The equipment used today for spraying plural component urethane foam and coatings provide the means to preheat the A and R chemicals, pressurize the chemical to the manufacturer’s recommended PSI and deliver that conditioned and heated chemical to the gun via a heated hose. Most units today utilize a system which provides automatic hose heat. The proportioners are equipped with a controller which receives a signal from a temperature sensing unit. The signal indicates the temperature of the chemical in the hose from a remote distance from the proportioner and ideally just before the gun.
These sensing units are better known as TSU, FTS or RTD. These sensing units are installed on the hose and in most cases are very close to the gun. Since the hoses are dragged over obstacles, dropped and go through rough use, the sensing units will break and must be replaced. Some equipment manufacturers provide a sensing unit that is one piece and requires that all the hoses be disconnected to replace the unit. This is time consuming, costly and messy. PMC offers a Slim Line TSU housing that allows for the thermocouple to be replaced WITHOUT removing the hoses. When replacing a PMC thermocouple it is recommended that you place the TSU on a bucket as shown below, which will prevent chemical from leaking on the floor.
- Bleed down the pressure on your system
- Unplug the TC or RTD harness
- Remove the old Thermocouple and insert a replacement
- Tighten the fitting, reconnect the harness, bleed the system and you are ready to spray.