Pump Location

J Van Lund · December 2003

1) I have a small in-floor hydronic heating system (1500 sf) which has a Grundfos UP15-42SF circulator, which meets the system's circulating needs. We can mount it in a horizontal or vertical run of pipe. Will it perform better in the vertical run of pipe or the horizontal?

2) We read there should be a straight run of pipe equal to ten pipe diameters between the pump inlet and a 90 degree bend to avoid cavitation problems. So for a 3/4-inch diameter inlet pipe, there should be at least 8 inches of straight pipe before the 90 degree bend. Do you agree?

3) Should the same rule apply to the outlet side of the pump?

4) In a closed or dedicated system, does it matter if you pump toward the expansion tank or away from it? Everything we have read indicated that Rule #1 in hydronic heating is to always pump away from both the expansion tank and air separator. Do you concur?

Thanks for your help.

Alan(CaliforniaRadiant)Forbes · December 2003

Some answers

1) Vertical or horizontal makes no difference, just make sure the shaft of the motor is horizontal.

2) Yes, I agree.

3) No; there aren't so many rules for the discharge side of the circulator.

4) Yes, pump away from the x-tank which is usually (but not always) attached to the air separator.

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Pump Location

Comments

Categories