Comfort-Aire CMA36SB-1 - Manual (Page 11)

11
Heat Controller Horizontal/Side Discharge Condensing Units
The length of refrigerant lines and the number of
bends determine the pressure drop which affects
capacity and efficiency of the system and oil return
to the compressor. The outdoor unit connections
are flare type. Tube size should always be the
same diameter as the connections provided at
the service valves. Up sizing of lines can result
in inadequate oil return to the compressor and
excessive refrigerant charge and will void the
warranty [See Table 1].
Choose a location that places the condensing
unit as close to the indoor unit as possible. The
maximum separation is dependent on model.
Use only clean refrigeration grade tubing. Avoid
piping on wet or rainy days. Always keep the tube
ends capped until you are ready to make the final
connections. Remove burrs from cut ends of tubing.
Use tube benders to avoid kinking.
Insulate the suction line with Armaflex or equivalent
with a wall thickness of at least 3/8”. Support the
tubing adequately to avoid sags that can trap oil.
Isolate the tubing so as not to transmit noise to the
building structure. Avoid sharp edges that could cut
the tubes. Maximum vertical lift (compressor above
evaporator) is dependent on model. Trap risers with
a ‘P’ trap every 10 feet.
REFRIGERANT PIPING
LEAk TEST,
EVACUATION
& RELEASE OF
REFRIGERANT
The condensing unit is supplied with R-410a
charge sufficient for most matching evaporator
units. Charge must be added for interconnecting
tubing.
The unit’s service valves are shipped in the closed
position and should not be opened until final
connections and evacuation are completed.
The recommended procedure for leak test,
evacuation, and release of refrigerant is
outlined below:
1. Complete the final piping connections to the
indoor and outdoor units using high temperature
brazing alloy.
2. Connect a charging manifold to the service ports
provided at the service valves.
3. Pressurize the lines and evaporator with
nitrogen and leak check all connections with
soap bubbles. Repair as necessary any
faulty joints. If brazing is required be sure to
RELEASE THE NITROGEN FIRST. Re-test as
needed.
4. Connect a vacuum pump to the manifold center
connection, start the pump and open the
manifold valves.
5. Evacuate to 500 microns or less for a minimum
of 30 minutes. Close the manifold valves and
shut off the pump. Note the vacuum reading and
wait 15 minutes. Take a new vacuum reading. A
reading of 800 microns or higher indicates the
presence of moisture or a leak.
6. Repair as necessary and repeat steps 3, 4 & 5.
7. Confirm that manifold valves are closed and
disconnect the vacuum pump.
8. Remove the caps from the services valves.
Open the valves to the fully ‘back-seat’ position.
Replace service valve caps and tighten.
WARNING
It is illegal to discharge refrigerant into the
atmosphere. Use proper reclaiming methods
and equipment when working on the refrigerant
containing parts of the unit. Service should be
performed by a QUALIFIED service agency and
certified technicians.
Refrigerant Piping
Model No.
CMA 18 CMA 24 CMA 30 CMA 36
Liquid-Gas In. 1/4 - 1/2 3/8 - 3/4
Max. Refrigerant
Line Length*
Ft. 82 98
Max. Elevation
Vertical Lift**
Ft. 33 49
*Minimum pipe length must not be less that 15 feet.
** “P” trap risers every 10 ft. when outdoor unit is installed
above indoor unit.