Installation
60
RT-SVX24J-EN
If the rise exceeds this, there is either still moisture in
the system or a leak is present.
10. Charge the system per the unit nameplate field
charge.Do not add refrigerant in the suction line at this
time to prevent excessive refrigerant in the low side
prior to compressor startup.
11. At the liquid line angle valve add as much R-410A
LIQUID as possible. Depending on conditions, it could
not be possible to add more than 60% of the field
charge. This will be adequate for compressor
startup.More charge will be added after compressors
are started. Use an accurate scale to measure and
record the preliminary amount of R-410A added to
each circuit.
12. With all the circuit compressors operating, SLOWLY
meter R410-A into the suction line from the LIQUID
charging connection.
Evaporative Condenser Tubing Connection
Important:
For units with electric heat, complete tubing
connections AFTER completing wiring
connections. See
“Electric Heat Wiring
Connection” on page 61
section.
Important:
Complete tubing connections BEFORE
Power and Control wiring connections. See
“Power and Control Wiring Connections”
on page 61
section.
There will be a N
2
nitrogen charge in the air handler
section. This holding charge should be relieved prior to
removing the caps.
The condenser section will ship with R-410A throughout
the entire tubing assemblies. The service valves will be
shipped in an open position. Additional interconnecting
tubes (approx. 15-20" in length) will be supplied with the
unit.
1. To prepare the condensing section for the joining of the
two sections, the discharge and liquid line service
valves should be shut and the refrigerant remaining
between the valves and the end caps should be
transferred/recovered.
2. If the unit has been purchased with hot gas bypass or
hot gas reheat options, those valves should be shut as
well and the refrigerant transferred/recovered from the
sections between the valves and the end caps.
3. Remove the brackets which support the suction tubes
(retain for possible use later for unit reassembly) after
the tubing connections are complete.
4. Relieve the pressure (charge) for the section of the
tubing being worked on.
5. Place wet rags on the flow/ ball valve on the high side
when suction tubes are being brazed.
Note:
Additional care should be taken when brazing near
the wire bundle.
6. Sweat the copper caps off both the high and low side
of the suction and liquid lines of both circuits.
7.
Clean the joints of weld puddles to avoid insertion
problems.
8. Cut the appropriate interconnecting tube to a length
approximately 0.75"- 1" more than the distance
between the two tubes.
9. Insert the appropriate tube to the complete depth of the
bell on one side of the joint and align the other side
(prying the high side may be needed). Make sure the
insertion depth is met.
10. Complete the connections by brazing the tubes in
place.
Note:
Refrigeration ball valves are intended for general
service and are not a positive shutoff device.
11. Once all connections have been brazed, evacuate the
low side. The low side may be evacuated by the
schrader ports on the discharge line just past the
compressor and the liquid line below the sight glass.
See
Figure 37, p. 59
.
The recommended method for evacuation and
dehydration is to evacuate the low side to 500 microns
or less. To establish that the unit is leak-free, use a
standing vacuum test. The maximum allowable rise
over a 15 minute period is 200 microns. If the rise
exceeds this, there is either still moisture in the system
or a leak is present.
Note:
Only after evacuation should the tagged valves be
opened.
WARNING
Hazard of Explosion and Deadly Gases!
Never solder, braze or weld on refrigerant lines or any
unit components that are above atmospheric pressure
or where refrigerant may be present. Always remove
refrigerant by following the guidelines established by
the EPA Federal Clean Air Act or other state or local
codes as appropriate. After refrigerant removal, use dry
nitrogen to bring system back to atmospheric pressure
before opening system for repairs. Mixtures of
refrigerants and air under pressure may become
combustible in the presence of an ignition source
leading to an explosion. Excessive heat from soldering,
brazing or welding with refrigerant vapors present can
form highly toxic gases and extremely corrosive acids.
Failure to follow all proper safe refrigerant handling
practices could result in death or serious injury.
