Walton pneumatically operated valves may be installed as either flow diverting or mixing valves, although the latter is recommended.

When installed as a diverting valve and at temperatures below the set temperature, the rotor directs all the fluid to bypass the cooler, while above the set temperature all the fluid is directed through the cooler. During normal operation the flow is automatically proportioned between the bypass and cooler to maintain the incoming fluid at the set temperature.

When operating in mixing mode, the valve is installed downstream of the cooler.  The hot and cold fluid streams enter the valve in a proportion determined by the position of the rotor.  The temperature of the fluid leaving the valve is maintained at the set temperature.

The valve may be installed in any attitude, gravity having no effect on its operation.

The operation of the system requires that the Walton controller periodically samples and compares the temperature in the coolant system with the predetermined set temperature and if necessary adjust the position of the rotor within the valve by means of an electrically driven actuator.  The time interval between samples is variable, but to achieve stable control within the system should be as long as possible.  It should never be less than the system interval which is the time taken for ‘a given volume of fluid’ to complete the circuit of the system.

The resistance thermometer generating the operating signal is installed in the system at the point where control of the fluid temperature is required.

The system pipework should be as simple and compact as possible.  The cooler by-pass pipe should be designed for minimal pressure loss.  The pressure difference across the 3-way valve at full flow through either the cooler or cooler bypass should not exceed 0.8 bars.

A degree of flexibility in at least one of the connecting pipes is desirable although, if care is taken on installation, not essential.  Mounting of the valve should be such that it is not subjected to excessive loading or vibration under running conditions.

For marine applications, temperature variations, pipe expansion and movement of the ship's hull should be taken into account when designing the piping runs and supports.