What size do risers need to be?
What is the required size for risers to meet code? I’m being told that a two family (lower duplex and upper triplex) needs one inch copper risers for both cold water and hot water. Then half inch would branch off to each fixture. Will an inspector ok 3/4 inch? One inch seems excessive to me….
What is the required size for risers to meet code? I’m being told that a two family (lower duplex and upper triplex) needs one inch copper risers for both cold water and hot water. Then half inch would branch off to each fixture. Will an inspector ok 3/4 inch? One inch seems excessive to me. Does anyone have the link to where this code would be?
I am so glad that I found this post. I have the same problem and was questioning what size of pipe to use as well. I can work with hot water heaters till the cows come home, but when it comes to cars and injection pumps, I am a brick.
I thought the green jobs were going to go to unemployed analysts and I-bankers.
eman1234 I posted about your comment here:
http://ecobrooklyn.com/try-something-new-despite-what-they-say/
Thanks for the comment! It made me think.
oh christ its the former wedding officiator from ibiza that is attempting to redefine himself as a green contractor…look at the eco brooklyn blog..the guy does not have a clue about anything..everything is done 2 or 3 times because he keeps trying to reinvent the wheel instead of biting the bullet and paying a professional to do the work the right way..
gennaro, good ideas. But I think if previous posters are right, you don’t have a say in reducing the riser below code.
The second pump can be retrofitted *w/o* a h/w return because can dump water into the cold pipe until hot reaches the pump (www.chilipepperapp.com/ and metlund.com). It’s a little noisy and of course, you still have to wait 10-20 secs but you’re not wasting hot water.
Forgot the link to the diagram
http://ecobrooklyn.com/hot-water-home-run-return-mixing/
That is a good link at Engineeringtoolbox.
I’ve thought a lot about hot water returns.
Here are my conclusions in short.
You want a small hot water return pipe to reduce the heat loss. 1/2 is ok. You put a variable rate pump with a temperature gauge on it.
Once the return temperature reaches a certain hot temperature level the pump slows down to a trickle to offset the heat loss through the pipes. If you are insulated that loss in minimal and the trickle can be miniscule.
This way you aren’t wasting electricity on the pump.
You also want a timer on the pump so that it is is completely turned off during off peak hours. For example at night and in accordance with your daytime usage.
You want to insulate the pipes like you are obsessed. Just go crazy with the insulation.
If you really want to make it as efficient as possible then instead of the constantly on pump with variable rate gauge on it you have the pump default be off.
Then you put a button near the hot water faucets. When you want hot water you press the button, which turns the pump on, and then you wait a few seconds before opening the hot water faucet. With a normal faucet you would wait as well, the difference is that in this case the water is flowing down the hot water return pipe back to the boiler instead of flowing down the sink.
This second way isn’t about having instant hot water. It is about saving water. You are taking a luxury feature and turning it into a green feature. As a green contractor that is more important to me. You aren’t really inconvenienced since you have to wait anyway.
(You don’t want to have a motion control sensor turn on the pump because a lot of times you enter the bathroom but don’t use the hot water. This could create too many false alarms [70% from one study I read]).
The first option with pump constantly on but low is a mix of the two best options: You have the luxury of instant hot water and you aren’t wasting that much energy. The little energy you do waste is offset by the water you save. I’ve not done the numbers but that is the logic at least.
Here is a diagram of what a hot water return looks like. I think it is a good feature and worth the investment since it reduces on water bills plus gives you instant hot water. Green and more comfortable! That’s the spirit!
Do you mean a recirculation line? Isn’t that a good way to waste energy? Why not a on-demand recirculator?
“pipe sizing shall be predicated on hydraulic design by an architect or engineer, subject to approval by commissioner”(16P107.5)… it is not your job to dictate riser size, and you would be a fool to undersize risers…also plan for a hot water return line if your run is over 60 feet