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[Wood Nutt]

I have a ball valve on my DHW side that has one inlet and two outlets and flow cannot be shut off, only diverted one way or the other (not both).  That might be an option for diverting the flow, you would essentially have 4 loops but only be able to flow thru only two of them, i.e.  between Loop 1A or 1B and Loop 2A or 2B

[Midnight Farms]

Thanks Wood Nutt...  that helps.  I guess my question about that ball valve specifically is do you lose much (if any) flow from it?

This option with basically 4 loops is great, however, that is a lot of extra insulated pipe.  And at $5 to $10 a foot for it, and lengths of 150 feet to the house, it starts to add up.  If I could do it with a large line to the Manifold at the house, I am assuming it would be cheaper, and potentially a more controllable option.
Any other thoughts about Manifolds at the house?  Anyone have pictures or other links for these?

Thanks!

[Wood Nutt]

I don't know were all 4 of the heating places are in relation to each another, but you can basically put the pumps wherever you have electricity and protection from freezing when not in use (back of OWB, house, etc).  Hopefully, that would minimize the amount of insulated pipe you would need.  You should also be able to get a single insulated set with 4 each 1-inch lines in it if that works better and at a lower unit price than 2 sets with only 2 each 1-inch lines in them.

Here is a link to one of the valves

http://www.zoro.com/g/3-Way%20Bronze%20Ball%20Diverter%20Valves/00060026/None

and it comes in both 1 and 1-1/4".  I actually have the 3/4" valve but it is on my DHW side and I bypass my plate exchanger with it in the summer when the OWB is not in operation.

[Midnight Farms]

I have continued to look into the Manifold idea.  Unfortunately, I can't find any that are rated for more than 2.3 gpm out of each line.  The Manifold itself is rated for a total of 15 to 18gpm.  I am assuming, 2.3gpm to a furnace probably isn't enough.  Thoughts?


Second question: The dual loop idea.  Is there calculators I can use to determine if my pipe diameter, distance from burner, and devices will pull too much temperature, thus sending the water back to the OWB to cool?  The information is 150ft x 1 1/4inch from burner to house, 50ft x 1 1/4inch from wall to furnace (160K BTU Water/Air Exchanger), 10 ft x 1 from furnace to water heater (Brazed Plate Exchanger 5 inch x 12 inch x 20 plate, 97K BTU), 50 ft to wall, then 150ft back to burner.

Lastly- Is there any issue/advantage/disadvantage of going from a 1 1/4 supply and return line, down to the 1 inch for the heat exchange devices? Or is it best to utilize a 1 inch supply and return line to match the equipment?

Thanks!
~Nick

[LittleJohn]

I have continued to look into the Manifold idea.  Unfortunately, I can't find any that are rated for more than 2.3 gpm out of each line.  The Manifold itself is rated for a total of 15 to 18gpm.  I am assuming, 2.3gpm to a furnace probably isn't enough.  Thoughts?

With this manifold/header (whatever you want to call it) flow for each loop would be about 5.5 GPM (3/4" Copper at 4ft/s) and the whole manifold at about 15.3 GPM (1-1/4" Copper at 4ft/s):  http://www.pexuniverse.com/sioux-chief-12-port-copper-manifold-6795l-12333

There should be no perfomance issue necking down 1-1/4" to 1" for heat exchanger, other than more water in system and that your system will see less head pressure with the larger 1-1/4" feed lines versuses 1" lines, at a same GPM.  One down side is 1-1/4" is $$$ more than 1" 

[willieG]

buy one of those for 85 bucks, cut it in half and you have about the cheapest manifold you will find and likely more ports than you could deliver water too (unless you were cutting them down to 1/2 inch)

1.25 pex at 4 feet per second is 11.2 gpm
if after the header you were using 3/4 copper it is rated at 6.5 gpm at 4 feet per second

so, 2 copper runs off the main header could draw all the water (more actually) then the 1.25 pex could deliver. However if the delivery water was 180 degrees and figuring your delta of 20 degrees you could expect  to have 110,000 btu per hour to divide amongst any outlets you add to the main header.

[LittleJohn]

Willie, you can run PEX faster than 4ft/s; 1-1/4" PEX at 8ft/s if like 21GPM or something.   Velocities over 8ft/s IN ANY HYDRONIC SYSTEM can be an issue of noise and/or turbulence.
NOW THAT BEING SAID, the velocity (over 4ft/s) is only an issue with METALLIC parts.  Because as you exceed a water temperature of 140f, erosion of metal can occur if the velocity is over 4ft/s and you can develop pin hole leak eventually (typically after a sharp bend in the pipe).

I personnally do not run water than fast in any of my systems, but I also have a lot of inslab, which does not require a high flow rate

[willieG]

I understand you can pump more water than the number I used but I think(if I was figuring right) 20 gpm through 200 feet of 1 1/4 pex would be a head pressure of about 30 feet, that would take a large pump and lots of electricity. (here in Ontario where we have ((I think) the most expensive electricity in the world)  that would cost a lot to operate so  I used a number that would put you at about 12 feet of head in that length of pipe

I think 20 gpm was 30 feet of head
16 gpm was 19 feet of head and
12 gpm was 12 feet of head

I think a grundfos 26-99 would do the  12 or 16 gpm

I never looked to see what type of pump you may need for the 20 gpm

here in my part of Ontario Canada we are up to right now (and another price hike coming soon) about 22 to 25 cents per KWH

for me to run this pump 24/7 would cost me about 1.20 per day

I think power in the states is likely about a quarter the cost?

[LittleJohn]

Willie I agree, just BECAUSE YOU CAN DOES NOT MEAN YOU SHOULD, run that fast (8ft/s), that is why I added the note about erosion of metal parts in hydronic system when velocities get above 4ft/s and the issues of turbulance and noise.

BTW, I also like smaller pumps  , electicity isn't as bad as Canada's, YET