To calculate the total equivalent
length, the equivalent lengths of all
fittings in a pipe run must be added to
the actual length of pipe in the run:
these are the fittings most likely to be
used.
R = Radius of bend
d = Diameter of tube
C = Centres of bend
A. SUCTION AND LIQUID/EXPANSION LINES:
The expansion capillary is located in the outdoor unit and the equivalent pipe run is 15m maximum, including
a maximum lift of 7.5m. Fully insulate the suction and liquid/expansion line. Ensure the suction pipe is
insulated well over the drain tray at the indoor unit. Liquid lines should be routed to avoid hot areas. This
prevents flash gas forming, which may result in erratic control of liquid refrigerant to the evaporator.
For systems with interconnecting pipework in excess of 7.5 metre add 20gms per metre on
CKA 35 & CKA 50, add 30gms per metre on CKA 70. No additional oil is required.
INTERCONNECTING PIPEWORK
1. Indoor and outdoor units have a low pressure charge of N2, which may be safely released into the
atmosphere before connection. The service valves on the outdoor unit should remain closed (IN, fully
clockwise) until pipework has been fitted, to avoid unnecessary moisture ingress.
2. Connecting the pipework
a. Remove the flare nuts from the suction and liquid service valves.
b. Ensure that the suction line is fully insulated: if an expansion line is used this should also be fully
insulated.
c. Place the flare nuts over the incoming pipework and flare the pipe ends. The use of a little
refrigeration oil on the flaring tool will help.
d. Connect the pipework between the units. Do not leave pipe ends, valves etc. open to the
atmosphere.
R410A is very hygroscopic, and will absorb damaging levels of moisture if left open.
Always use two spanners when tightening the flare nuts to avoid twisting the pipes. Use a small
amount of refrigerant oil on the mating surfaces.
e. Sight glasses and filter driers are not necessary, but if required should be fitted between the
outdoor unit liquid shut off valve and the expansion device.
EVACUATING
1. Release the nitrogen holding charge in the indoor and outdoor units to atmosphere. Open the valves
(hex drive fully out) using a 5mm Allen key. Connect a vacuum pump to the service ports on the
outdoor unit valves and evacuate the system to 1000 microns (1 Torr) or better and allow to be held
for a minimum of 15 minutes.
2. Replace the caps on the service ports, (torque to 25NM).
TEV LTD,ARMYTAGE ROAD, BRIGHOUSE, WEST YORKSHIRE, HD6 1QF. + 44 (0) 1484 405600 +44 (0) 1484 405620
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