=+10-25.

Find the volume of a free surface expansion tank for a hot water system with a volume of 1500 gal (5.7 m3). The system gage pressure is regulated to 20 psi (140 kPa) at the tank and initially filled with water at 60 F (16 C). The pressure relief valve on the boiler is set for a gap-

pressure of 60 psi (414 kPa), and the maximum water temperature is expected to be 210

(99 C). The system is predominantly copper tubing.