Hot Topics: Is This AC Unit Done For? Hot Topics: Is This AC Unit Done For?

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Not sure if your AC unit has much life left in it? Check out this topic to see the warning signs.

Original Post: Is My Central Ac Running on Borrowed Time?

MiamiCuse Member

My AC bill is shooting through the roof. For the month of July it was $250 and it's only a 2 bed 1 bath 800 SF place. Compared to last year it is almost double.

The AC company came out and checked it out, the temperature differential is 16 degrees at the closest vent. When it's 98 degrees out, it's only going to cool to 82 and no more. If I set it to 78 it will run all day and hence the high electric bill.

The A/C company said basically the unit is cooling but it is "living on borrowed time". The evaporator coil is in rough shape and flaking apart, and the head pressure is 400PSI which he said is very high and the reason my electric bill is so high and it can fail at any time.

So the recommendation is to install a new system ASAP, there is no repair or tweaking he could do to make it cool better or more energy efficient.

Verdict? Replace it now or wait for it's sudden death?

Highlights from the Thread

Pulpo Member

There is no guarantee that a new unit is going to reduce your bill. Even if it does, how long will it take you to recover your money?

Muggle Member

14 years is not old for an a/c and high head pressure is not caused by normal wear and tear, but rather total neglect of the outdoor unit, a metering device problem or restriction.

The temperature difference needs to be measured at the air handler and not a vent, especially if the ducts are in the attic.

One thing you can do yourself is feel the uninsulated copper line at the outdoor unit - it should be warm, not hot. The condenser coil should be thoroughly cleaned.

Also feel the same line at the air handler, it should be about the same temperature there, if it's significantly cooler, this line may be very badly kinked causing a restriction and high head.

That's the limit of what you can check yourself.

HVAC RETIRED Member

A higher seer rating does not necessarily mean increased savings on your monthly utility bill, if you have real high humidity conditions to deal with 'sometimes' a 10 seer unit will bring down the humidity and then the sensible temperature on the thermostat a lot faster than a 13 seer unit and therefore will end up with less run-time and be as efficient as the 13 seer unit.

This idea that a higher seer unit is going to be more efficient under all conditions is somewhat of a fantasy.

If the condensing unit is in good shape fins and everything, it may be partially plugged with Cottonwood if you have Cottonwood trees nearby it will plug the condenser coil, or there may be other debris in the condenser coil, additionally, the fan motor may not be up to speed in may not be pushing enough CFM through the condenser coil; test the run capacitor, etc. It also appears there may be a restriction in the refrigerant system.

MiamiCuse Member

Here are a few pictures. First a pic of the entire unit.

With the cover removed, the capacitor.

The coil up close.

Houston204 Forum Topic Moderator

The condenser coil looks bad to me. A closer shot of the fins of the coil would help.

Do you get aluminum flaking off of the outdoor coil when you rinse it? (With the service disconnect off)

Do you see any sections of the outdoor coil that the fins have fallen off of?

Read more at: //www.doityourself.com/forum/air-conditioning-cooling-systems/553750-my-central-ac-running-borrowed-time.html

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