If you planned for 180° F water at a radiator or convector, and you actually have 140° F water at the last unit (40° F drop in temperature), you aren't heating that last room as much as you had planned to.
You'll overheat the rooms at the beginning of the loop, to the point that you'll be tempted to REMOVE some of the radiation.
Hydronics = Math Do the math.
Figure the head. Figure the gallons of liquid in the system. Factor in how quickly you want all of that water to totally circulate through the system (GPM). Go to the pump curves of your favorite manufacturer and figure out what pump will do it.
I wonder at what size the boiler manufactures quit putting 007's on the new boilers? When they can't get the correct flange combination to fit on the outlet piping anymore???
Oh..... I think it's the pump that's the problem. Came with the boiler... has to be the right size, right?
put any pump on the boiler that the customer orders.
We replace the boilers in our inventory as they get ordered and sold.
It really doesn't matter to us WHICH pump the wholesaler and contractor orders.
I wonder if "contractors shopping price" has any influence on which pump gets ordered by the wholesaler.
The order has a place for the part number for the boiler/burner/pump combination that the customer requests. There are 10 standard circulator choices available. The 100 and 110 are still available, in fact.