Resident script pump circulation

[Domoticatorino]

Code:

valveStatesTagEstate = 'pompa_circolazione_giorno_estate'
valveStatesTagInverno = 'pompa_circolazione_giorno_inverno'
pumpGA = '2/0/1'
openingValveTime = 60 -- time for fully open the valve (maximum time for next calculation)
minInterval = 30 -- minimum offset for next calculation

opened, firstTimestamp = false, 0

if stagione == false then
    valveStatesEstate = grp.tag(valveStatesTagEstate)
    for v = 1, #valveStatesEstate, 1 do
     valveStateEstate = valveStatesEstate[v]
     if valveStateEstate.value then
       opened = true
       if firstTimestamp > 0 then
         if firstTimestamp > valveStateEstate.updatetime then firstTimestamp = valveStateEstate.updatetime end
       else
         firstTimestamp = valveStateEstate.updatetime
       end
     end
 end
else
   valveStatesInverno = grp.tag(valveStatesTagInverno)
   for v = 1, #valveStatesInverno, 1 do
     valveStateInverno = valveStatesInverno[v]
     if valveStateInverno.value then
       opened = true
       if firstTimestamp > 0 then
         if firstTimestamp > valveStateInverno.updatetime then firstTimestamp = valveStateInverno.updatetime end
       else
         firstTimestamp = valveStateInverno.updatetime
       end
     end
end
end

if opened then
   fullyOpened = (os.microtime() - firstTimestamp) >= openingValveTime
   if fullyOpened then
       grp.checkwrite(pumpGA, true)
       nextCalculationAfter = minInterval
   else
       grp.checkwrite(pumpGA, false)
       nextCalculationAfter = openingValveTime + 1 - (os.microtime() - firstTimestamp) -- run a little after possible change
   end
else
   grp.checkwrite(pumpGA, false)
   nextCalculationAfter = openingValveTime + 1
end

-- log('Next calculation after: ' .. nextCalculationAfter .. 's.')
log(valveStatesEstate)
os.sleep(nextCalculationAfter)

Hi,
In your opinion what is wrong in this script above. I add a condition to separate winter condition from summer condition.

I log variable log(valveStatesEstate) but the result is nil. Objects tags are correct and in other 2 scripts (the same) everything works fine.

I cannot understand the reason why it does not working. I expect to read TRUE in log (valveStateEstate).

Thank you for your help.