I had a lot of time on the airplane to and from Chicago the last two days, so tried to lay out my water supply plans. I am planning on using PEX and running a home run system with a few of the lines having T branches. Does what I have planned make sense for a house where my bathrooms are stacked and the HW is in the basement just below the kitchen and next to the bathrooms:
COLD
Line 1- to T connection for DW and Kitchen sink -3/8"
Line 2- to front hose bib- 3/8"
Line 3- to T connection-to WC upstairs and WC below, then off the lower line, another T for hose bibs at rear of house- 3/8"
Line 4- to main bathroom lav- 3/8"
Line 5- to main bathroom tub- 1/2"
Line 6- to basement bathroom lav- 3/8"
Line 7- to basement bathroom tub- 1/2"
Line 8- to T connection to washer and utility sink-3/8"
HOT
Line 1- to kitchen sink- 3/8"
Line 2- to main bathroom lav-3/8"
Line 3- to main bathroom tub- 1/2"
Line 4- to basement bathroom lav- 3/8"
Line 5- to basement bathroom tub- 1/2"
Line 6- to T connection to washer and utility sink- 3/8"
By my rough estimates, I will need less than 250 feet of 3/8" tubing and less than 100 feet of 1/2" (actually my calcs are 219' and 65' respectively)
Any insights would be appreciated.
Thanks,
mt
IIRC, 3/8" PEX flows up to 2.5 GPM; but I don't recall at what pressure. That restricts its use to one fixture per run. Just a FYI note, 3/8 and 1/2 PEX have smaller ID than copper, especially at the fittings. The PEX is say 3/8" ID but when you stick a fitting in there the hole is much smaller.
I would not like 3/8" for a hose bib, myself, for sure.
The flow is partly dependent on the pressure of course. When we re-piped the entire house we used 3/4" for major lines; incoming water to WH, hose bibs and distribution manifolds. from there everything was 1/2". We run 35 PSI and even on the non compliant utility sink the flow is slower than I'd like at times.
I had considered 3/8" for the cabin because it is smaller and because I wanted to have as little water in the lines as possible. After the re-pipe on the house I decided on all 1/2" for inside the cabin because of flow. I look forward to hearing what others think on the pipe sizing.
If you are using a conventional HW storage tank with the tank you might think about installing a hot water recirculation pump. It makes hot water available right now. There are 2 basic varieties, one with a timer actuated pump, you set the intervals to coincide with your life pattern. The other has a push button switch at the sink station and you activate as needed. We went the timed route as it was easier to retrofit. It makes quite a difference at the bath sinks and showers. Not neeeded for things like clothes washing.
Thanks, Don. My pressure is really strong--I want to say 11 gpm. I think I need a pressure reducer, in fact.
I got my pipe sizing from an online PEX guide, but I do want feedback like you gave me before I do anything.
I will look into the recirc pump. My distances are not very far, but still....
With appreciation,
mt
Also, on the HW recirculating thing... If the WH is in the basement below the fixtures you can plumb a third line to act as a return line for a thermosiphon loop. No pump needed. The return gets plumbed from the uppermost fixture down to the bottom of the tank. You remove the drain, install some fittings and a tee. Especially with this you should insulate the lines so you are not causing excessive heat loss from the warm pipes.
In humid climates it can also be a good idea to insulate all the cold lines to avoid condensation within enclosed spaces.
We installed a pressure reducer with the repipe. The city delivered water had a pressure that varied from 90 to 120 pounds. At times it peaked higher according to a plumber. He told me his 140# gauge was broken by pressure on one job.
If your pressure is significantly higher than 50 pounds I'd get a reducer. They are very cheap these days. The lower pressure is better for things like the auto valve on DW and clothes washers. It does slow down on the flow though.
I'd skip the 3/8 and do the whole house in 1/2. Less wasted pipe and better flow less confusion. Some of your runs are undersized IMO. And as Don mentioned a hose bib needs a good flow. I never use 3/8. The mains feeding your manifolds and W/H need to be 3/4". My rule of thumb is no more than 2 fixtures on a 1/2" line.
Thanks, guys:
3/4 to WH and manifold
1/2 everywhere esle
COLD
Line 1- to T connection for DW and Kitchen sink
Line 2- to front hose bib
Line 3- to T connection-to WC upstairs and WC below,
Line 4- to main bathroom lav
Line 5- to main bathroom tub
Line 6- to basement bathroom lav
Line 7- to basement bathroom tub
Line 8- to T connection to washer and utility sink
Line 9- T to rear hose bibs, one on each level
HOT
Line 1- to kitchen sink
Line 2- to main bathroom lav
Line 3- to main bathroom tub
Line 4- to basement bathroom lav
Line 5- to basement bathroom tub
Line 6- to T connection to washer and utility sink
Do you think it is a decent idea to run a hot water line to a hose bib off my front porch? I was thinking that this might be a good way for the kids to get the sand off them when they return from the beach and since my utility sink is in the basement, I would have a long run if I needed hot water in a hose....
Hmmm. How about installing an RV outdoor shower set...
(http://www.pplmotorhomes.com/parts/rv-pumps-water/exterior-rv-shower.jpg)
http://www.pplmotorhomes.com/parts/rv-pumps-water/exterior-rv-shower.htm (http://www.pplmotorhomes.com/parts/rv-pumps-water/exterior-rv-shower.htm)
Don,
Can you dig up a picture of the thermosiphon set up you are talking about on the HW heater. I might also do this on my portland house when I am done with the beach project.
mt
Mike, I don't have a picture at hand, but here is a bookmark I had on an article...
http://www.askthebuilder.com/147_Gravity_Hot_Water_Recirculating_Loops.shtml (http://www.askthebuilder.com/147_Gravity_Hot_Water_Recirculating_Loops.shtml)
I want to add that the main reason we installed a recirculation pump system with the re-pipe was that our master bath is at the north side of the house and the water heater is located close to the south side of the house. The second bathroom was only 8-10 feet closer to the tank. We wasted gallons of water every time we wanted hot water at the sink, tub or shower. Being in the desert our water concerns are greater than those of some others. We do waste some energy due to heat losses in the pipe if we are not using the warm water that waiting. Our system has a sensor that stops the flow of water in the loop when the water temp at the loop end, under the furthest sink, reaches something like 80 degrees.
In the thermosiphon system you must insulate the pipes well as that system will place hot water in the loops 24/7. I would install a shutoff at both ends of the return loop just in case you want to deactivate the recirculation for any reason. We did that on our pump loop as well.
Thanks, Don. I kind of thought that it might not cost out, but I wanted to check. Where I am building there is a minimum charge for water use, with not living there full time, it is hard to imagine ever going beyond the minimum. That said, I hate wasting energy or resources in whatever form, so if I can be forward thinking and resource prudent, I will look into it.