Letters To The Editor - March 2009
March 1, 2009
Looking for a Manufacturer's MarkI very much enjoy your pme magazine and MyPlumbingPortal.com. Hope you can help me answer a question. I have a kitchen faucet that I bought four to five years ago for $150-$200. Unfortunately, it now leaks and I want to contact the manufacturer, but I don’t see any manufacturer’s marks on it. How can I find out the manufacturer of the faucet?
posted by a visitor of MyPlumbingPortal.com
Julius Ballanco responds:
The ANSI/ASME A112.18.1 standard requires the faucet to be marked in a visible location, after installation, with the manufacturer’s name, trademark, or other name that identifies the manufacturer. If no marking is visible, it is possible that there is no marking anywhere on the faucet. Without a visible marking, the faucet would not be in compliance with the standard. Hence, it may not be a code-complying faucet.
By the way, this standard is for all faucets and is mandated by all of the plumbing codes in the country. The standard dates back more than 30 years in the Plumbing Codes and is updated every five years.
Hydronic Baseboard SizingEvery time I do a hydronic baseboard system, I end up with the same question: How do I size the gpm in the baseboard? I hope John Siegenthaler can help. We have one chart that says 3 or 4 fps in the radiant tubing, and that is straightforward. We also have the rating for the baseboard at the average hydronic fluid temperature, usually 170°F (160º-180ºF). But the kicker is that when we go to our load calc using that baseboard, we almost always come up with a flow rate far less than that required for the velocity requirements (3-4 fps).
Usually these numbers are so small that balancers can’t achieve them, so we typically put in the velocity number and calculate the Delta temperature.
Now with a system like this, I would think that we’d be cycling the control valve more often and that our circulating pump will be oversized if we base it on the velocity flow rates. If you have a historical article on this issue I’d like to see it and try and solve this issue once and for all.
Jerry Hendrickson, P.E.
Senior Mechanical Engineer
John Siegenthaler responds:
We have developed some detailed performance models for fin-tube baseboard, and put them into software called the Hydronics Design Studio. The models adjust the output of a specific manufacturer’s baseboard for flow, water temperature, and surrounding air temperature. You can download a demo of the Hydronics Design Studio software at www.hydronicpros,com.
There is no one “correct” flow rate at which the baseboard needs to operate. Ratings are typically listed for 1 and 4 gpm, but these are somewhat arbitrary values. Thermal output increases marginally with increasing flow rate, but the relationship is very non-linear. Higher flow rates tend to give very marginal increases in heat transfer, but not significantly compared to pumping power requirements. I’ve also written about these engineering models in pme. See the June 2002 issue.
A "Greener"Frequently, I re-read articles by John Siegenthaler, P.E. Such is the case regarding A “Greener” Hydronic System from an older issue of pme [Oct. 2007]. I am in the midst of a home renovation project and have been doing extensive research on the type of heating system that I want to install. I had a concept in my mind but I was not quite sure how to optimize it. When I read John’s article, it brought together so many of the ideas that I had and really helped me think through the design.
I am an engineer and have spent the last few years focusing on the energy-efficient design of residential HVAC systems. Although I know there’s a ton of room for improvement in residential distribution system performance, the focus of my work has been on the air side and I have very little design experience with hydronics. I am well aware of the efficiency losses associated with ducted distribution systems, so I knew that I wanted to stick with hydronics for my own house. Plus, I live in the Northeast and it’s the standard.
The only thing his article did not address was unoccupied setback. Perhaps my thinking is skewed by air systems, but it seems the system he outlined could still benefit from a programmable thermostat.
It is a pleasure to find articles written for engineers that use technical content to challenge the standard thinking. I think that reiterating how the basic principles work and how they can work better is a terrific way to challenge designers to rethink their approach.
CTG Energetics, Inc.