Air Conditioner outlet temp is very slow to drop

[Div Grad]

I have an air-con system about three years old that I have not had any complaint with. However this year I noticed that the unit runs for extremely long periods.

Today I noticed the unit was running long and I put a thermometer in a vent to measure the temperature drop. What I discovered is that it is taking something like an hour to for the outlet temp to fall to 20 degrees below room temp. What is that an indicator of?

I can provide more info in necessary but am hoping the facts above already point to one likely cause. Outside temp was about 25, inside temp about 24, and I wanted to drop inside temp to 22. Took about an hour or more for outlet temp to drop to 14.

[2old2rock]

If your system was working well, and now it's not working well, you should call a service company. Unless you have not changed your filter in a while.
We can't solve your problems over the net.
Well, maybe we could, but we're not allowed to here.

[martyinlincoln]

More then likely just needs a good service. Doesn't cost much so don't be scared to call.

[wptski]

More then likely just needs a good service. Doesn't cost much so don't be scared to call.
Just needs a good service. Explain just what that involves.

[BaldLoonie]

How humid was it? If you let humidity build up inside, first hour(s) of run time temp changes little, the A/C is removing latent heat which is humidity. Once that is down, temp drops.

Outlet temp doesn't mean a lot either. Key is temp drop over the coil. And back to humidity, while a unit is sucking out the moisture, temp drop is less.

[RayD8630]

This is true and I noticed the past few days where I am have been very humid. I see you're posting in Celsius. Are you in Canada and if so where about?

[martyinlincoln]

Just needs a good service. Explain just what that involves.

Sorry Bill but I know instructions on how to service AC's are not allowed on this forum

[udarrell]

How humid was it? If you let humidity build up inside, first hour(s) of run time temp changes little, the A/C is removing latent heat which is humidity. Once that is down, temp drops.

Outlet temp doesn't mean a lot either. Key is temp drop over the coil. And back to humidity, while a unit is sucking out the moisture, temp drop is less.
Pay attention to Baldloonie.

Go to a hardware store & get a humidity gauge, everyone should have one.

What SEER is the condenser & what is its discharge air-temp split to outdoor temp? That will indicate if it has a heavy latent load on the evaporator.

You also need to know that the CFM airflow is correct. :pop:

[Div Grad]

I never thought about the humidity aspect, thanks for the tip. The day I did monitor was one where the system had been off for a few days and this was the first power on, so I guess that that could mean it was dealing with maximum humidity and had to take that down first.

Would that then mean that the first run could be long but then to maintain the temp I could expect to see the 20 degree drop much sooner since humidity was dealt with in the first run?

Anyways, I think I'll put in for a check up on the system.

And yes, I am in Canada. In Toronto where it is stinking hot and humid. We've been having many days recently where the humidex is over 40 degrees C (about 105 F).

[RayD8630]

Yeah that would make a lot of work for the unit I'd say.

[udarrell]

This could yield helpful information concerning a units latent performance, but is not telling anyone how to fix anything.

This is for anyone that wants to ballpark check the latent BTUH your A/C is performing at, - under differing indoor humidity level conditions.

http://www.udarrell.com/latent_heat_condensation.html

There are, of course, ways to figure what the unit should be condensing at specific indoor conditions. If it is much off target, the Tech needs to find the cause(s) & eliminate them.

Let me know if you find any gross errors, I'm human...