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[wardk]

I have the garn barn partially finished,the underground pipes are in place,60ft to the shop , 100 ft to the house.My dealer looked at what I needed to do inside the house and shop and he suggested I hire a specialist to design the system, but I already have 22k into this project and the budget is a little  strained. I was really hoping that I could get some help here.The house is the main issue it has infloor heat in the basement slab currently heated with a hot waterheater supplemented with a coil in the wood forced air furnace ,the  house also has an older wing which we added onto, it's not insulated as  well.I need to install water to air heat exchanger for the forced air, side arm for dhw,2 iron heaters in the old wing and connect to the the infloorheat, Can anyone suggest a path for the water 1st 2nd etc.Sorry for the long winded post, thanks

[RSI]

You might want to think about using a plate heat exchanger instead of a sidearm. With a plate you will never run out of hot water but if you go a long time between running any hot water then the water heater might need to run a little to keep the tank warm.

It is kind of hard to say what is best without actually seeing how everything is layed out. Going off what you posted, I would probably go to the sidearm or plate first, then to the water to air coil. For the iron heaters and floor I put them on secondary loops. (2 tees in the main line close together)
I would put the connections for the iron heater loop after the water to air heat exchanger unless you need hotter water for them to operate best.
The floor loop should probably be last because you will run that at much lower temperature. It should also be on a secondary loop. Some people say the floor heat needs to be pressurized but I have not had any trouble leaving them direct connected to the open system.

[wardk]

thanks for the reply RSI, with the side arm or plate do you use a small pump to circulate the domestic hot through the exchanger?You mentioned going to two zones, do you think I could split the incoming lines as they enter the house 1in down to two 3/4in? The reason is 3/4in pex and fittings are less than half as much and are available anywhere around here.My last dumb question would you control the cast iron heaters with a mechanical valve or a thermostat controlled valve?Thanks

[RSI]

I would stay with 1". The fittings aren't that expensive for barb type.
With the secondary loop like I mentioned you need a separate pump for the loop. You can control the temperature of the cast iron heaters by controlling the pump on that loop with a thermostat. If the heaters aren't real big it would probably be fine to use 3/4" for that loop, just make sure you don't restrict the main loop at all where you connect to it.

You can use a small pump to circulate the DHW through the plate but not usually needed. With your garn it might not be a bad idea though if you let the temperature drop fairly low between burns.

[Radiantman]

Where are you located in the country?
I've been in the hydronic business for 30 years.  Possible know someone in your area.
Have to contacted your GARN Rep in your area. Many time they will help with concepts/designs.
In general I would agree with RSI regarding using a flat plat heat exchanger, it does make piping simpler with pressurized system.
Don't get overwhelmed with the whole project. Start with just one area and size your piping based on the heat load.
 Break down your project into smaller segments and you will be just fine
Good luck

[Radiantman]

A ton of great GARN owners on    http://www.hearth.com
Check out the Forum
I do agree all the Forums are a bit quit this time of the year. Its just to hot to think about heating.