IM 1059-12 LARGE VERTICAL WSHP
21 www.DaikinApplied.com
Cleaning & flushing system
1 .
Prior to first operation of any conditioner, the water
circulating system must be cleaned and flushed of
all construction dirt and debris.
If the conditioners are equipped with water shutoff
valves, either electric or pressure operated, the supply
and return run-outs must be connected together
at each conditioner location. This will prevent the
introduction of dirt into the unit (
Figure 15
).
Figure 15: Supply & return run-outs connected together
Return Run-out
Supply Run-out
Mains
Flexible
Hose
Run-outs 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 piping. Drains at the lowest
point(s) in the system should be opened for initial
flush and blowdown, 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 if required, to see clear, clean drain water.
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
run-outs should now be connected to the conditioner
supply and return connections. Do not use sealers
at the swivel flare connections of hoses.
4 .
Trisodium phosphate was formerly recommended
as a cleaning agent during flushing. However,
many states and localities ban the introduction of
phosphates into their sewage systems. The current
recommendation is to simply flush longer with warm
80°F (27°C) water.
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.
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 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 air vented
and loop temperatures stabilized, each of the
conditioners will be ready for check, test and start-
up, air balancing, and water balancing.
Operating limits
Information for initial start-up only
Standard range units:
Units are designed to start in an ambient of 50ºF (10ºC),
with entering air at 50ºF (10ºC), with entering water at
70ºF (21ºC), with both air and water at the flow rates used
in the ISO 13256-1 rating test, for initial start-up in winter.
Note:
This is not a normal or continuous operating
condition. It is assumed that such a start-up is for
the purpose of bringing the building space up to
occupancy temperature.
Extended range units:
Extended range heat pump conditioners are designed
to start in an ambient of 40ºF (5ºC), with entering air at
40ºF (5ºC), with entering water at 40ºF (5ºC), with both
air and water at the flow rates used in the ISO 13256-1
rating test, for initial start-up in winter.
Note:
This is not a normal or continuous operating
condition. It is assumed that such a start-up is for
the purpose of bringing the building space up to
occupancy temperature.
u
nit
i
nstallation
