Pressure Testing

Pressure Testing and Start-Up ⇒ The earth coil shall be pressure tested before connecting it to the heat pump and prior to complete backfilling. The piping shall be filled with water and/or air and pressure tested to 80-100 psi for at least 30 minutes. A visual inspection shall be made for leaks. Vertical U-bend assemblies shall be pressure-tested before insertion into the borehole. ⇒ When pressure testing is complete and a leak-free system is ensured, the system shall be thoroughly purged to remove air and debris. The preferred purging method is to use a flush cart consisting of a 1-1/2 to 2 HP water pump, tank, filter, flow meter, and flexible hose with connections. A minimum fluid velocity of 2 feet per second is required to purge the system of trapped air. The system circulating pump(s) cannot provide enough flow to remove pockets of trapped air out of the system.  ⇒ After the system has been filled and purged, it shall be pressurized as recommended by the heat pump manufacturer. Suggested pressures are 60 psi if installed during the heating season and 40 psi if installed during the cooling season.
Variable Speed Heat Pumps (VSHP). This section pertains to the installation of variable speed (compressor and fans) heat pump systems. All other sections of these standards are applicable unless otherwise noted. 1. The variable speed heat pump at high speed shall meet the required sensible and latent load of the structure as stated in the Equipment Requirements section. However, when the high speed sensible capacity exceeds the sensible load by 125 percent, the unit having a high speed sensible capacity closest to the sensible load shall be installed