HVAC problem determination help needed

[wiredgeorge]

If you touch both posts on a capacitor it WILL discharge even when out of the outside unit. Be careful.

 

[lightflyer1]

I had my drain line clog once. I used compressed air to clear it but had to install a valve to close off the pipe that goes to the indoor unit first, as all the air wanted to go to the unit as the downstream pipe was clogged. The valve closes off the AC unit side and only allows air down the drain side. Worked out well with just a little work. Just remember to open it again when done. Same Trane unit. Must have been a popular unit as there were credits available when I bought mine, for high efficiency. I always keep spare caps on hand as I have been down this road several times already. Not good waiting on the AC guy for 2 days in over 100 degree heat. Be careful with the caps though as they can still shock you even when completely freed from the device. They are kind of like a battery with stored energy.

 

[BBL]

Any update? Did you decide to replace the start capacitor? Did you find one locally or order one?

An easy way to tell whether the fan start capacitor is bad is to listen to the fan motor. If it hums, the capacitor is likely bad. You can try to spin the blades (be careful, of course) and if the fan starts, the capacitor is pretty dang likely bad.

If you have a voltmeter or a test light, you can check the voltage on the capacitor. If no voltage on either lug, you have a different problem.
Of course, if you have a 3-lug capacitor, the test process will be different. Let us know.

 

[joking]

If you touch both posts on a capacitor it WILL discharge even when out of the outside unit. Be careful.

And be sure to discharge it once the wires is disconnected.

 

[FireInTheWire]

Tons of YouTube videos on capacitor troubleshooting.

https://www.youtube.com/results?search_query=trane+xr+fan+not+spinning

 

[popper]

Vinegar in drain pan will eat up the galvanized pan, but OK for PVC. Ammonia is hard on PVC. Insulated screwdriver across the terminals of the cap to discharge it. Don't short a cap you want to re-use!

 

[oldag]

A 50-50 mix of bleach and hot water will do the trick.

 

[Mowingmaniac 24/7]

I couldn't bear to read the previous posts...we just spent a week and a half without AC and it was just now fixed...to the tune of thousands, but who cares, we once again have cold/dehumidified air again...

 

[GeorgeS]

Alright. Last night was uncomfortable without A/C but thankfully, temps dropped into the low 70s. I started the A/C back up at 8am, and it was running fine all morning, naturally

I called an HVAC outfit here at 8am and the technician showed at noon. He checked things out - drain line was clear, coolant level is good, and the capacitor is fine.

The only thing he found was that the fan motor was drawing 103 amps (max rating is 95, normal is about 75). He suspects that it's overheating and shutting down. He could not state authoritatively that replacing the fan motor would (about $1000 with labor and warranty) solve the issue, so I'll keep an eye on it and use it a bit more sparingly for now.

Thank you to everyone who offered suggestions!

 

[GeorgeS]

BTW, I have an healthy respect and natural reluctance to mess with high-voltage.

 

[PinnedandRecessed]

The only thing he found was that the fan motor was drawing 103 amps (max rating is 95, normal is about 75). He suspects that it's overheating and shutting down. He could not state authoritatively that replacing the fan motor would (about $1000 with labor and warranty) solve the issue, so I'll keep an eye on it and use it a bit more sparingly for now.

We had a capacitor go out and shortly after that our fan was not wanting to start up and quit on us a few times. The last time it failed we (luckily) got it started and just let it run until it was able to be replaced. It basically came down to, "What is a good night's sleep worth?". Variable speed blowers are expensive and a PITA. We ultimately just replaced the inside unit (a Carrier that was 12yrs old). Moving to Texas has been a learning experience for us when it comes to home maintenance, be it the appliance longevity, insulation (or lack thereof for water pipes), heat pumps, roofs, insect control, and concrete foundations. I had never heard of "watering your foundation" until this year.

 

[FireInTheWire]

BTW, I have an healthy respect and natural reluctance to mess with high-voltage.

It’s just 240v. What’s the worst that could happen? Hold my beer…

 

[TexasRedneck]

Alright. Last night was uncomfortable without A/C but thankfully, temps dropped into the low 70s. I started the A/C back up at 8am, and it was running fine all morning, naturally

I called an HVAC outfit here at 8am and the technician showed at noon. He checked things out - drain line was clear, coolant level is good, and the capacitor is fine.

The only thing he found was that the fan motor was drawing 103 amps (max rating is 95, normal is about 75). He suspects that it's overheating and shutting down. He could not state authoritatively that replacing the fan motor would (about $1000 with labor and warranty) solve the issue, so I'll keep an eye on it and use it a bit more sparingly for now.

Thank you to everyone who offered suggestions!

$1k sounds WAY high - what company? Feel free to PM it if you wish - but those motors are nowhere near that high.

 

[oldag]

Alright. Last night was uncomfortable without A/C but thankfully, temps dropped into the low 70s. I started the A/C back up at 8am, and it was running fine all morning, naturally

I called an HVAC outfit here at 8am and the technician showed at noon. He checked things out - drain line was clear, coolant level is good, and the capacitor is fine.

The only thing he found was that the fan motor was drawing 103 amps (max rating is 95, normal is about 75). He suspects that it's overheating and shutting down. He could not state authoritatively that replacing the fan motor would (about $1000 with labor and warranty) solve the issue, so I'll keep an eye on it and use it a bit more sparingly for now.

Thank you to everyone who offered suggestions!

Been a few years since I replaced a fan motor, but it was less than $100.

Very easy job to do. Shut off power to A/C outside unit. Remove top grill, swap motor.

 

[TexasRedneck]

It’s just 240v. What’s the worst that could happen? Hold my beer…

240v?!?? Pshaw - you ain't lived until you have to disconnect an OLD irrigation pump (circa 1920/30)....wired for 11 or 12k volts! Rewind shop I called thought I was on drugs when I first talked to them....but confirmed the voltage when I got it there. They had to get one of the old hands in to do the repair on it. Turns out those old motors run about forever...IF they don't electrocute ya!

 

[SA_Steve]

There's a youtube guy who is an AC repair/distributor for Trane. Loves the Trane's but now replaces the contactor they come with before he even does a new install. Warranty repair costs him money and he believes this eliminates most of them.

https://www.youtube.com/channel/UCFxf3hjNRSQ706L3jgDYnBw

My house has two units and every 4 or 5 years I replace the contactors and capacitors just for the fun of it.
When I first moved in, summertime, both units quit on the same day ! AC guy got me good. $$$$$
Capacitor for one, contactor for the other.

 

[BBL]

The only thing he found was that the fan motor was drawing 103 amps (max rating is 95, normal is about 75). He suspects that it's overheating and shutting down. He could not state authoritatively that replacing the fan motor would (about $1000 with labor and warranty) solve the issue, so I'll keep an eye on it and use it a bit more sparingly for now.

I agree with others, a fan motor is a very easy swap and nowhere near a grand. Ouch.
Though didn't you say that your A/C is only 4 years old? No warranty on the original motor?
Outfits often quote incredible prices because they know that people will pay it to stay cool. But if you talk some sense to them, they can do it at normal prices. Cost of fan motor plus 1 hour of labor (tops). Unless your fan is made of gold, you should not be paying 4 digits. Something smells here.

 

[BBL]

BTW, I have an healthy respect and natural reluctance to mess with high-voltage.

Are we talking 110VAC? That is not considered HV. That's just house voltage. I've been stung by 240 in the past, I am used to it, 110 feels like a buzz now.
True high voltage starts in the kV range. High voltage is deadly. No exceptions. I don't mess with HV. I am certified only up to 500V and I am okay with that. I'll leave the HV transmission lines to someone else. Those guys get paid more to work on that.

 

[FireInTheWire]

Voltage doesn’t kill.

 

[tangoparson]

Someone is jiving you. I almost guarantee if you look the house breaker to the unit is 50 amps. If it is running more than that on more than a very short surge that breaker will trip.

1. Fan motors in a home unit do NOT draw 100 amps.

2. The compressor in a home unit doesn’t draw 100 amp either. I work on commercial refrigeration and even our 20-25 hp compressor only pulls about 75-80 running.

3. $1000 to change a compressor is really a good price (the big energy consumer in the outside unit, normally 25-30 amps max!).

4. $1000 to change the outdoor fan motor is a first class fucking. The tech must have a payment on his Mercedes coming up.

Wash the outside unit really good so air can flow through. Change the caps just on general principles they are crap. (And keep a spare like several of us do) they only cost $25 to $30 wholesale.

The symptoms that have been described sure sounds to me like the condensate overflow switch in the inside unit. Take covers off and look.


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