Water System Cleaning - Daikin ARQ Installation And Maintenance Manual

Water System Cleaning

CAUTION
Prior to first operation of any unit, the water circulating system
must be cleaned and flushed of all construction dirt and debris.
If the unit is provided with water shutoff valves, either electric or
pressure operated, the supply and return run outs must be con-
nected together at each unit location. This will prevent the intro-
duction of dirt into the water circulating system. Additionally, pres-
sure operated valves only open when the compressor is operating.
NOTICE
It is Daikin's policy not to make recommendations on water treat-
ment. It is the responsibility of the user to check that the water
supply to the units is free of contaminants or corrosive agents,
chemicals or minerals. The general contractor or owner should
contact a local water treatment company regarding water treat-
ment. A fouled closed loop water system will lead to premature
component failure.
The system water piping must be thoroughly cleaned and
flushed in order to remove dirt, chips or other foreign matter
before connecting to the heat pumps or starting the system.
Since the initial condition of the system water may be such
that dirt or other foreign matter may clog or otherwise damage
balancing and shutoff valves, it is recommended that these
valves be omitted during the cleaning of the water system as
outlined in the following procedure.
The entire system should be filled with clean, fresh water
and properly vented. Piping leaks should be repaired as
early in this procedure as they are discovered. With valves
positioned to bypass the heat pumps, heat rejector and the
supplementary water heater, the pump should be started to
circulate water through the system. Check strainers frequently
and clean as often as needed. If the water is extremely dirty
or murky, it is sometimes helpful to continuously flush, using
the system pump, until the water being flushed out of the pipe
loop has become clear. To flush in this manner requires care
to be certain that make-up water is being added fast enough to
replace what is being flushed out. This can be accomplished
by opening the make-up water bypass valve around the
automatic pressure reducer valve, adjusting the manual valve
so that the pump suction pressure gauge continues to indicate
the same positive pressure that existed before the manual
drain and make-up valves were opened. Continue for at least
two (2) hours.
To complete the cleaning, fill the system with fresh water,
adding a cleaning agent such as trisodium phosphate (TSP).
IM 1083-3
Figure 34: Connections for flushing system piping
Return Runout
Supply Runout
Flexible Hose
Runouts Initially
Connected Together
Bypass valves at the heat rejector and supplementary water
heater should be adjusted for normal operation. Disconnect
all power to the heat rejector and heat pump so that they will
not operate while the system is being cleaned. The cleaning
solution should then be circulated throughout the system, with
water heater controls temporarily adjusted to raise the solution
temperature to about 105°F to 110°F. DO NOT allow the
temperature to rise above 110°F, especially in systems using
plastic pipe. Alternate operation of the primary and standby
pumps, and circulate the warm solution for several hours.
Then turn off the water heater and pump, completely drain the
system and refill with fresh water. Repeat the cleaning process
only if there is indication of foreign matter still in the system, or
if a test of the water indicates that it is even slightly acid.
The water should be slightly alkaline, with a pH no higher than
8.0 and no lower than 7.0, which is neutral. Traces of TSP or
similar cleaning agent will tend to leave the water in a slightly
alkaline condition provided all acid forming substances such
as pipe coatings or flux have been properly cleaned out. A
tight system requiring little or no make-up water, with neutral or
slightly alkalline water, will remain in proper operating condition
indefinitely. The addition of chromates or other corrosion
inhibitors is NOT recommended, except when ethylene glycol
is added for freeze protection. IN ALL CASES, A WATER
QUALITY EXPERT SHOULD BE RETAINED TO MAKE A
WATER ANALYSIS .
Note: Contact a local water treatment company to confirm
water clarity prior to unit operation.
CAUTION
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
Water/refrigerant heat exchanger fouling will interrupt water flow
resulting in localized freezing. Install a 16-20 mesh strainer in the
water line upstream of the exchanger.
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Mains
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