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Tim H.
Tim H., HVAC Professional
Category: HVAC
Satisfied Customers: 3966
Experience:  Experienced in all aspects of HVAC, both residential and commercial.
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Ok. 1.5 yr old Lennox 5 ton unit that has been regularly

Customer Question

Ok. 1.5 yr old Lennox 5 ton unit that has been regularly maintained went out; it sounds like the compressor starts for 10 seconds then shuts off; fan is blowing on "on" and "auto" and I changed batteries in thermostat.
JA: I'll do all I can to help. Is there anything else the HVAC Technician should be aware of?
Customer: It just started happening today.
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the HVAC Technician about your situation and then connect you two.
Submitted: 4 months ago.
Category: HVAC
Expert:  Tim H. replied 4 months ago.

Hi, I'm Tim and I'm an HVAC expert here to assist you with your questions. Please provide all information I request as it makes it more difficult to troubleshoot something when I'm not there onsite. Essentially, you become my eyes and ears. Thanks for the opportunity to help. At the end of our dialog, you will have a chance to rate my service, but please wait until we are finished and you're satisfied you have all the information you need. Please be patient as many times we work with several customers at once.

Is it whole outside unit that turns on for 10 sec, then off, or just compressor?

Customer: replied 4 months ago.
Only the compressor. The fan continues to run.
Expert:  Tim H. replied 4 months ago.

Sounds like a stuck compressor. Have you checked run cap for compressor for signs of bulging or being deformed?

Customer: replied 4 months ago.
I don't know what a run cap is.
Expert:  Tim H. replied 4 months ago.

run capacitor. Inside the unit in the area where all the electrical components are. Looks similar to this.

Expert:  Tim H. replied 4 months ago.

Typically on a bad one the top will be deformed or "bulging"

Customer: replied 4 months ago.
I didn't get inside the unit. We called service for tomorrow but I thought I'd give this answer site a try. It's dark now, and I'm not skilled with AC units so probably not a good idea to pull panels off to look around. I'll see if the techs tomorrow to see if is the run cap. Thanks for your quick response. I'll sign off now unless you think there is some quick trouble shoot I missed.
Expert:  Tim H. replied 4 months ago.

Either way, it sounds like a stuck compressor. Whether compressor itself is bad or just run capacitor. Both can cause the compressor to not start or attempt to start, but not actually run. Let me know if you have additional questions. Otherwise, good luck! Thanks for using Just Answer and please don't forget to rate my service as that's how experts get paid (thanks in advance for any bonus left). Otherwise experts work at their own time and expense. Feel free to post back with any more questions. Remember, you can rate question at any point and still ask more questions (related to the same thing) later on. Experts prefer if you rate question at the end of our first chat.

Expert:  Tim H. replied 4 months ago.

Did you have further questions?