M9-4120-370-14
TO35E9-229-1
The refrigerant desiccant dehydrator (filter drier) (D) removes any moisture (water vapor) or dirt that may
be carried by the liquid refrigerant.
The liquid indicator (sight glass) (G) indicates the presence of moisture and quantity of refrigerant in the
system.
The solenoid valve (K3) is controlled by the Temperature control thermostat on the control panel. This
valve will shut off the flow of refrigerant to the evaporator section when the temperature in the conditioned
area reaches the set point.
The expansion valve (V5) controls the amount and pressure of liquid refrigerant to the evaporator coil (E).
The expansion valve (V5) senses the temperature and pressure of the refrigerant as it leaves the evapora-
tor coil. By use of a sensing bulb and "external equalizer line" the valve constantly adjusts the flow of liquid
refrigerant to the evaporator coil (E).
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As the liquid refrigerant leaves the expansion valve (V5) it passes thru a distributor and enters the evapora-
tor coil (E). As the liquid enters the coil at a reduced pressure, the reduction in pressure and the wanner
air being forced across the tubes of the coil cause the refrigerant to boil and change to a gas (vapor). The
evaporator fans circulate the warm air from the conditioned space over and through the evaporator coil.
Refrigerant absorbs heat when it changes from a liquid to a gas. As the air from the conditioned spaces
comes in contact with evaporator coil (E), the air is cooled.
The refrigerant gas is then drawn back to the compressor (B I ) and the cycle is repeated.
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b. Bypass cycle. This unit has a bypass cycle which allows cooling operation at low cooling Ioads without cycling
the compressor (B I ) on and off. In bypass, the refrigerant is piped from the discharge (high side) to the suction
(low side) of the compressor, bypassing the evaporator coil (E).
When the TEMPerature control thermostat on the control panel senses that cooling conditions have
reached the set point, it closes the solenoid valve (K3) to shut off refrigerant flow to the evaporator coil (E).
When the TEMPerature control thermostat on the control panel senses that cooling conditions have
reached the set point, it closes the solenoid valve (K3) to shut off refrigerant flow to the evaporator coil (E).
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As the compressor suction pressure starts to drop, the pressure regulating valve (V2) opens to allow flow
of hot gas from the compressor.
The liquid quench expansion valve (V4) senses the temperature of the gas at the suction side of the com-
pressor. To prevent excessively hot gas from reaching the compressor, the liquid quench expansion valve
(V4) opens to allow liquid refrigerant to mix with the hot gas.
The linear actuating cylinders (L1 and L2 on models F36T4-2S, F36T4-2SA and F36T-2S or single activat-
ing cylinder L1 on models F36T-2SA and F36T4-2SB) automatically control the condenser air discharge
louver assemblies to maintain an adequate discharge pressure.
The service valves (V1 ) are provided for charging, and general servicing of the high and low pressure sides
of the refrigerant system.
The bow pressure switch (S6), the high pressure switch (S5), and the pressure relief valve (V3) are pro-
vided to protect the unit from damage due to pressure extremes.
1-12. HEATING
HI HEAT mode. When the mode selector switch is set for HI HEAT the six heating elements, located in front
a.
of the evaporator coil, are energized. These elements are protected from overheating by a thermal cutout
switch. Three of the elements are thermostatically controlled by the TEMPerature control thermostat, and re-
maining three are on all of the time.
b. LO HEAT mode. When the mode selector switch is set for LO HEAT, only the three thermostatically controlled
heating elements are used.
