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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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What does it mean when the red light (DEF) comes on the

Customer Question

What does it mean when the red light (DEF) comes on the machine
JA: I'll do all I can to help. How long have you been dealing with this?
Customer: just tiday, the system wont operate on auto
JA: Do you plan on doing the work yourself?
Customer: what work?
JA: Anything else we should know to help you best?
Customer: no
Submitted: 1 month ago.
Category: HVAC
Expert:  Phil replied 1 month ago.

Hello,I am a retired mechanical engineer with 56 years in this business. I will go in depth with you, and up to a 6 hour time limit.

All I ask is please select the ***RATING LINK*** at the top of your page before leaving, that is the only way I am credited through the site.

Rating does not affect your charges nor ability to refund if not satisfied. If you can agree to that, lets continue by all means.

.

DEF usually means 'defrost' and it applies to heat pump type AC systems, if you can give me the brand and model number of the unit that sits outside I can see what you have, we can go from there in 6 hours, I am off to bed its late here.

There are no other HVAC experts on line here tonight apparently. However if you want faster service there is a chance that someone else will log on and help you before I get up....in that case just opt me out so that your question goes back up on the board.

If you work with me you will need a multi meter and may need to send me a photo of the unit wiring diagram if the manual for your system is not on line.