fiac TDRY 6-18 Manuel D'instructions page 53

Traces of humidity and slag which could accumulate inside the chilling plant, or smudge which could occur
after a long use of the dryer, could limit the lubrication of the compressor and clog the capillary tube. The
function of the dehydration filter, located before the capillary tubing, is to stop the impurities, so avoiding
their circulation within the system.
It consists of a piece of reduced cross section copper tubing located between the condenser and the
evaporator to form a throttling against the flow of the refrigerating fluid. This throttling creates a pressure
drop, which is a function of the temperature to be reached within the evaporator: the lower the capillary tube
outlet pressure, the lower the evaporation temperature. The length and the diameter of the capillary tubing
are accurately sized with the performance to be reached by the dryer; no maintenance/adjustment
operations are necessary.
The air-to-air and the air-to-refrigerant heat exchangers plus the demister type condensate separator are
housed in a unique module.
The counter-flows of compressed air in the air-to-air heat exchanger ensure maximum heat transfer. The large
cross section of flow channels within the heat exchanger module leads to low velocities and reduced power
requirements. The air-to-refrigerant exchanger, with counter-current flows, assure excellent performances.
The generous dimensions of the exchange surface determines the correct and complete evaporation of the
refrigerant (preventing liquid returning to the compressor). The high efficiency condensate separator is located
within the drying module. No maintenance is required and it offers the additional advantage of creating a cold
coalescing effect for excellent air drying results. The generous collection volume assures the correct operation
of the dryer even with extremely damp inlet air.
This valve injects part of the hot gas (taken from the discharge side of the compressor) in the pipe between
the evaporator and the suction side of the compressor, keeping the evaporation temperature/pressure
constant at approx. +2 °C. This injection prevents the formation of ice inside the dryer evaporator at every
load condition.
ADJUSTMENT
The hot gas by-pass valve is adjusted during the manufacturing testing
phase. As a rule no adjustment is required; anyway if it is necessary
the operation must be carried out by an experienced refrigeration
engineer.
WARNING : the use of ¼" Schrader service valves must be
justified by a real malfunction of the refrigeration system. Each
time a pressure gauge is connected, a part of refrigerant is
exhausted.
Without compressed air flow through the dryer, rotate the adjusting
screw (position A on the drawing) until the following value is reached:
Hot gas setting (R134.a) : temperature 0.5 °C (+0.5 / -0 °K)
Hot gas setting (R404A) : temperature 0.5 °C (+0.5 / -0 °K)
5.9 DEHYDRATION FILTER
5.10 CAPILLARY TUBE
5.11 ALU-DRY MODULE
5.12 HOT GAS BY-PASS VALVE
pressure 2.0 barg (+0.1 / -0 bar)
pressure 5.2 barg (+0.1 / -0 bar)
GB
TDRY 6-32
A
4 mm
5/32 in.
-
+
TDRY 12-18 Silver
TDR 49-168
A
4 mm
5/32 in.
-
+