How to determine if A/C unit is low on freon

[brboot]

Hi,
We have two Lennox 13 seer a/c units that are a little over a year old. Last year we had an issue where the upstairs unit wasn't cooling properly when it became relatively hot outside. We called and both units were a couple of pound low! We didn't realize the lower unit was low as it seemed to cool ok. Before we moved into the house one of the units had to be filled(it's still not clear which one). My question is I've noticed the upstairs unit has water pouring out of the condenstation line. Much more than the lower unit. The humidity is around 43 percent both upstairs and downstairs so they are the same. Is this a sign that it's getting low on freon or is it just because the upstairs unit is larger?

Thanks!

[gary_g]

Having the tech check "superheat" and "subcooling" is the best way to determine if the system is low on refrigerant, or if it is over-charged.

Take care.

[BaldLoonie]

Heat & humidity rise. So could be that the upstairs has more of a load on it so is putting out more moisture.

Gary is right, only a good tech checking out all the readings can tell you for sure.

If you've added in the past without the leak being fixed, well could be low!

[crzymtrbiker]

So like the guys said only a good technician will be able to say whether or not the unit is low in charge. The real Question I would ask is why the technician would add more charge for no reason...If this happens on a consistent basis the unit is leaking and should be checked for it....My suggestion is that you ask the company that installed if they did not get everything set when it was installed. This can happen sometimes and they need to come back to perform a courtesy call you get you up to par. If they are charging you $$$$ then you there is definitely a problem with that company being fair with their Job workmanship

[brboot]

Thanks for the great advice. The issue is I called them a few months back to do a "courtesy call" to give the systems a good check since freon has been added in the past and the reply was they would charge me for the call if they indeed weren't low. They did tell me if it stops cooling to call them and they would come out for free. I really don't want to get to that point if there is a problem.

[Cool_Air]

Having the tech check "superheat" and "subcooling" is the best way to determine if the system is low on refrigerant, or if it is over-charged.

Take care.

Superheat or subcool plus the right air flow is a must!!!!!!!

[udarrell]

Superheat or subcool plus the right air flow is a must!!!!!!!

Right-On Cool_Air.
Always get the air flow checked & correct first, before checking the charge!

If the duct system has never been thoroughly examined, that is an absolute requirement.

A very high percentage of duct systems have air leaks & may not be properly insulated, & do not have the proper airflow.