The service port has a schraeder valve in it which easy to replace, the problem is, to replace it you have to empty the gas from the system before you can unscrew it. The service port should have a plastic dust cap on it which is also a secondary seal, this is enough to stop a slight leak past the valve, so just check it's tight and the get the valve replaced the next time it needs re-gassing.
And in answer to your earlier question of how cold it should be, with an ambient air temperature of 20-22c it should be about 5c at the centre vents with the blower fan at half speed and if everything is working as it should be.
And in answer to your earlier question of how cold it should be, with an ambient air temperature of 20-22c it should be about 5c at the centre vents with the blower fan at half speed and if everything is working as it should be.
