10.14 Heater Circuit
The water temperature in the pressure tank is controlled by a thermistor probe. The
thermistor has a variable resistance; when cold it has a high resistance and when hot
it has a low resistance.
1.
The thermistor probe sits directly in the water and continuously senses the water
temperature. The resistance of the thermistor is interpreted by the controller
as a temperature reading.
Note: The resistance of the thermistor when at ambient (room) temperature
should measure about 3000 ohms, when hot (205°F/96°C) it should measure
approximately 220 ohms.
2.
If the water needs to be heated, a signal from the controller is sent down the
Comms. link to the I/O board (heater on signal). The I/O board then switches a
24 volt negative output to the solid state relay. The solid state relay then switches
a 115V supply to the heater element. The element then starts to heat up the
water.
Note: Heating element fitted in the pressure tank is rated at 1250W.
82
Technical Manual
PRESSURE BOILER
MAIN CONTROLLER
BOARD
SOLID
STATE
RELAY
1.25kW HEATER
N
Summary of Contents for Espresso B2C
Page 2: ......
Page 98: ...Exterior View 96 Technical Manual 2 4 5 7 8 6 10 9 11 15 14 3 12 13 1 ...
Page 100: ...Door Interior 98 Technical Manual 1 2 3 4 5 6 2 7 8 9 10 11 12 13 14 16 15 17 18 ...
Page 102: ...Console Assembly 100 Technical Manual 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ...
Page 104: ...Interior View 102 Technical Manual 1 2 3 5 4 6 7 15 11 12 13 8 9 10 14 16 ...
Page 110: ...Ingredient Canister Assembly 108 Technical Manual 1 11 8 4 9 10 7 6 3 2 4 5 ...
Page 112: ...Freshbrew Canister Assembly 110 Technical Manual 6 1 4 7 8 9 3 2 4 5 ...
Page 114: ...Dispense Head Assembly 112 Technical Manual 1 2 3 4 5 6 7 8 9 10 ...
Page 116: ...Mixing System 114 Technical Manual 1 2 3 4 5 6 7 8 9 ...
Page 118: ...Power Supply Assembly 116 Technical Manual 1 2 3 4 5 7 7 7 6 ...
Page 120: ...CoEx Brewer Motor Assembly 118 Technical Manual 2 4 1 3 5 7 6 8 9 ...
Page 122: ...Water Inlet Pressure Valve Assembly 120 Technical Manual 3 2 1 4 5 ...
Page 124: ...Pressure Boiler Assembly 122 Technical Manual 2 6 3 4 1 7 5 6 ...
Page 126: ...Fresh Beans Container 124 Technical Manual 1 2 4 3 ...
Page 129: ......
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