System Charging Procedures; Water-Water/Glycol Systems; Refrigerant Charging; Estimating Refrigerant Charge - Trane CyberAir DX Installation, Operation And Maintenance Manual

Perimeter precision air conditioners 21-105 kw / 60 hz
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Installation

System Charging Procedures

Water-Water/Glycol Systems

All self-contained water-water/glycol cooled units (units
that require no refrigerant field piping) are factory charged
with R-410A refrigerant. No field charging is required. The
following precautions must be observed when installing
and filling the water/glycol loop:
The piping system must be cleaned prior to adding
water/glycol to the system.
Glycol must be mixed with water before it is added to
the system. All air must be bled from the piping
system. Use only water/glycol solution with inhibitors
for corrosion protection.
NOTICE
Equipment Damage!
The piping system must be flushed prior to operating
the system. Failure to do so will result in equipment
problems.
1. Open the vent valve at highest point of the system.
2. Fill the system until the solution is discharging from
the vent with minimal signs of foaming due to air in the
system.
Pump
NOTICE
Pump Damage!
Do not run the pump dry.
If a pump is to be used, ensure the system is filled before
turning the pump on. The pump is not self- priming so it is
important that there is a pressure on the suction inlet.
If the pump has no pressure on the discharge side, leave
the discharge valve partially shut to create a back pressure
in the pump so that liquid can build up in the impeller
housing to keep the impeller housing from getting too hot.
Make sure there is always liquid flowing through the pump
to cool the impeller and housing. If there is no liquid
leaving the pump, shut the pump off immediately to
prevent damage to the pump. Check for proper rotation of
the motor observing the arrow on the side of the impeller.

Refrigerant Charging

Remote Air-Cooled Systems
Remote air-cooled systems are provided with a dry
nitrogen holding charge which must be removed before
piping and charging the unit. Before charging, check the
unit nameplate to confirm that charging is performed with
the correct type of refrigerant. CyberAir systems utilize R-
410A refrigerant.
30
Note: Refrigerant charging must be performed by a
qualified air conditioning technician.
R-410A is a blended refrigerant recognized for being safer
for the environment. Refrigerants that are multi-
component blends have component parts with different
volatilities that result in a change in composition and
saturation temperature as evaporation and condensation
occur. The composition of liquid
R-410A refrigerant however, remains relatively constant.
NOTICE
Equipment Damage!
POE oil is used in systems with R-410A refrigerant. POE
oil quickly absorbs moisture when exposed to air. High
POE oil moisture levels react with refrigerant to form
acid, which results in system contamination. Keep
entire system sealed as much as possible and minimize
exposure of POE oil to outside air.
R-410A operates at high pressures which must be
considered when checking the operating temperatures/
pressures while charging or troubleshooting the system.
Tables are provided in Section 2.9.6 showing the
temperature/pressure characteristics for R-410A.

Estimating Refrigerant Charge

When charging a system with R-410A refrigerant it will be
necessary to weigh in the refrigerant and confirm the
charge is correct by checking the superheat and
subcooling temperatures (see Section
Temperature Settings," p.
You can estimate the amount of refrigerant needed by
adding the amount of refrigerant required for the A/C unit
(Table 2, p.
31) plus the condenser
interconnecting refrigerant piping between the A/C unit
and the condenser
(Table 4, p.
The values in the tables are the estimated weights for the
refrigerant circuits. Depending upon site specific
conditions, refrigerant may need to be added or removed
when fine tuning the charge to obtain the correct
superheat and sub-cooling temperatures.
"Pressure/
34).
(Table 3, p.
31) plus the
32).
SS-SVX002B-EN

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