Antunes, AJ MS-150/155 owner manual Technical Theory of Operation

Technical Theory of Operation

When the Rocker Switch (power On/Off) is ON, line voltage flows to the primary side of the step down transformer. The transformer’s secondary side supplies 12 and 24 VAC to the Control Board.

Once powered, and provided that the Generator tem- perature is below 380° F (193° C), the Control Board calls for heat by supplying 10 - 15 VDC to the Solid State Relay terminals 3(+) 4(-). Once powered, the Solid State Relay closes terminals 1 and 2 which allows line voltage to flow to the Generator.

As the Generator begins to heat up, a type “K” thermo- couple monitors the internal Generator temperature. As the heat continues to increase, so does the thermocou- ple’s DC millivolts. Once the Generator’s temperature rises to 380-420° F (193 - 215° C), the thermocouple is generating approximately 7.5 - 9.0 DC millivolts.

The Control Board receives these millivolts and pro- ceeds to remove the 10 - 15 VDC to the Solid State Relay since the heating circuit has now become sat- isfied. Then, relay terminals 1 and 2 open, and the Generator stops heating.

When the Operate, Single Shot, or Start/Stop button is pressed, the Control Board is signaled to supply 24 VAC to the solenoid valve used in models MS-250/255 or the water pump used in models MS-150/155/355 for a split second.

The solenoid valve opens, or the water pump runs, and allows a shot of water (approximately 25ml or 3-4 table- spoons) to flow onto the generator surface for steam- ing.

NOTE: If the display is in a Timed Cycle (counting down), the Control Board will continue to activate the solenoid valve or water pump for repeated shots of water, once every 20 seconds, and for the duration of the cycle time displayed. See the Programming section of this manual for more infor- mation.

Since the Generator Cover is secured in place with a wing nut, the steam is forced downward through the Generator Steam Ports and onto the product.

The Control Board’s parameters can be custom pro- grammed for the over all cycle steam time (CYC), as well as the interval time in seconds (SHO) when each shot of water occurs, and also the water volume (H2O) used per each shot of water. This Control Board also incorporates several Status Indicator LEDs. See the Operating and Programing sections of this manual).

An audio signal will sound for 3 seconds at the end of a Time Cycle. If the heating circuit continues to call for heat and the Generator overheats, a manual, resettable Hi-Limit Thermostat will trip and open the generator circuit.