PID-thermostat: help

[Amelie]

I have a heat pump, which can cool and heat. The switches from Jung measures only the temperature, thus the installer used the PID-function of the logic machine. But now, the heat pump (last week) has changed from heating to cooling. The temperature in the bedrooms was higher than the desired temperature, so one would expect that the valves opened so there was cooling in the bedrooms. But, the valves stayed closed. They went open, when I putted the desired temperature higher than the actual temperature in the room. So, it worked the other way around. 
The script (resident - 10s)  of the installer is:

Code:

Verwarmen = grp.getvalue('1/6/4')  -- status of the heat pump
if Verwarmen then
  Koelen = false
    -- init pid algorithm
    if not p then
      p = PID:init({
        current = '5/2/8', -- actual temperature
        setpoint = '1/4/11', -- desired temperature
        output = '1/4/4',  -- valve
        inverted = false 
      })
    end
-- p:reset()
else
  Koelen = true
    -- init pid algorithm
    if not p then
      p = PID:init({
        current = '5/2/8', -- actual temperature
        setpoint = '1/4/11', -- desired temperature
        output = '1/4/4',  -- valve
        inverted = true 
      })
    end
--  p:reset()
end

-- run algorithm
p:run()

The weird thing is that I save the script (without changing anything), the behavior is normal. Thus, the cooling start as the actual temperature is higher than the desired temperature. But, the heating side works then vice versa.

Can anyone help me wat is wrong?