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IM 930-6
•
Enfinity Vertical Water Source Heat Pumps
8
www.DaikinApplied.com
Ventilation Air
Outside air may be required for ventilation. The
temperature of the ventilation air must be controlled so
that mixture of outside air and return air entering the
unit does not exceed application limits. It is also general
practice to close off the ventilation air system during
unoccupied periods (night setback).
The ventilation air system is generally a separate
building subsystem with distribution ductwork. To provide
thorough mixing of the outside and return air, introduce
the outside air in close proximity to the return air plenum
inlet. Do not duct outside air directly to the unit inlet. See
"Operating Limits" on page
9
.
Prior to making piping connections, contractor must clean and
flush water loop system. Failure to clean/flush system may result
in nuisance tripping and premature component failure.
CAUTION
Cleaning & Flushing Water System
1 .
Prior to first operation of any unit, the water
circulating system must be cleaned and flushed of
all construction dirt and debris.
If the units are equipped with water shutoff valves,
either electric or pressure operated, the supply and
return runouts must be connected together at each
unit location. This will prevent the introduction of dirt
into the unit. See Figure 7.
Figure 7: Connect the runouts together
Return Runout
Supply Runout
Mains
Flexible Hose
Runouts Initially
Connected Together
2 .
Fill the system at the city water makeup connection
with all air vents open. After filling, close all air vents.
The contractor should start main circulator with
the pressure reducing valve open. Check vents
in sequence to bleed off any trapped air, ensuring
circulation through all components of the system.
Power to the heat rejector unit should be off, and the
supplementary heat control set at 80°F (27°C).
While circulating water, the contractor should check
and repair any leaks in the unit and surrounding piping.
Drains at the lowest point(s) in the system should be
opened for initial flush and blow-down, making sure city
water fill valves are set to make up water at the same
rate. Check the pressure gauge at pump suction and
manually adjust the makeup to hold the same positive
steady pressure both before and after opening the drain
valves. Flush should continue for at least two hours or
longer until the drain water is clean and clear.
Units must be checked for water leaks upon initial water system
start-up. Water leaks may be a result of mishandling or damage
during shipping. Failure by the installing contractor to check for
leaks upon start-up of the water system could result in property
damage.
CAUTION
3 .
Shut off supplemental heater and circulator pump
and open all drains and vents to completely drain
down the system. Short circuited supply and return
runouts should now be connected to the unit supply
and return connections. Do not use sealers at the
swivel flare connections of hoses.
4 .
Flush system with water for 2 hours or longer until
water is clean.
5 .
Refill the system with clean water. Test the water
using litmus paper 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. Do not use
automotive grade antifreeze.
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.
Note:
Contact a local water treatment company to con-
firm water clarity prior to unit operation.
Dirty water will result in system wide degradation
of performance and solids may clog system-wide
valves, strainers, flow regulators, etc. Additionally, the
heat exchanger may become clogged which reduces
compressor service life or causes premature failure.
6 .
Set the loop water controller heat add setpoint
to 70°F (21°C) and the heat rejection setpoint to
85°F (29°C). 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) and the vented
air and loop temperatures have been stabilized,
each of the units will be ready for check, test and
start-up, air balancing, and water balancing.
