Advice to cool up stairs

lmbgm

I have a 3 story townhouse (about 1800 sqft). I've got a York 3.5 ton AC.

On the 2nd and 3rd floor it often gets too warm in the afternoon when the sun beats down in my living room. The thermostat is on the second floor in the main living room. For example, if it is 73 outside and I set the AC to 77, it might only be able to cool down to 79. I measure the temp coming out of the vents on the 2nd floor and they are only around 72. If I stick my prob in right next to the evaporator on the first floor, its around 58. I also tried closing all the vents in the house except for the ones in my living room but it doesnt seem to make any difference. The system was tested in november and certified to be ok (when I bought the house. Before I make another call and pay for an HVAC guy to come out, are there any simple things I might be forgetting? I've tried replacing the Air filter, cleaning the condenser fins. It may be my imagination, but I don't seem to remember having this problem earlier in the summer and the temperature is about the same.

beenthere

Indoor coil may be dirty, and restricting air flow.

lmbgm

thanks I'll take a look. The humidifier is pretty close to it so I can get access to it.

Actually, now that I think of it, I added the humidifer over the winter, the only place it would fit is right next to the evaporator. maybe that extra moisture right next to the coil clogged it

beenthere

The dirt would be on the under side of the coil.

Is it a bypass humidifier? If so, did you close the bypass damper this spring/summer. if not, then you are decreasing your air flow.

Also, make sure that the humidifier can't run during the summer. or you won't cool the house.

lmbgm

no it is not a bypass, it is powered, did not have enough space. Yes it is off.
I tried turning it on the AC and I could not feel air going through, seems to be going around it.

I'll try some coil cleaner and see what that does for me.

Thanks

kenmac

If you've never had a problem with it cooling.. You must have a problem..

lmbgm

yes there are returns on every floor.

I assume I should be feeling air coming out of the fins on the evaporator coil. since I am not, I assume the first replier was correct and my coil is clogged.

I tried looking for coil cleaner at home depot and lowes but neither had any.

Are there any kitchen cleaners that are equivalent? can I just hose it down with water? I dont want a bunch of water getting into the motor

beenthere

Depends how dirty the coil is.

Often. The dirt needs to be brushed, or combed from teh underside of the coil first, when they get to bad/dirty.

Simple green works well in many cases.

delstu

First, make sure the filter is in good condition and clean.

Have you checked the other side of the coil yet? They are usually blocked by debris matted on the side air-flow blows into. This mat is usually easy to remove with a brush. Get one corner loose and the entire mat may pull off easily.

Sometimes it is not as easy to remove if someone in the house is using hairspray or anything sticky. Then you might need a liquid cleaner to soften the dried hairspray.

Attempting to clean the coil from the wrong side could cause the problem to get worse.

Make sure you always keep a filter in the system to help minimize these problems.

lmbgm

how do I get access to see the other side of the coil? the sides arent open. Do I have to remove the entire coil? If so, I will probably need to call a pro.

Which is the correct side to spray the cleaner?

beenthere

The end plate can be removed. But, it is risky. You could cause a leak in the lines.

Often, you can see just enough under the drain pan to see if the coil is dirty.

OldSingy

Some questions:

1. Is this a new problem or has it gotten worse over time?
2. Is the furnace/air handler blower running at the correct speed in A/C mode?
3. Is the filter clean? Is the filter correct for the application? Some filters can cause large pressure drops and air restriction.
4. You said your humidifier is ok, so I'll skip that.
5. Is the blower direct drive or belt-driven? If belt drive, is the belt tight and not slipping?
6. When was the last time the blower wheel was cleaned? Even 1/16" of dirt on the fan blades can cause a 20% drop in fan efficiency.
7. Do you have an attic fan and is it working ok? Is the attic adequately vented? (If no attic, disregard)
8. Is your A/C unit operating correctly? Is the charge ok, the condenser coil clean, correctly sized, etc?
9. How's your attic or roof insulation?
10. How's the ductwork? Is it clean? Are there joint leaks?
11. Is the system reasonably balanced?
12. Finally, if you know how to use a manometer, you can measure the air pressure drop across the indoor evaporator coil. If it's more than 1", then the evaporator should be cleaned. (the filter MUST be clean before you perform this test, and the blower MUST be operating properly)

AllanJ

While you can close off a few vents to direct more cold air to other ducts, do not close off too many ducts. Othewise the total air flow will be reduced too much and the AC coil can freeze up.

__________________
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lmbgm

well, I tried the spray cleaner, it seems to have helped a tiny bit, I can feel a tiny bit of airflow through the evaporator. So I think I'll need to call a pro.

beenthere

It probably has a blanket of dirt on the inlet side of the coil. Often, you need to remove that by comb or vacuum first.

So if your coil is hard to access. You may indeed need a pro to pull the coil.