The original system used pumps constructed 

 with a split collar integrally cast with the pump housing 

 and clamped directly to a machined boss on the motor. The 

 pump impeller was screwed directly to the armature; 

 however, the large area at the junction of motor and pump 

 housing allowed transfer of motor heat to the water within 

 and the impeller passed an additional amount from the 

 armature. The supply lines thus became filled, alternately, 

 with warm and cold water. The problem was solved by 

 replacing each unit with a separate pump joined to a motor 

 with an insulating coupling, and the entire assembly was 

 shock-mounted on a steel plate. The new motors operate 

 at 3400 rpm which is double their former speed, and they 

 now run continuously instead of starting and stopping with 

 the action of the solenoids. A small manually controlled 

 needle valve (fig, 5) between the solenoid of each external 

 supply and the main tank suffices for maintenance of a 

 given temperature. For large changes, a 1/2-inch, quarter- 



FULL FLOW FILTER 



TAP WATER INLET FROM MAIN 

 RECIRCULATING LINE 

 AIR BLEED VALVES 



HOT TANK 

 HEATING COILS 

 HOT PUMP 



COLD TANK 

 COOLING COILS 

 COLD PUMP 



CALIBRATION TANK 



COLD AND HOT SOLENOID VALVES 

 BALL VALVE BYPASS 



Figure 7. Schematic of circulating system. 



16 



