A few things that show up if you turn on all the compiler warnings:
Line 14 - not an error, but [12] is needlessly long, 5 is sufficient to allow for terminating null and á which is not standard ascii
char daysOfTheWeek[7][12] = {"Dom", "Seg", "Ter", "Qua", "Qui", "Sex", "Sáb"};
Line 129: collectorsEmpty is already declared as a global variable of type boolean, you are declaring again in setup()
also, in the rest of the code you set its value, and do comparisons, using 0 and 1 instead of true/false.
Will work, but confusing.
byte collectorsEmpty = 0;
Line 163: calculation is done as integer, exceeds maximum value of integer.
Change the 24 to either (long)24 or 24l to force equation to use a long.
if (chronoCloudTimeSet.elapsed() >= (24 * 60 * 60 * pow(10, 3)))
Line 202: sensorTInterval should be unsigned int to match the type of the number it is being compared to later
not really a problem, I just don't like seeing the compiler warning
int sensorTInterval = 5e3;
Line 446: Statement does nothing, comment it out
emergencyHeatingStatusON; //minutes that emergencyHeatingStatus has been on, since the last cloudWriteInterval
Line 450, 451, 453 - same as above
overheatStatusOn; //minutes that overheatStatus was on, since the last cloudWriteInterval
maintenanceStatusOn; //minutes that maintenanceStatus was on, since the last cloudWriteInterval
solarKWH; //when timeStopCoil, store measurement sensorT1Value. when timeStartCoilHour, store measurement sensorT1Value. Subtract 1 from other.
Starting at Line 494
Last line, you have a global variable solarKWH, by declaring it again here you are throwing away the result.
sHWater and heatAdded should be declared as float, using byte will only save the whole number, the fractional part gets dropped.
//calculated, archived, and reset every 5 minutes?
void energyInflux()
{
//Specific Heat is the amount of energy required per unit mass to raise it one degree Celsius.
//The specific heat of water is known. It is 1 calorie/gram °C = 4.186 joule/gram °C
byte sHWater = 4.186;
//Q(heatAdded)=c(specific heat)*m(mass)*deltaT(temperature difference)
byte heatAdded = (sHWater * (totalSessionFlow / 1000) * deltaT); //
byte solarKWH = (heatAdded / (3.6 * pow(10, 6)));
}