I think my compressor died

[davidlee]

We had a storm today and I realized the A/C wasn't working properly. I check at the contactor and was getting 244 volts on both sides with the tstat calling for cool. Its a 4 ton Lennox about 9 years old. Question, Replace the compressor or the whole outside unit?

 

[Falcon67]

I would call a service tech - it may just be a problem with a capacitor or the contactor. It may not - having just done this - be economical in the long term to repair units that are as old as yours. In some cases, parts are not available or if they are, expensive. To replace our compressor was going to be nearly 1/4 a whole new system.

 

[bczygan]

Oh man, I was worried for a second that it was your AIR compressor!.........Whew!

 

[davidlee]

Oh man, I was worried for a second that it was your AIR compressor!.........Whew!

No, thank goodness that would be serious.

 

[bonneyman]

R-22 unit? Do all you can to keep it going. You do not want one of the new 410a systems until you have to.

Lennox built a solid unit. And most every part can still be replaced. Yeah, some of the fancy electronic control boards can get a little hard to find. But a good service tech can get you going old school.

 

[davidlee]

I am going to call someone out on Monday. I opened up the electrical service panel and the contactor is working and their does not appear to have a printed circuit board. The unit is an A/C only not a heat pump. The fan operates ok so that's why I think its the compressor. It probably did not help matters that my daughter kept the unit on 66 degrees for five days and I am sure the unit ran almost the whole time. We have been running about 96 outside for the past few weeks and 80 percent humidity.

 

[MattVette89]

I replaced the capacitor on my Lennox ac unit today. If you have a bad cap (or at least the compressor portion of a dual run cap), the compressor won't kick on. If you have a multimeter that can read microfarads, you can test the capacitor yourself and possibly save the service call. Turn off the power, disconnect the wires, discharge the cap using a screwdriver from common to fan and common to herm (compressor). Pull cap (makes it easier) and test the common to herm with the multimeter. The cap should say on the side what the normal reading is and what the tolerance is. If it is out of tolerance, replace the cap.

http://www.hvacpartsoutlet.com/troubleshootacapacitor.aspx

I am not an HVAC tech, so any pros feel free to comment on what I posted.

 

[zmaxmotorsports]

It could be a bad cap.

 

[firworks]

R-22 unit? Do all you can to keep it going. You do not want one of the new 410a systems until you have to.

Lennox built a solid unit. And most every part can still be replaced. Yeah, some of the fancy electronic control boards can get a little hard to find. But a good service tech can get you going old school.

Why don't you want a new 410a system? I'm hobbling along my original York AC that was installed when my house was built in the 60's. I keep considering calling someone out to get an estimate to have the system replaced but don't want to spend the cash until it dies for good.

 

[Falcon67]

Out 410 unit is running 1/2 the time the old R22 unit did, same size. Quieter and move more air too.

 

[monkeyspanners]

Capacitor would be the favorite, though if you leave it long enough trying to run with a failed capacitor it will damage the compressor.
The long run time should not do any harm, some commercial stuff runs non stop.

 

[LS6 Tommy]

R-22 unit? Do all you can to keep it going. You do not want one of the new 410a systems until you have to.

Where did THAT come from?

Tommy

 

[LS6 Tommy]

I replaced the capacitor on my Lennox ac unit today. If you have a bad cap (or at least the compressor portion of a dual run cap), the compressor won't kick on. If you have a multimeter that can read microfarads, you can test the capacitor yourself and possibly save the service call. Turn off the power, disconnect the wires, discharge the cap using a screwdriver from common to fan and common to herm (compressor). Pull cap (makes it easier) and test the common to herm with the multimeter. The cap should say on the side what the normal reading is and what the tolerance is. If it is out of tolerance, replace the cap.

http://www.hvacpartsoutlet.com/troubleshootacapacitor.aspx

I am not an HVAC tech, so any pros feel free to comment on what I posted.

Shorting a capacitor is a REALLY good way to kill it if it isn't already bad. It can also cause it to burst.

Tommy

 

[Mike007]

I don't believe the issues in the HVAC industry have anything to do with the refrigerant. That said, I would hold onto a good working older unit as long as I could. There are huge quality issues right now in the industry and it includes all brands. Maybe they will eventually be resolved, maybe not.

 

[bonneyman]

I have never been a fan of 410a. I wouldn't put it on my house - and I'm a contractor. So, I wouldn't sell it to a customer.

But since R22 has been mandated as harmful the powers that be have banned it in new production and only 410a units are available. So I tell my customers let's keep your 22 unit going as long as we can. Parts are still available, and I have 20+ year old units that I still maintain. In fact, I have one 42 year old unit that still works.

Lennox is one of the old companies. They've been around a long time. Worked on alot of them, very solidly built. A 1990 unit will still have life in it. The only possible problem could be if the evap coil is rusted out/starts to leak. But that doesn't sound like the problem you have. The service tech can easily examine the coil when he's there and determine if it's getting close to failure.

Definitely check the caps and associated wiring. I've had a bad wire bite my in the ****.

 

[bonneyman]

I don't believe the issues in the HVAC industry have anything to do with the refrigerant. That said, I would hold onto a good working older unit as long as I could. There are huge quality issues right now in the industry and it includes all brands. Maybe they will eventually be resolved, maybe not.

Definitely there are QA issues going. Many revolve around evap coil problems.

 

[Mike007]

Definitely there are QA issues going. Many revolve around evap coil problems.

1999 to 2007, I had 1 evaporator coil leak on a system I installed. 2007 until now I'm around 60. Yes, 60 and that number continues to grow. And covers 5 brands.

 

[davidlee]

Ok guys first, thanks for all the info. Here's the deal, I had turned the unit off yesterday when it quit. I decided just to check it out again today and I seems to be working fine. Is there some type of auto reset high limit switch or something that would have cut out the compressor after it got too hot? Does the capacitor have a function while the unit runs or is it just for the start mode?
I have a low end Fluke meter but I don't think it can test MFD. It is a single cap unit or at least that is all I saw in the electrical service area.















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[Rockhead261]

All compressors have internal thermal limit switches. Yours apparently tripped and reset. Many causes, undercharge, bad run cap, and poor electrical connections being just a few. Wouldn't be a bad idea to have a tech check it out.

 

[TheEquineFencer]

Oh man, I was worried for a second that it was your AIR compressor!.........Whew!

That's what I was thinking...

I'd check the Cap on the motor/comp. first. If you have a Fluke 87V it can check the cap.

 

[bonneyman]

All compressors have internal thermal limit switches. Yours apparently tripped and reset. Many causes, undercharge, bad run cap, and poor electrical connections being just a few. Wouldn't be a bad idea to have a tech check it out.

Good advice here.

 

[LS6 Tommy]

All compressors have internal thermal limit switches. Yours apparently tripped and reset. Many causes, undercharge, bad run cap, and poor electrical connections being just a few. Wouldn't be a bad idea to have a tech check it out.

^^^This.^^^

Tommy