Johnson Controls YC4 Series - Brazing the Refrigerant Lines and Service Valves

Brazing the refrigerant lines and service valves
About this task:
It is important to take the necessary precautions for brazing the refrigerant lines and service valves.
All outdoor unit and indoor coil connections are copper-to-copper and you must braze them with
a phosphorous-copper alloy material such as Silfos-5 or equivalent. Do not use soft solder. These
outdoor units have reusable service valves on both the liquid and vapor connections. The total
system refrigerant charge is retained within the outdoor unit during shipping and installation. The
reusable service valves are provided to evacuate and charge as outlined in this manual. You can
avoid serious service problems by taking adequate precautions to ensure an internally clean and
dry system.
CAUTION
The indoor coil is under inert gas pressure. Relieve pressure from the coil by depressing the Schrader
core at the end of the suction manifold stub out. Dry nitrogen must always be supplied through the
tubing while it is being brazed because the temperature required is high enough to cause oxidation
of the copper, unless an inert atmosphere is provided. The flow of dry nitrogen must continue until
the joint cools. Always use a pressure regulator and safety valve to insure that only low pressure
dry nitrogen is introduced into the tubing. Only a small flow is necessary to displace air and prevent
oxidation.
CAUTION
Do not install any coil in a furnace which is to be operated during the heating season without attaching
the refrigerant lines to the coil. The coil is under pressure which must be released to prevent excessive
pressure build-up and possible coil damage.
CAUTION
Do not connect manifold gauges unless trouble is suspected. Approximately 3/4 oz of refrigerant is lost
each time a standard manifold gauge is connected.
WARNING
Never attempt to repair any brazed connections while the system is under pressure. Personal injury
could result.
Take the following precautions when brazing the service valves:
• Wrap a wet rag around the service valve to prevent heat damage, as shown in Figure 9.
• Protect items such as painted surfaces and insulation during brazing.
• After brazing, cool the joint with a wet rag.
Installation Manual: R-454B Outdoor Split-System Air Conditioner26
Johnson Controls Ducted Systems