restrictive tank?

paul thompson

i just unwrapped my 100 gal water tank, it has 2 coils inside, one for boiler heat, and the other for solar.
only snag is....the inlet and outlet holes in the coils are teeny. i have a 1" solar line coming in, and now it is going to constrict to what appears to be about 3/8" ID.
im just guessing, but wont that slow down the solar loop considerably, possibly making it overheat? the other loops in the system, for example a large heat storage tank, have 1" coils through them, and now i find this. if i bump up the pump speed to overcome this constriction, then i guess it will run too fast for everything else.???????? target gpm on the solar panels is 6.

Brad White_84

For the required flow rate, Phil

That seems a little tight but may be just fine. For all you know the connection size is just a two-point restriction (the in and out connections) and is bushed down for metal strength at the connection to the tank wall. The internal coil might well be larger for the greater distance, I really do not know.

Often equipment connections are smaller than the "travelling" line size, although I admit that the contrast in yours is wider than I usually see. Often a given connection size just happens to be one or two sizes smaller than the feeding line size.

In your case it seems that your one-inch line size is appropriate though.


But the core point is, so long as you can deliver the flow rate and meet the pressure requirements (you have to do both of course- duh! Why did I state that?) you will be fine. Just accept the flow rate and pressure drop as a base-line expenditure; you just have to do that.

One other point: Without a diagram of your system set-up, if the other components in parallel have much lower pressure drops, prepare to add balancing valves to the large-tube components so you can get the required flow to this presumed "path of greatest resistance".