Garn Plumbing Plan Opinions?

[Sawyer]

Well the Garn Barn is mostly ready and I am finally getting my design in shape and am anxious to order the parts.

With all measuring complete the first loop, design load 93,000BTU to the house will be 400’ of tandem 1” PEX with 20’ of 1-1/2” black pipe. My calculations come to approximately 4.5gpm=5.29psi=12.2’ head on each 1” loop. When I size for one pump pushing both lines at 10gpm, I came to 15’ head. These include 1.4’ head for the GEA HX.

The second loop to the shop will be 100’ of ¾” PEX and 20’ of black pipe. With a design load of 32,000BTU I calculate 3.2gpm @ 6.5’ head. I plan to use one Grundfos 15-58FC .

I would like to use 2- Grundfos 15-58FC’s, one on each 1” PEX supply line (I could push 5gpm if necessary) to the house if necessary. This would allow 5 out of six pumps in the system to be 15-58’s with one 0011 on the in-floor loop. I will also have the ability to run one pump in the shoulder seasons and in the summer for domestic water and reduce energy consumption. I will use flanges with drains.

If I am installing nothing but brass ball valves and brass boiler drains on the black pipe is it necessary to install dielectric fittings?

I have attached two diagrams that I hope will help clarify my plan……….which is definitely open to new ideas and changes. I apologize for the format; I wish I had a program that would design with standardized symbols. The supply to the shop in the fittings diagram should be plumbed after the house supply to provide the hottest water to the house but the fittings should be very similar.

 

[Gooserider]

I see one major problem - in the house diagram, you appear to have close space tees going to the DHW and Furnace HX coils, controlled by zone valves... The problem is that water is lazy, and is not going to go through those ZV's and the loads, when it has a straight shot through the tees... (That's the whole idea of the close space tees concept, as it isolates the side loops from the main loop) You need to either replace the ZV's with pumps, or come up with a different approach on the plumbing loop.

Also unless your house boiler needs to be kept hot in order to function, I would consider trying to bypass it other than when it is actually running, the same way you do with the shop.

I don't see any other major issues off hand.

If you have brass fittings going to iron pipe, you aren't supposed to need dielectric fittings, as the brass is supposed to serve the same function. You only need dielectrics if going directly from iron to copper (or you can do Iron-brass-copper). However I seem to recall that Garn wants you to have a certain minimum length of black iron pipe before you have any brass or copper fittings.

Don't worry overly much about the format - it is better than some of the hand-drawn stuff that I've seen posted. If you really did want to get fancy, you could look into some of the free / open-source CAD programs out there. I know you can download some neat stuff from Taco and some of the other vendors if you are on the defective O/S, or I've had good luck using Q-CAD on Linux.

Gooserider

 

[ewdudley]

...
I know you can download some neat stuff from Taco and some of the other vendors if you are on the defective O/S
...
Gooserider

Art,

Maybe give WINE another shot at the Taco stuff. The error messages make it clear what DLLs are missing and you can get them straight from MS themselves. Or at least this was my experience running under Ubuntu / Linux dell-desktop 2.6.24-16-generic #1 SMP Thu Apr 10 13:23:42 UTC 2008 i686.

--ewd

 

[Sawyer]

I see one major problem - in the house diagram, you appear to have close space tees going to the DHW and Furnace HX coils, controlled by zone valves... The problem is that water is lazy, and is not going to go through those ZV's and the loads, when it has a straight shot through the tees... (That's the whole idea of the close space tees concept, as it isolates the side loops from the main loop) You need to either replace the ZV's with pumps, or come up with a different approach on the plumbing loop.

Thanks Gooserider. I will change the plumbing loop and keep the zone valves.

Also unless your house boiler needs to be kept hot in order to function, I would consider trying to bypass it other than when it is actually running, the same way you do with the shop.

Garn specified at least 6' of black pipe before a dielectric fitting but did not address the brass and black pipe without any copper.

I will by pass the boiler. I was being lazy and trying to use the pump on the boiler.

 

[Sawyer]

I see one major problem - in the house diagram, you appear to have close space tees going to the DHW and Furnace HX coils, controlled by zone valves... The problem is that water is lazy, and is not going to go through those ZV's and the loads, when it has a straight shot through the tees... (That's the whole idea of the close space tees concept, as it isolates the side loops from the main loop) You need to either replace the ZV's with pumps, or come up with a different approach on the plumbing loop.

Also unless your house boiler needs to be kept hot in order to function, I would consider trying to bypass it other than when it is actually running, the same way you do with the shop. Gooserider

I made the changes you suggested.