I am building out my boiler room piping and have some basic questions. 1. Does anybody bother to insulate the primary loop piping? (I have seen dozens of install photos of all this bare piping, heat exchangers etc bolted to an exterior concrete wall! Seems incredible dumb). 2. Does anybody bother to use long radius elbows to reduce friction? 3. Does 1" primary piping seem sufficient for 25000BTUs and <4gpm? Just looking for a gross check before I commit to 1" vs. 1.25" primary piping. Thanks John7

I can't think of a reason not to insulate pipe that you want to maintain heat/temp. To the extent practical, it is always best to reduce pipe friction head loss so as to minimize the required pumping head and associated increased parasitic pumping energy loss. At < 4 GPM, your pipe friction head loss is going to be pretty small no matter what elbows you use. For example, 100' of 1" diameter pipe will have about 0.7 PSI of pipe friction head loss at 4 GPM. 100' of 1.25" diameter pipe will have about 0.2 PSI of pipe friction head loss at 4 GPM.

I thought my mechanical room would be too warm, but it isn't and that is what is slowing me down from insulating mine.

25mbtu what?

What will you be heating with it?

Insulating near piping is residential near piping is not done because the "loss" is too small to consider. All is in the envelope and with ODR the temperature differential--main factor in heat transfer--is also low.

As for long radius copper elbows. They are not used nor needed for the vast majority of residential hydronic heating work.

Your designer should have this worked out for you.

What would anyone be heating with a 125F DeltaT???? What ever it is, I doubt it will work.

BTU/Hr=DeltaT x GPM x 500

12.5

Oooops. I tossed an extra zero on the load. Thanks for the correction.