Water Htr Heats Dom HW and Hydronic System in same pipe

RayWohlfarth

I was looking at a system in a college in my area and the client is using a Raypak copper water heater to heat both the domestic hot water and hydronic system using the same pipes. The water will either go to the domestic water or to water source heat pumps on the hydronic. system. The boiler/water heater is set at 120 degrees.

I cannot believe that this is proper but I cannot find anything in either the International Mechanical Code or the International Plumbing code that says that it cannot be done. Does anyone know of a code that shows that they cannot use the same pipe and boiler for both? I had always used an indirect coil or heat exchanger when doing this in the past.

Thanks

Ray

Henry

Certification

It is simple, the boiler is either certified as a heating boiler or DHW boiler. It is in its listing. The certified I&O manual specifies how it is to be plumbed. If it is not followed, it is in violation.

Mark Eatherton

Subject to interpretation...

Hi Ray,



Dave Yates and myself attempted to influence legislation on this very subject a few years back. We came away with nothing but bloody knuckles, and a bad taste in our mouths as it pertains to the way things are done in the code approval process.



At present, under the I and U codes, so long as the appliance is "approved" as a space heating and DHW heating appliance, then it is good to go. We lost to the power of the almighty buck (read water heater manufacturers who hire professional lobbyist to influence the outcomes to their advantage) and the Home Builders Association, a known lobbying group.



We plead with them to consider the health impact of their decision (thinking Legionella and Pontiac fever production as well as many other water borne diseases) to no avail. The CDC has said numerous times, that Legionella is THE most misdiagnosed disease in the WORLD, yet this committee asked us to "show us the bodies", and refused to recognize the CDA's reports.



However, the local AHJ can outlaw the use of combination systems, because by law they can be "equal to or more stringent than" the national standard. Numerous of our local county AHJ's have outlawed the use of combination, single fluid, potable water/space heating systems. Within the code, as it pertains to potable water handling, nothing that could possibly cause the water to become a "questionable character" is allowed, and in my and the opinions of other master plumbers, charged with protecting the health of the nation, these combination, single fluid systems WILL and DO change the characteristics of the water by giving ideal conditions under which the bacteria can not only live, but can also thrive and multiply.



Fixing an existing situation is going to be expensive, because you will have to install a new and separate space heating distribution system in order to isolate the two fluids. That, or leave the existing system as is, and install a new potable hot water distribution system, neither of which is inexpensive.



If it were me, I'd split the systems and maintain the DHW system at a minimum of 130 degrees F, with anti scald valves at the points of use. I'd also take the Chief Building Official of your jurisdiction out for lunch, and explain the dangerous situation to him so he can adopt some changes to the existing code.



BTW, I am reading your book on commercial boiler systems, and find it an excellent read. Now, if I can just find time to finish reading it, life will be good. ;-)



Thanks for writing.



ME

RayWohlfarth

Thanks

Henry, Thanks. It appears that the existing boiler is certified for both.

Mark, Thanks for the input. It amazes me. When I spoke with the owner about using that nasty water to take a shower in, he simply shrugged and said Its fine after they let it run for a little bit.

Mark, Thanks for the reading the book and the comments. I consider it high praise coming from you. I enjoy your writing as well.

Ray

Mark Eatherton

Possible solution...

Ray, if there is a wet fire protection system in place, you might be able to convert the space heating system to utilize the fire protection system to serve as the heating system distribution system. This is allowed under the fire code. The flow switch obviously can't be a part of the distribution/circulation loop...



Thanks for the kudos.



ME

RayWohlfarth

Great idea

Mark, that's a great idea. I didn't think of that option. The client is content not spending any money because he says it meets the code. I have no ammunition to make him change. I appreciate the expertise

Ray

Mark Eatherton

Ask him if....

there have ever been a lot of cases of bacterial pneumonia in his school. THAT is Legionaires disease in disguise.



I know this because I've had it (Leginoaires Disease) before, and I can tell you that it is not anything I'd wish upon my worst enemies. I was one day away from total and complete collapse.



The only good thing about having contracted this deadly disease, is that there are NO confirmed cases of anyone having ever caught it a second time.



Google Dave Yates and Legionella and print those articles and give them to the consumer and see what his response is. I've written a few as well, but Dave is my go to man when it comes to this disease. He opened my eyes towards its potential.



Most commonly misdiagnosed disease in the W O R L D ....



ME

Dave_132

Dave

Combined appliance applications are nothing new. Half of all Denver condominium & apartment complexes built in the last 20 years employ this type of system. And if the contaminated water was not enough, the fan coils have been known to burst due to elevated city water pressure and freezing due to direct expansion a/c coils in close proximity. I now refer to these systems as the California package. The life of the water heaters are drastically reduced due to the double duty. I have also noticed that the tenants and homeowners raise the temperature setting to the max during extreme cold conditions.

Dave_132

Dave

RayWohlfarth

Wow

Mark Thanks I will do so I am familiar with Dave Yates I think he is from the other side of my state

Steamhead

Dave is located here:

http://www.heatinghelp.com/professional/75/F-W-Behler-Inc

Henry

140F!!!

Legionella survives up to 139F. A few years back, our National Code was going to mandate 120F and then 130F for hot water tanks untill someone realised that we needed at least 140F in the storage tank to kill the bacteria. Now the standard is 140F in the tank and 120F at the faucet.

From what I can gather, only combo tanks are aprooved for DHW and heating. I know of no boiler that is aprooved for DHW and heating using the same heat exchanger. Some boilers have glass lined headders that allow them to be used for DHW after changing the safety valve but not for both DHW and heating.

Mark Eatherton

Up hill battle...

Henry, On this side of the border, we have all of our utilities doing paid advertisements telling people to TURN IT DOWN... They are backed by a large group of lawyers, who have profited from lawsuits pertaining to hot water scalding cases.



We can't ignore that potential, and maintaining a tank at 140 degrees F without a means of anti-scald at the P.O.U. is asking for trouble. In new construction, whereby all required anti-scald devices are in place at the P.O.U.'s, it is not a problem. It's the older homes/buildings that use conventional mixing technologies that it becomes a problem. Soft tissue damage from excessively hot water (scalding) is VERY painful.



Raypak use to promote their combination, single fluid space heat and DHW systems, but I've not seen anything on them in quite a while. Maybe one of their reps will step in and let us know which package still carries the NSF approval for this type of system.



Maybe it didn't withstand the test of time...



As it pertains to scald potentials, I'd rather see all of the money that is being spent on telling people to turn their water temperatures down directed towards education regarding higher water temperatures, and the possibility of exposure to Legionella Pneumophila when using lower water temperatures.



One of these days...



ME

Zman

Interesting article

I found this article this morning http://www.legionellaprevention.org/default.html

I wonder how many cases of pneumonia contracted in hospitals and nursing homes are legionilla? They certainly have zero motive to test for it. A friend of mine is a mechanical engineer for new hospitals. They us chlorine recirc systems on all "dead legs". I do not believe older facilities and nursing homes do.

Just ordered you book Ray, Can't wait!

Carl

RayWohlfarth

Thanks

Carl

Thanks for ordering the book. Please let me know what you think

Ray

RayWohlfarth

Legionella

Mark,

That Legionella is some nasty stuff. I am familiar with what it can do and want nothing to do with it. There is a lady that worked for the VA hospital in Pittsburgh that was an expert on it. I heard her speak about it and it scared the tar out of me.

ray

Mark Eatherton

My good friend Robert Bean...

Honestly, I do not know when this guy sleeps...



http://www.healthyheating.com/water-heater-efficiency.htm



This is an excellent resource for anyone in the human comfort/efficiency business.





ME