(preliminary) fix @ (bed) preHeatError

Firmware/temperature.cpp

@@ -1174,7 +1174,7 @@ void temp_runaway_check(int _heater_id, float _target_temperature, float _curren
 				SERIAL_ECHOPGM(" Tstart:");
 				MYSERIAL.print(__preheat_start[_heater_id]);*/
 				
-				if (_current_temperature - __preheat_start[_heater_id] < 2) {
+				if (_current_temperature - __preheat_start[_heater_id] < ((_isbed &&(_current_temperature>105.0))?0.6:2.0)) {
 					__preheat_errors[_heater_id]++;
 					/*SERIAL_ECHOPGM(" Preheat errors:");
 					MYSERIAL.println(__preheat_errors[_heater_id]);*/
@@ -1184,7 +1184,7 @@ void temp_runaway_check(int _heater_id, float _target_temperature, float _curren
 					__preheat_errors[_heater_id] = 0;
 				}
 
-				if (__preheat_errors[_heater_id] > ((_isbed) ? 2 : 5)) 
+				if (__preheat_errors[_heater_id] > ((_isbed) ? 3 : 5)) 
 				{
 					if (farm_mode) { prusa_statistics(0); }
 					temp_runaway_stop(true, _isbed);