Geostar Arbor Base Series, Installation Manual

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14
ARBOR BASE SERIES INSTALLATION MANUAL
System Cleaning and Flushing
Cleaning and Flushing
Prior to start up of any heat pump, the water circulating system
must be cleaned and flushed of all dirt and debris.
If the system is equipped with water shutoff valves, the supply and
return runouts must be connected together at each unit location
(This will prevent the introduction of dirt into the unit, see Flushing
with Water Shutoff Valve Equipped Systems illustration). The
system should be filled at the water make-up connection with all air
vents open. After filling, vents should be closed.
The contractor should start the main circulator with the pressure
reducing valve makeup open. Vents should be checked in
sequence to bleed off any trapped air and to verify circulation
through all components of the system.
As water circulates through the system, the contractor should
check and repair any leaks found in the piping system. Drain(s) at
the lowest point(s) in the system should be opened for initial flush
and blowdown, making sure water fill valves are set at the same
rate. Check the pressure gauge at the pump suction and manually
adjust the make-up water valve to hold the same positive pressure
both before and after opening the drain valves. Flushing should
continue for at least two hours, or longer if required, until drain
water is clean and clear.
The supplemental heater and/or circulator pump, if used, should
be shut off. All drains and vents should be opened to completely
drain the system. Short-circuited supply and return runouts should
now be connected to the unit supply and return connections.
Refill the system with clean water. Test the system water for acidity
and treat as required to leave the water slightly alkaline (pH 7.5 to
8.5). The specified percentage of antifreeze may also be added
at this time. Use commercial grade antifreeze designed for HVAC
systems only. Environol™ brand antifreeze is recommended.
Once the system has been filled with clean water and antifreeze
(if used), precautions should be taken to protect the system
from dirty water conditions. Dirty water will result in system-wide
degradation of performance, and solids may clog valves, strainers,
flow regulators, etc. Additionally, the heat exchanger may become
clogged which reduces compressor service life and can cause
premature unit failure.
In boiler/tower application, set the loop control panel set points
to desired temperatures. Supply power to all motors and start the
circulating pumps. After full flow has been established through all
components including the heat rejector (regardless of season), air
vented and loop temperatures stabilized, each of the units will be
ready for check, test and start up and for air and water balancing.
Ground Source Loop System Checkout
Once piping is completed between the unit pumping system and
ground loop, final purging and charging of the loop is needed. A
high pressure pump is needed to achieve adequate flow velocity
in the loop to purge air and dirt particles from the loop itself.
Antifreeze solution is used in most areas to prevent freezing. Flush
the system adequately to remove as much air as possible; then
pressurize the loop to a static pressure of 40-50 PSI (summer)
or 50-75 PSI (winter). This is normally adequate for good system
operation. Loop static pressure may decrease soon after initial
installation, due to pipe expansion and loop temperature change.
Running the unit for at least 30 minutes after the system has been
completely purged of air will allow for the “break-in” period. It may
be necessary to adjust static loop pressure (by adding water) after
the unit has run for the first time. Loop static pressure will also
fluctuate with the seasons. Pressures will be higher in the winter
months than during the cooling season. This fluctuation is normal
and should be considered when charging the system initially.
Ensure the pump provides adequate flow through the unit by
checking pressure drop across the heat exchanger.
Usually 2.25-3.0 gpm of flow per ton of cooling capacity is
recommended in earth loop applications.
Return Runout
Supply Runout
Mains
Rubber Hose
Runouts Initially
Connected Together
Flushing with Water Shutoff Valve Equipped Systems