MAHLE RTI RRC750X - Manual (Page 12)

Refrigerant Technologies, Inc.
May 24, 1993 Page 11
HIGH PRESSURE SWITCH
The High Pressure Switch opens-on-rise at a pressure of 261 ± 7 PSIG and closes on-fall at 203 ±
7 PSIG. The Compressor turns off and Solenoid Valve S11 closes to prevent flow of refrigerant
through the system.
OIL SEPARATOR
Filtering of the refrigerant to remove oil is accomplished by a fine composition filter element.
Refrigerant enters through the top of the canister to the inside of the element, passes through the
element towards the outside, and then exits from the bottom of the canister.
The removal of oil is important to prevent clogging the Filter-Drier which removes moisture from
the refrigerant.
CHECK VALVE (5 PSI)
The Check Valve permits forward refrigerant flow when pressure from the outlet of the Oil Separator
is 5 lbs. or more than the outlet pressure of the Check Valve.
FILTER BY-PASS VALVE
Manual operation of 3-way Filter By-Pass Valve facilitates purging refrigerant from the filters prior
to their removal. Operation of this valve is described in the Maintenance Section of this manual.
FILTER-DRIER
Refrigerant enters the top of the canister and flows through a perforated plate and then through
moisture absorbing desiccant. Moisture removal is very important due to the formation of acids
which result when water and refrigerant are allowed to mix.
The Filter-Drier must be changed after every 75 hours of operation.
CONDENSER (COOLED BY FAN)
The high temperature, high pressure refrigerant vapor is cooled by air moving over the finned
Condenser. The vapor condenses into liquid form as it is cooled.
EXTERNAL CYLINDER
Refrigerant flows to the External Cylinder until the weight switch shuts the RR750X off due to a full
cylinder.
DIFFERENTIAL PRESSURE SWITCH (DPS)
The venting of non-condensable gases (Air) is performed by the DPS Assembly. A refrigerant/Air
mixture will exhibit a higher pressure than pure refrigerant. Pressure inside a sealed bulb of pure
refrigerant is compared to the refrigerant/Air mixture at the External Cylinder at equal temperatures.
When the Air concentration in the Internal Cylinder reaches a preset amount, the DPS activates the
Non-condensable Gas Discharge Solenoid (S8). The Air is slowly vented until the pressures again
equalize.