Specifications

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Cleaning & Flushing System
1. Priortorstoperationofanyconditioner,thewater
circulatingsystemmustbecleanedandushedofall
construction dirt and debris.
If the conditioners are equipped with water shutoff valves,
either electric or pressure operated, the supply and return
runouts must be connected together at each conditioner
location. This will prevent the introduction of dirt into the
unit. See Figure 11.
Figure 11: Supply & Return Runouts Connected 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lling,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ush
andblowdown,makingsurecitywaterll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 runouts
should now be connected to the conditioner supply and
returnconnections.Donotusesealersattheswivelare
connections of hoses.
4. Trisodium phosphate was formerly recommended as a
cleaningagentduringushing.However,manystatesand
localities ban the introduction of phosphates into their
sewage systems. The current recommendation is to simply
ushlongerwithwarm80°F(27°C)water.
5. Rell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specied
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lled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,ow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ow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.
Start-up
1. Open all valves to full open position and turn on power to
the conditioner.
2. Set thermostat for “Fan Only” operation by selecting
“Off” at the system switch and “On” at the fan switch. If
“Auto” fan operation is selected, the fan will cycle with
the compressor. Check for proper air delivery.
3. For those units that have two-speed motors, reconnect for
low speed operation if necessary.
4. Set thermostat to “Cool.” If the thermostat is an automatic
changeover type, simply set the cooling temperature to the
coolest position. On manual changeover types additionally
select “Cool” at the system switch.
Again, many conditioners have time delays which protect
the compressor(s) against short cycling. After a few
minutes of operation, check the discharge grilles for cool
air delivery. Measure the temperature difference between
entering and leaving water. It should be approximately
1½ times greater than the heating mode temperature
difference. For example, if the cooling temperature
difference is 15°F (8°C), the heating temperature
difference should have been 10°F (5°C).
 Withoutautomaticowcontrolvalves,targetacooling
temperature difference of 10°F to 14°F (5°C to 8°C).
Adjust the combination shutoff/balancing valve in the
returnlinetoawaterowratewhichwillresultinthe
10˚Fto14°F(5°Cto8°C)difference.