ok thanks robert

To get the full 250K BTU's / hour out of the M250 with a 10 gpm water flow rate, you have to use the 1.25" outlets and 1.25" pipe. That's why they have those outlets on the burner I suspect, so that they can claim to meet their specs. Regardless I've never read about anyone actually using 1.25" ThermoPex, it's just too expensive.

If we assume you are using 1" lines like 99% of the installs do, then just try to keep your run at short as possible with as few fittings as possible. Anything that restricts your water flow rate restricts your ability to deliver heat to your heat exchangers.

None of this is going to reduce your pellet or corn burn rate, you don't get BTUs for free, these are just some tips to insure you can get the heat where you need it.

The other thing is sizing your pumps correctly. That needs to be calculated based on the size of your lines, how long they are, the flow rate you want, how many fittings you have, etc. There is more information here:

taco-hvac.com/

I agree with 5520. Since the usage is on 85k btu 1" should be fine.

Thx alot. But would the best thing to do for efficience and btu is to take the 1.25 lines from the boiler and directly to the buffer and directly back to the boiler again. Then run the other lines off of it.Thx

Hi guys thx for your posts. I am getting the heat i need with 1 inch lines but i want to try to get the most efficient way to.Thx

You might want to see what i found on my thread ... Loss of power to Fire Star controller .. but make sure your unit is off of warranty as i'm sure CB woudn't someone poke in there controller