Air Conditioning Problem

[682bear]

My central A/C system quit today...

The compressor is running, the thermostat is working, when I turn the temperature down, it clicks like it is turning the blower on... but the blower doesn't run.

The pipe that goes from the air handler in the basement to the outdoor unit had ice on it... from what I'm reading, that can mean low freon? But wouldn't the blower still run even if the freon is low?

I have a repair guy coming out tomorrow... I'm sure he will tell me I need to replace the entire system, but if A/C systems are like appliances, the new ones cost three times as much and last ⅓ as long, so I'd really like to squeeze as many years as possible out of this one.

It's a Trane system... it was installed in 1999, and the compresser was replaced in 2015.

Any advice or information is appreciated...

-Bear

 

[pontiac428]

Here's my guess (I'm an expert at guessing):

Condensate line plugged means ice on the expander coils, most likely. Possible you even froze the blower, might be worth checking on before firing it back up to make sure it's clean and dry. Freon loss means everything gets hot and your pump dies, but it is not common for a system to work one day and not the next without physical damage. Typically it happens over time.

A good HVAC shop will offer you options, but central AC is by and large a 10-year system at best. New units are getting quieter and more efficient. My unit is on it's 3rd year and doing great, but the primo warranty is halfway up. Had it serviced this year and had a bit of cat hair in the condensate tray. Glad they got it, because the coils were starting to ice... Easy fix, system blows cold as ever now.

 

[markba633csi]

Sounds like the blower motor is not getting power- thermostat fault?
OR maybe a problem with the blower motor itself-?

 

[Ischgl99]

The four things I would check, make sure you have voltage to the blower motor, there could be a problem with the contactor, it could be a bad motor as Mark said, capacitors do not last forever on these, so that should be checked, and last, the controller itself. The AHU blower motor failed last summer, but I have also had the blower motor fail in the AC unit, that was a while ago, but I believe that was a failed capacitor, those are fairly cheap and easy to replace if you do that yourself. I’ve also had an output on my control board fail and needed to replace the entire controller, that was a fairly simple fix, just took a few days to get the new controller.

 

[woodchucker]

Here's my guess (I'm an expert at guessing):

Condensate line plugged means ice on the expander coils, most likely. Possible you even froze the blower, might be worth checking on before firing it back up to make sure it's clean and dry. Freon loss means everything gets hot and your pump dies, but it is not common for a system to work one day and not the next without physical damage. Typically it happens over time.

A good HVAC shop will offer you options, but central AC is by and large a 10-year system at best. New units are getting quieter and more efficient. My unit is on it's 3rd year and doing great, but the primo warranty is halfway up. Had it serviced this year and had a bit of cat hair in the condensate tray. Glad they got it, because the coils were starting to ice... Easy fix, system blows cold as ever now.

My Bryant A/C is circa 1987 and still going.

 

[pontiac428]

My Bryant A/C is circa 1987 and still going.

And when you replace it, you will be surprised that the new unit fits in a flat rate box.
Your Frigidaire is probably still running if you've got one of those.

I just mean that new appliances have shorter lifespans. Washer/dryer is engineered for 3 years, some of us get 6... I do after replacing the rollers and supports and cleaning out the heat exchanger. I don't play an AC tech on TV, so I'm worse than a pretender- I have the passive privilege of living next door to a HVAC company. But the talk across the fence over the years, and seeing what the trucks drag back in, they operate on the principle that central air is a 5-7 year appliance. Those are the same kind of years that apply to my washer and dryer, so YMMV, but from an industry point of view, you should be replacing appliances more often than you want to. They build the clock, so they set the alarm as they see fit.

 

[rabler]

Pretty much what @ischg99 said:
Yes, *I think* the blower would run even if the freon was low.
If something is wrong with your blower motor (including the control circuit, contactor, capacitor, etc), it would be easy for the compressor to run and cause the lines to ice up since there is not effective heat exchange but constant demand on the compressor. I'd start by putting a volt meter on the blower motor to see if it is getting power while the system was running.

 

[682bear]

I agree that the problem seems to be either the blower motor or in the circuit that controls the motor... maybe a relay?

I'm hoping it is something simple... and that I can get a few more years out of this system...

We'll see what the repairman says tomorrow.

-Bear

 

[Nutfarmer]

Check the capacitor for the blower. Simple check. I don’t know what is going on with the new capacitors now days, but 80 percent of the time the ac goes down in one of the rentals it’s a cap.

 

[PNW_Guy]

Clearly the pilot light is out.

Not saying you should replace it, but newer units are worth looking at. Much more efficient, and there are tax incentives to consider.

My folks replaced their 20 year old "high efficiency" heat pump with a mini split. The old unit ran on 3 breakers, with a total of over 100 amps. Mostly due to resistive heating required below 45. The new unit runs on 25 amps total.

I'm almost done building my house, and I have a 3 head (1 outdoor unit) mini split running on a 25 amp circuit. The weather here goes as low as 20 and as high as 115 - and the house is always 70. Everything but the stove is electric, and my bill has been over $100 once - when we had a month of 20* nights and 35 highs. That one cost me $115.