600' of 1"??????
Is that your loop from the Garn to the house?
Here's the set up. I have four zones (three heating units and one DHW - two tanks). I'm running each specific zone as it's own loop (supply and return) to the Garn barn. So that means 8 individual runs of pex. Heaterman, I know you are a pro, I'm over explaining in case someone reads this later. Each zone pump is at the manifold, and the manifold will be in the Garn barn. Maybe this isn't typical, so let me explain why we chose to do it that way.
First up, the house is 8500 sq feet and is built "long" because it overlooks a river in back. We had to build the Garn barn on the east side of the house so that it wouldn't block the view.
I'm about 16 ft off the east side of the house with the Garn barn. Each loop (supply and return) from the Garn barn, goes to the house and enters through a crawl space. Most of the house is over a basement, but there is a section of the house that has a crawl space. Here's where it gets expensive. Once I run the initial 16 feet underground and come into the crawl space, each loops goes in a totally different direction. One heating loop heads 25' south into the garage for an upstairs bonus room heating unit, one loop heads 35' north and down for a basement heating unit, and two loops head a ridiculous amount west for a DHW and a heating unit.
So why not just run a primary loop from the Garn barn to the house and set up a manifold with the pumps in the house. Because ultimately, the next best place to put the manifold was in the garage, and it didn't save me any distance when I've still got a pex run from a pump to each zone. Basically, the garage is the same distance from the other zones as the Garn barn.
I could have saved money in a couple of areas. For example, I could have put the manifold under the house in the crawl space. That alone could have saved me about 150' of pex, because I would have only had one loop from the manifold to the Garn barn instead of four loops. However, I didn't want the pumps and the manifold under the house in the crawl space. I wanted it somewhere where we would have easy access for any repairs. We are using the Garn barn to hold all the mechanical. The crawl space is only about 3-4' high. Just not an ideal working space. So, since everything had to be consolidated at a manifold, that was going to be in the Garn barn or the garage. They are both the same distance from the other zones, so we just decided to consolidate everything in the Garn barn.
I could have also saved pex in another area by consolidating two of the zone loops into one single loop. We have two runs that are parallel for a good distance, those zones are for DHW and the furthest heating zone to the west. We could have made one long run, then split off the DHW and send a supply/return to the furthest heating unit and then back. Basically the DHW is "on the way" to the furthest heating unit. It would have saved a lot of money on pex. Dang, those are long runs!
I'm passing on combining for two expensive reasons. First, if anything happened to me, I want a system that is super convenient for my wife and easy potential home-buyer to understand. My wife is a real smart lady, and that's not a slam on her. I want a system that isn't threatening or complicated for a potential home-buyer. It's just easy to say, "when it warms up in the spring, go to the Garn barn, and shut off these three valves and pumps that feed the heating system"...done. Not, go up on an eight foot step ladder, see those valves in the ceiling, turn them off, then go to the Garn barn and turn off these two valves and pumps. At the end of the day, it's another $200 in pex and a $80 pump to have them all terminate in the Garn barn and it makes the set up very easy to understand and super simple to run. Heck...I'm dropping over $20,000 on this entire set-up, I'm not going to nickel and dime over $300. Fortunately, we've done all the labor so far, so we are staying under budget, and you just saved me from buying a mixing valve! Secondly, in the summer, any pex line connected to the DHW is going to carry heat into my flooring. If I split off the DHW, the pex would run through the basement ceiling (upstairs flooring). I know we could install bypass valves that could be shut off...that takes me back to the first reason. I also wanted to make that DHW run as short and direct as possible since I'm running DHW year-round. I'm trying to keep it out as much radiant heat as possible on that DHW run. I'll shut down all three heating zones completely, and only run DHW in the summer.
A few nice things things that have worked our for us. We've been able to run each loop with zero fittings. Pex isn't known to fail, but when it does, it is almost always at a fitting. Since the manifold is in the Garn barn, I was also able to bypass the expense of a $250 primary loop pump. Another nice feature, when the house was built, they put an exterior exit off the man's master closet on the east side. It's basically a separate mud room in the man's master closet. That door opens up onto a deck (yet to be built) that will go right out to the Garn barn. Sure makes for easy access.
![Garn Owners - please give me some advice Garn Owners - please give me some advice](https://www.hearth.com/talk/data/attachments/117/117278-0670b8c16646bfe2b71ba7b73c4d07cf.jpg)
It's a work in progress. ...and we are making progress.
Hopefully this makes sense. Heaterman - thanks for all the input you've provided on other posts. I've read nearly all of them!