Gravity hot water recirculating loops


  #1  
Old 05-22-07, 01:30 PM
W
Member
Thread Starter
Join Date: May 2007
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
Gravity hot water recirculating loops

I have a water heater in basically the center (basement) of my home and wish to run a gravity recirculating loop between three bathrooms, main floor laundry and the kitchen all of which are on the main floor. I understand the theory of how the loop works but I'm wondering if I have to run the whole setup in series, or can I have more than one return loop to the heater, Also I'm wondering if I can use plastic for everything and the last 15-20' 3/4" copper. At a guess the whole loop would be around 100" feet.
 
  #2  
Old 05-22-07, 02:05 PM
C
CSG
CSG is offline
Member
Join Date: May 2007
Location: Naples
Posts: 314
Upvotes: 0
Received 0 Upvotes on 0 Posts
Not sure what you mean by gravity (yes, i know what gravity is ). You need to use a recirc pump or your not circulating. It is also better to run in a series...not individual returns. And as for you return line..only needs to be 1/2". No point in making it 3/4". And you can make the whole thing plastic, even the last 20' if that is what you wish to do. Nothing wrong with CPVC.
 
  #3  
Old 05-22-07, 02:22 PM
Ed Imeduc's Avatar
Member
Join Date: Aug 2002
Location: Mountain Williams Missouri
Posts: 17,505
Upvotes: 0
Received 1 Upvote on 1 Post
Wink

Have ran 3/4" pipe with up hill slope to last tap in. Then just a 3/8" copper pipe Drop down to the floor and run back to the hot water heater. No pump at all. Could use cpvc
 
  #4  
Old 05-22-07, 04:33 PM
W
Member
Join Date: Dec 1999
Location: San Diego Ca. USA
Posts: 984
Upvotes: 0
Received 13 Upvotes on 11 Posts
Hi, You don't use gravity in this system it's convection. To work, the lines have to be above the water heater.Go to the last hot water tap and from that run a small line back to the water heater connect it to the clean out at the bottom of the tank.
Good Luck Woodbutcher
 
  #5  
Old 05-23-07, 06:45 AM
W
Member
Thread Starter
Join Date: May 2007
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
Woodbutcher, yes convection would be the proper term for this, now what I really need to know is, because my hot water runs are to at minimum of four different directions from the water heater (2800sq ft bungalow) from aprox 20' in the shortest direction to about 35' in the longest and opposite direction, should I run all the sources in one loop in "series" or can I make a loop for each of the four main runs and tee them back at bottom of the water heater.

CSG, Woodbutcher knows of the convection system, and how it will circulate without a pump, yes it's a slow circulation, but it's enough to keep the water moving. I do think it would be best to have it in series like you've stated in your pump type systems.

Thanks a bunch guy's
 
  #6  
Old 05-23-07, 09:01 AM
C
CSG
CSG is offline
Member
Join Date: May 2007
Location: Naples
Posts: 314
Upvotes: 0
Received 0 Upvotes on 0 Posts
Yeah, convection didn't even pop in my head. It will work..but your right it is slow. I still believe series is the best option no matter which type of recirc system is used.

I just like pumps..
 
  #7  
Old 05-26-07, 10:01 AM
steve_gro's Avatar
Member
Join Date: Jan 2004
Location: San Francisco
Posts: 967
Upvotes: 0
Received 1 Upvote on 1 Post
There's no reason you couldn't pipe the recirc, try it w/o a pump, then add one later if you need it. Just add valves before & after where the pump would go. I did that in my own house and was surprised that it did work (w/o a pump).

As for multiple vs. single loop, it's a balancing act. I don't know how well it would work with convection, but would guess that one loop would out-perform the others.
 
  #8  
Old 05-28-07, 05:23 AM
cgar's Avatar
Member
Join Date: Nov 2002
Location: MA
Posts: 161
Upvotes: 0
Received 0 Upvotes on 0 Posts
I think a single loop will be the most straight foward and guaranteed to work. It sounds like installation would be more complicated since they are in opposite ends. With individual loop it might be a balancing act between all the returns.

I did this (single loop) years ago and it is fantastic. No power required. One thing that I did do was add a ball valve in the return. This allowed me to throttle the flow so that I got just the right amount of flow. I did it all in 1/2" and you would be surprised how much flow you get. You could also pipe the returns in 1/4", plastic, copper. Just remember to insulate the entire pipe length.

Something you may want to try is consolidating as many of the loops so that you minimize your # of loops. Add valves so that you could balance if needed. Please post back if you run multiple loops. I am curious as to how well it would work.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: