hydronic and potable water must be separated.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Brad_11

Thanks to Dave Yates

Your help is appreciated. I will check out all the various links you have provided. I'm still hoping that there are others in the trade community that will share their knowledge concerning this topic. Thanks again.

hr

Be hard to add

much to what Dave posted.

We have pushed the proponents of open systems to provide hard enginnered data on that efficiency claim they cling on to! Follow the threads at the RPA site to see where we ended up.

Given they can't, or won't, provide any hard data, AND the health issues surrounding the combined systems... the answer to anybody charged with "protecting the health of the nation" should be crystal clear

hot rod

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Dave Yates (PAH)

Sadly

the only response the open system supporters ever had was "Show me the bodies". Since there were no deaths directly connected to an open system, the thinking was (I'm guessing) that open systems must therefore be safe - right?

But, as you'll find if you visit Janet Stoudt's web site and download "Legionella - The Coming of the Third Plague", our potable hot water systems have already been tested and varying percentages found to contain measurable levels of Legionella Sero Group #1 - the bad boys of Legionella strains. When you look at the dates of the five surveys, it's interesting to note they fall within a time frame in which water heaters were pre-set for 140F. Given that the factory settings were lowered to approximately 120F since those tests were performed, I can't help but think we'd see an increase in the number housing this bacteria.

Given that several deaths have been clearly identified as having come from residential potable hot water systems, there is conclusive evidence problems already exist that can be life threatening. Given that the bacteria's needs for reproduction are most favorable in identical conditions an open system would offer, there can be no doubt about the eventuallity of bodies. I see no need to wait until open systems kill. Community acquired LD deaths (CAP) are simply listed as death from pneumonia and seldom cultured to determine which type of pneumonia. The CDC estimates CAP at 10,000 deaths per year (approximate - could be higher or lower). Personally, I find the "show me the bodies" statement to be an offensive disregard for the building body of evidence that establishes a clear link between potable water and Legionella. An even more aggregious claim is that those of us who are advocating closed systems are trying to make hydronic systems unaffordable for the average Jane or Joe Homeowner and overcomplicate the systems so that they’re beyond the capabilities of weekend warriors. Nothing could be farther from the truth as our efforts are directed at protecting the consumer’s health.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

hr

Think I would leave

the "body count" issure out of the presentation

Every plumbing code I have tested and worked under makes it real clear the plumber is responsible for maintaining the safety of the systems, potable and heating.

Cross connections are addressed in all codes also. In my mind this is the strongest issue with AHJ's responsability in protecting against any potential issues with potable/ heating systems shared connections.

Most code officials and AHJ understand this concept.

Maybe enlist the help of Julius Ballanco also. He is a well know and respected in the code writting and enforcment issues as well 219-922-6171. The more pros, and data, in your corner the better.

hot rod

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Firedragon_4

I've never liked that idea, never will!

I side with Dave (as usual) and the MA Plumbing Board has approved a few, as test cases, but in the end I think the current approvals will be revoked, JME&IO!

Dave Yates (PAH)

agreed

Chust wanted to get any potential bumps in the road out and in the clear so he's not blindsided.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Weezbo

thats too bad.

luckily the voice of reason nearly 400 years ago or better decieded that sanitary potable water was the way to cruise, good thing that you have hospitals in your state,perhaps you could find someone who works administrating one of them to clarify why they use auto claves and the like on surgical instruments...you know ...just to help keep the board on the same Page as it were.................not sayin the board is made of anyone who has ever done any plumbing mind you however if they have.....perhaps you could get one of them to explain sanitary cross connections and then you might ask him well why the **** do you think we do that ?in as polite a way as possible.....if his answer is "Because its Code!" then i dont know that any amount of work will produce a single thought. simply adopting codes because its the easiest way to manage the system is a sad commentary on the ails of this country today,God gave us a brain,its a good thing it doesnt seem to wear out from using it.Be sane and dont put any system in a human beings home that could potentialy poison them .if the board decieded to pump sanitary sewage or grey water into the water in a home dont be out there doing it....leave them to natural selection...if listening isnt one of thier strong points then talking with them is a one way street.pass out ear plugs first, possibly some of what you are saying will go in and not leak out the other side right away.one each it is common sence seperate the water with a heat exchanger...maybe a double wall heat exchanger would even be better. *~/:) one of the human beings.

Jack_21

I can't imagine a good reason to

want an open loop system. False economy, IMHO, given the risks. The other side to this is the system efficiency. In 1992 the laws went into effect requiring that heating appliances be required to meet a minimum of 78% afue. Most boilers made it easily without to much modification but it required the complete redesign of all gas nat'l draft gas furnaces. Water heaters were so inefficient that they were granted special exemption with their .60EF. To my mind, using the inefficient water heater to heat space simply allows people to skirt the standards, as well as the codes. "Oh,(wink, wink) that isn't a boiler, it is a water heater (wink, wink)". Perhaps I'm just afraid of the Trial Lawyers Assoc.