Cleaning strainer (M, Fig. 9)

1. Set the switch marked HEATER CONTROL to OFF (Fig. 5). Allow the circulation pump and the auxiliary pumps (HC heater only) to continue operating for approximately 5 minutes.

2. Set the switch labeled CIRC. PUMP to OFF.

3. For HC heaters, set all switches labeled AUX. PUMP to OFF.

4. Set valves as indicated in Fig. 3 for Clean Strainer. (See also Fig. 4.)

5. Place a bucket or other container under the drain valve (Fig. 6). Container should be at least 5-gallon capacity.

   NOTE: Wear chemical and heat resistant gloves as shown in Fig. 6.

   

   
   Figure 6. Drain valve installed in strainer flange.
   (Wear chemical and heat resistant gloves as protection from hot oil.)

6. Open drain valve to drain thermal fluid from the strainer. Do not re-use this fluid. Dispose of it properly.

7. Unbolt the square flange from the bottom of the strainer. Remove the flange, and the strainer basket will slide out.

8. Clean the strainer basket with fuel oil, then dry completely with compressed air.

9. Re-install the strainer basket and flange.

10. Close drain valve.

11. Install a cap on the drain valve (Fig. 6) to protect against accidental release of thermal fluid.

Bleeding air from the circulating pump
(P, Fig. 9)

1. Make sure that the HEATER CONTROL switch (Fig. 5) is set to OFF.

2. Close the valve number 4 (N, Fig.9) in the thermal fluid line at the helical coil inlet.

3. Observe coil inlet pressure gauge (Fig. 8). When gauge indicates normal operating pressure, open valve fully at inlet of helical coil. Normal operating pressures are shown in Fig. 7.

4. Repeat as necessary until pressure indication is steady at its normal pressure.

Figure 8. Left: Outlet pressure gauge. Right: Inlet pressure gauge.