Table of Contents
Water System Cleaning
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 elec-
tric or pressure operated, the supply and return run outs
must be connected together at each unit location. This will
prevent the introduction of dirt into the water circulating
system. Additionally, pressure operated valves only open
when the compressor is operating.
NOTICE
It is Daikin's policy not to make recommendations on water
treatment. It is the responsibility of the user to check that
the water supply to the units is free of contaminants or cor-
rosive agents, chemicals or minerals. The general contrac-
tor or owner should contact a local water treatment com-
pany regarding water treatment. 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
CAUTION
Self-Contained WSHP Unit Ventilator Models ARQ, ERQ, GRQ
Figure 37: 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.
Units must be checked for water leaks upon initial water
system start-up. Water leaks may be a result of mishan-
dling 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.
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.
Mains
CAUTION
CAUTION
Page 21 of 42
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