f.
Connecting piping
g.
Connecting hoses
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NOTE: In larger systems with high horsepower
circulating pumps, air ejectors, and valved-off 35.2
kilowatt 10 ton header systems, a portable purge
pump may not be necessary if the ground heat
exchanger and indoor piping is free of debris and
other construction material.
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Using a purge pump and the procedures recommended by IGSHPA 21020, flush
and purge each ground heat exchanger system until free of air, dirt, and
debris. A velocity of 0.6 m/sec 2 feet/sec is required in pipe sections to
remove the air.
Perform the flushing and purging operation with the water source heat pumps
isolated by shutoff valves from the ground heat exchanger system. Allow
purge pump to run 15 minutes after the last air bubbles have been removed.
After the ground heat exchanger is completely flushed of air and debris,
open the isolation valves and permit circulation through the heat pumps
until the entire system is flushed and purged.
Utilizing the purging unit and the procedures recommended by IGSHPA 21020,
conduct a pressure and flow test on the ground heat exchanger to ensure the
system is free of blockage. If the flow test indicates blockage, locate
the blockage using the manufacturer's recommendation, remove the blockage,
then repeat the purge procedure and conduct the pressure and flow test
again until all portions of the system are free flowing. The flow test
shall be observed and approved by the Contracting Officer.
After purging has been completed, add the required amount of antifreeze to
the system. [Fill the open reservoir with the quantity of antifreeze
required for -9 degree C 15 degree F freeze protection and run the purge
pump 15 minutes to deliver the antifreeze to the system. Test the solution
with a hydrometer to determine the actual freezing point.]
Form 1, "Ground Heat Exchanger Inspection and Test Report" located below,
shall be completed for each system by the [Contractor] [or QC Manager]
after completion of the flow [and injection of required antifreeze to the
system and] before the systems can be backfilled.
SECTION 15741N
Page 34
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