Table of Contents
Advertisement
Technical Manual
11.21 Heater Circuit - LINEA
The water temperatures in the Gravity Boiler and the Pressure Boiler (Espresso machines)
are controlled by NTC thermistor probes. They have a variable resistance - high resistance
when cold, low resistance when hot. The thermistor probe is in contact with the water and
continually monitor the water temperature. At room ambient temperature the thermistor
resistance is approx. 3000 ohms. At 205°F the thermistor resistance is approx. 200 ohms.
Both Boiler Heating Elements are controlled by a Solid-State Relay which are in turn con-
trolled from the I/O Board. The Gravity Boiler Element is rated at 1.2kW, and the Espresso
Boiler Element is rated at 1.0kW.
Should control of the Heating Elements fail for any reason, both Elements are protected by
inline resettable Thermal Cut-Outs. These are positioned in the overflow pipe of the Gravity
Boiler (176°F), and on the casing of the Espresso Boiler (244°F).
155
Advertisement
Table of Contents
