help with plumbing in S260

Hey guys. My new boiler was picked up today for delivery to me hopefully Monday. Im posting some pics of my existing plumbing that takes care of all my Radiant heating. Im looking for a good solution to hook up the S260 boiler to the existing plumbing while still being able to use by propane tankless water heater as a backup. The pics aren't the best but I hope that they will work. The boiler is going outside in an empty building about 20' from where you see the pex entering the wall. I was also wondering where I should put the circulation pump (basement or outside) and does it go on the supply or return? Is there anything wrong with wiring it up to run continusly? thanks for any help

I can't even figure out how your existing setup is working. Where is the air separator and expansion tank? It looks kind of like a primary secondary setup...but I don't see a circulator in the main loop? The pex you want to use for the S260...is it 1"?

markviii wrote:I can't even figure out how your existing setup is working. Where is the air separator and expansion tank? It looks kind of like a primary secondary setup...but I don't see a circulator in the main loop? The pex you want to use for the S260...is it 1"?

There is a circulator in the tankless water heater box. There is no expansion tank and I was told there is no need for one on the 260. Yes it is 1" pex that's coming from the boiler. The more I look at it the more I think I just need to pay a real plumber as much as I don't want to

I don't know who told you there is no need for an expansion tank on a closed hydronic system, but that is flat out wrong. You definitely need to add one to the system, and it will need to sized for the house sytem + the S260. An Extrol 90 or a floor-mounted commercial expansion tank would be my choice. You can tie the S260 in by putting another set of closely spaced tee's in your primary loop.

Also, I hate to be the one to tell you this, but 1" pex can effectively move about 80,000 btu's per hour. Hopefully that is enough to heat your home! The S260 will be loafing most of the time unless you plan on connecting additional loads to it in the outbuilding.

One more question...how is your domestic water heated?

[quote="markviii"]I don't know who told you there is no need for an expansion tank on a closed hydronic system, but that is flat out wrong. You definitely need to add one to the system, and it will need to sized for the house sytem + the S260. An Extrol 90 or a floor-mounted commercial expansion tank would be my choice. You can tie the S260 in by putting another set of closely spaced tee's in your primary loop.

Also, I hate to be the one to tell you this, but 1" pex can effectively move about 80,000 btu's per hour. Hopefully that is enough to heat your home! The S260 will be loafing most of the time unless you plan on connecting additional loads to it in the outbuilding.

One more question...how is your domestic water heated?[/quot


The domestic water is heated by another but smaller tankless water heater. I ordered the 260 with a domestic coil to take care of it. Currently there is approx 4500 sq ft that I'm heating and will be adding another 1000 sq ft next year. I can't believe all the diff stories Ive gotten on what I need and don't need. I'm not talking about you. I'm talking about a few " professionals" I've asked.

What size pex would you recommend? I bought this place in April and it is as you see it. The former owner used 2000 gallons of propane last winter and I wanted to save some money. I hope this all works out in the long run. Thanks for the help and please keep it coming