Some reciprocating open-type compressors used with water cooled systems incorporate a cylinder head cooling feature in the form of a water circuit through the compressor head. Supply water enters this before entering the condenser (see Figure 16). A rapid indicating thermometer is recommended for taking water temper- atures because the water regulating valve responds to the operating head pressure and will vary the temperature of the water as it modulates. It is also necessary, when adjusting the water regulator, to be able to take inlet and outlet temperatures quickly. Locate the thermometer probes tightly to the pipework to ensure good thermal conductivity, note the average inlet temper- ature and calculate.
