circulator size and hi-lo settings

HexHighway

I have a client who owns a 3000 sf masonry home, and has oiled fired hydronic heat. The mains are 3" (formerly steam?) and the radiators at the end of the runs don't get super hot before the thermostat is satisfied (one zone).

It has one 007 Taco circulator and the aquastat is set at 160-180 with the diff at 20.

Is there any point in getting a larger circulator or upping the hi-lo or that wouldn't make an effective differrence?

It's just two of maybe 20 radiators that don't get very hot because they are the last on the run ...

So, what determines how you set the hi-lo and diff? And does the circulator size matter in a case like this? Thanks

Steamhead

If the supply and return are the same size

it was originally a gravity hot-water system, which did not use a pump.



Measure the square feet of radiation on that system, then use this chart to select the proper circ:



http://www.heatinghelp.com/article/343/Circulators/238/Sizing-Circulators-for-Hot-Water-Heating-Systems

HexHighway

Thanks!

Very helpful. Great place to start. Thanks.